CN106564390A

CN106564390A - Electric automobile and high-voltage system, detection method and pre-charging circuit thereof

Info

Publication number: CN106564390A
Application number: CN201510661101.8A
Authority: CN
Inventors: 邵桂欣
Original assignee: Beijing Electric Vehicle Co Ltd
Current assignee: Beijing Electric Vehicle Co Ltd
Priority date: 2015-10-12
Filing date: 2015-10-12
Publication date: 2017-04-19
Anticipated expiration: 2035-10-12
Also published as: WO2017063561A1; CN106564390B

Abstract

The invention discloses an electric automobile, a high-voltage system, a detection method and a pre-charging circuit thereof. Wherein, this electric automobile's high-pressure system includes: the power battery circuit comprises a power battery and a negative relay, wherein the first end of the negative relay is connected to the negative electrode of the power battery; a pre-charge circuit in series with the power cell circuit, the pre-charge circuit comprising: the pre-charging relay and the pre-charging resistor matrix are connected with the anode relay in parallel, the pre-charging relay is connected with the pre-charging resistor matrix in series, and the pre-charging resistor matrix comprises a plurality of pre-charging resistors; and the controller is respectively connected with the anode relay, the cathode relay and the pre-charging relay and is used for controlling the high-voltage system to be safely powered on by using the pre-charging resistor matrix after the cathode relay, the pre-charging relay and the anode relay are controlled to be sequentially switched on. The invention solves the technical problem that the impulse current exists instantly when the pre-charging relay is closed under the condition that a single pre-charging resistor is short-circuited.

Description

Electric automobile and high-voltage system, detection method and pre-charging circuit thereof

Technical Field

The invention relates to the field of new energy automobiles, in particular to an electric automobile, a high-voltage system, a detection method and a pre-charging circuit thereof.

Background

New energy vehicles (such as pure electric vehicles, hybrid electric vehicles and fuel cell vehicles) comprise two voltage systems of low voltage and high voltage. The low-voltage system is used as a control system of the new energy automobile, and the high-voltage system is used as an energy supply system and a driving system of the new energy automobile. The voltage grade of the high-voltage system is generally higher than 200V, and the high-voltage system has the characteristics of high voltage and large current and exceeds the safe voltage range of personnel. The energy supply system of the new energy automobile comprises a battery system, wherein the load of the battery system is a plurality of high-voltage load components such as a motor system, and the input ends of the high-voltage load components are connected with high-voltage large-capacity voltage-stabilizing capacitors in order to ensure the stability of the voltage at the input ends of the high-voltage load components; in order to reduce the current impact when the system is powered on, a pre-charging loop is arranged in the high-voltage loop.

Fig. 1 is a precharge circuit diagram of a new energy vehicle according to the prior art, as shown in fig. 1: the pre-charging loop consists of a pre-charging contactor, a pre-charging resistor and an anode contactor, wherein the pre-charging resistor is a single power resistor. This precharge return circuit simple structure to under the circuit does not have the trouble, can solve the problem of power-on process current impact, nevertheless because precharge contactor does not have state feedback, when the circuit inner part breaks down, the problem of the big current impact damage system component of the appearance that can't avoid. And the control system cannot diagnose and determine when the pre-charge resistor is short-circuited.

In view of the above-mentioned problem that the pre-charging contactor has no state feedback and cannot judge whether a fault occurs inside the circuit, the pre-charging circuit in fig. 1 is improved in the prior art, fig. 2 is a pre-charging circuit diagram of another new energy automobile according to the prior art, as shown in fig. 2, the pre-charging contactor in the pre-charging circuit adds a feedback state, accesses a control unit of the whole automobile, and adds a battery terminal voltage detection and a pre-charging post-voltage detection (as shown in V1 and V2). The precharge circuit shown in fig. 2 can detect the state of the precharge contactor and the precharge process, but it is still impossible to avoid the problem of instantaneous rush current when closing the precharge contactor in the case of a short circuit of the precharge resistor, and the control system cannot diagnose and determine in the case of a failure in the precharge circuit.

In view of the above-mentioned problem that there is an impulse current instantaneously when the precharge resistor is short-circuited and the precharge contactor is closed, no effective solution has been proposed at present.

Disclosure of Invention

The embodiment of the invention provides an electric automobile, a high-voltage system, a detection method and a pre-charging circuit thereof, and aims to at least solve the technical problem that an impulse current exists instantly when a pre-charging relay is closed under the condition that a single pre-charging resistor is short-circuited.

According to an aspect of an embodiment of the present invention, there is provided a high voltage system of an electric vehicle, including: the power battery circuit comprises a power battery and a negative relay, wherein the first end of the negative relay is connected to the negative electrode of the power battery; a pre-charge circuit in series with the power cell circuit, the pre-charge circuit comprising: the pre-charging relay and the pre-charging resistor matrix are connected with the anode relay in parallel, the pre-charging relay is connected with the pre-charging resistor matrix in series, and the pre-charging resistor matrix comprises a plurality of pre-charging resistors; and the controller is respectively connected with the anode relay, the cathode relay and the pre-charging relay and is used for controlling the high-voltage system to be safely powered on by using the pre-charging resistor matrix after the cathode relay, the pre-charging relay and the anode relay are controlled to be sequentially switched on.

Further, the pre-charge resistor matrix includes: the pre-charging resistor set comprises N groups of pre-charging resistor sets, each group of pre-charging resistor sets is connected in parallel, each group of pre-charging resistor sets comprises at least one pre-charging resistor, and under the condition that any one group of pre-charging resistor sets comprises a plurality of pre-charging resistors, each pre-charging resistor contained in each pre-charging resistor set is connected in series.

Further, the system further comprises: the first voltmeter is connected with the power battery in parallel and used for detecting a first voltage value of the power battery; a first end of the second voltmeter is connected to a node between the pre-charging relay and the pre-charging resistor matrix, and a second end of the second voltmeter is connected with a second end of the negative relay and is used for detecting a second voltage value of the pre-charging resistor; the third voltmeter is connected with the high-voltage load in parallel and used for detecting a third voltage value at two ends of the high-voltage load; the controller is also used for controlling the high-voltage system to be safely electrified according to the detected first voltage value, the second voltage value and the third voltage value in the process of controlling the negative relay, the pre-charging relay and the positive relay to be sequentially switched on.

Further, after the controller completes power-on initialization, reading a first voltage value, and if the read first voltage value is smaller than a preset voltage, determining that the control of the maintenance switch is failed to be closed, controlling the high-voltage system to interrupt power-on; and if the read first voltage value is larger than or equal to the preset voltage, reading the state identification information of the negative relay, if the read state identification information of the negative relay meets a preset first preset condition, determining that the control of the maintenance switch is successfully closed and the negative relay is in a connected state, controlling the high-voltage system to interrupt power supply, and otherwise, determining that the control of the maintenance switch is successfully closed and the negative relay is in a disconnected state.

Further, under the condition that the control of the overhaul switch is successfully closed and the negative relay is in the off state, the controller sends an instruction for controlling the negative relay to be closed, at the moment, the state identification information of the negative relay is read, if the read state identification information of the negative relay does not meet a first preset condition, the control of the negative relay to be closed is determined to be failed, the high-voltage system is controlled to be powered off, and otherwise, the control of the overhaul switch to be successfully closed and the control of the negative relay to be successfully closed are determined.

Further, under the condition that the cathode relay is determined to be successfully closed, the first voltage value and the second voltage value are read, if the difference value between the read first voltage value and the read second voltage value is within a preset range, the overhaul switch is determined to be in a closed state, the cathode relay is determined to be in a connected state, and the pre-charging relay is determined to be in a connected state, the high-voltage system is controlled to be powered off, otherwise, the overhaul switch is determined to be successfully closed, the cathode relay is determined to be successfully connected, and the pre-charging relay is determined to be in a disconnected state.

Further, under the condition that the control of the overhaul switch is successfully closed, the control of the negative relay is successfully closed and the pre-charging relay is in the off state, the first voltage value and the second voltage value are read at the moment, if the read first voltage value is not equal to the read second voltage value, the control of the pre-charging relay is determined to be failed to be closed, the high-voltage system is controlled to be powered off, and otherwise, if the difference value of the read first voltage value and the read second voltage value is within a preset range, the control of the overhaul switch is successfully closed, the control of the negative relay is successfully closed and the control of the pre-charging relay is successfully closed are determined.

Further, under the condition that the control of the overhaul switch is successfully closed, the control of the negative relay is successfully closed and the pre-charging relay is in the off state, the controller sends out an instruction for controlling the closing of the pre-charging relay, at the moment, the state identification information of the pre-charging relay is read, if the read state identification information of the pre-charging relay does not meet a second preset condition, the control of the closing of the pre-charging relay is determined to be failed, the high-voltage system is controlled to be powered off, otherwise, if the read state identification information of the pre-charging relay meets the second preset condition, the control of the closing of the overhaul switch is determined to be successful, the control of the connection of the negative relay.

Further, under the condition that the control of the overhaul switch is successfully closed, the control of the negative relay is successfully closed and the control of the pre-charging relay is successfully closed, the third voltage value detected in real time is read, the third voltage value is compared with a pre-stored safety voltage value, if the increase rate of the third voltage value after being compared with the safety voltage value in unit time is lower than a preset threshold value, it is determined that the resistor in the pre-charging resistor matrix is disconnected, and if the increase rate of the third voltage value in unit time is higher than the preset threshold value, it is determined that the resistor in the pre-charging resistor matrix is short-circuited.

Further, under the condition that the pre-charging resistor matrix is determined to have a resistor open circuit or a resistor short circuit, the resistor set which is not open circuit or short circuit meets the resistance power of the high-voltage system, and the controller sends out an instruction for controlling the positive relay to be closed, so that the positive relay is switched on.

According to another aspect of the embodiments of the present invention, there is also provided a method of detecting a high voltage system of an electric vehicle, the high voltage system including: the power battery circuit comprises a power battery and a negative relay, wherein the first end of the negative relay is connected to the negative electrode of the power battery; a pre-charge circuit in series with the power cell circuit, the pre-charge circuit comprising: the pre-charging relay and the pre-charging resistor matrix are connected with the anode relay in parallel, the pre-charging relay is connected with the pre-charging resistor matrix in series, and the pre-charging resistor matrix comprises a plurality of pre-charging resistors; a controller connected to the positive relay, the negative relay, and the pre-charge relay, respectively, wherein the method comprises: and after the controller controls the negative relay, the pre-charging relay and the positive relay to be sequentially switched on, the controller controls the high-voltage system to be safely powered on by using the pre-charging resistor matrix.

Further, the system further comprises: the first voltmeter is connected with the power battery in parallel and used for detecting a first voltage value of the power battery; a first end of the second voltmeter is connected to a node between the pre-charging relay and the pre-charging resistor matrix, and a second end of the second voltmeter is connected with a second end of the negative relay and is used for detecting a second voltage value of the pre-charging resistor; a third voltmeter connected in parallel with the high-voltage load for detecting a third voltage value at two ends of the high-voltage load, wherein the method further comprises: and the controller controls the high-voltage system to be safely powered on according to the detected first voltage value, second voltage value and third voltage value and the state identification information of the negative relay read by the controller in the process of controlling the negative relay, the pre-charging relay and the positive relay to be sequentially switched on.

According to still another aspect of the embodiments of the present invention, there is also provided a precharge circuit provided between a power battery circuit and a high-voltage load, the precharge circuit including: a first sub-precharge circuit comprising: a positive relay; a second sub-precharge circuit connected in parallel with the first sub-precharge circuit, comprising: a pre-charge relay and a pre-charge resistance matrix connected in series, the pre-charge resistance matrix comprising a plurality of pre-charge resistances.

According to another aspect of the embodiment of the present invention, there is also provided an electric vehicle, including: the high-pressure system of any one of the embodiments of the present application.

According to still another aspect of the embodiments of the present invention, there is also provided an electric vehicle, including: any one of the precharge circuits in the embodiments of the present application.

In the embodiment of the invention, a power battery circuit is adopted and comprises a power battery and a negative relay, wherein the first end of the negative relay is connected with the negative electrode of the power battery; a pre-charge circuit in series with the power cell circuit, the pre-charge circuit comprising: the pre-charging relay and the pre-charging resistor matrix are connected with the anode relay in parallel, the pre-charging relay is connected with the pre-charging resistor matrix in series, and the pre-charging resistor matrix comprises a plurality of pre-charging resistors; the controller is respectively connected with the positive relay, the negative relay and the pre-charging relay, and is used for controlling the negative relay, the pre-charging relay and the positive relay to be sequentially switched on, controlling the high-voltage system to be safely powered on by using the pre-charging resistance matrix, and achieving the purpose of reducing impact current when the pre-charging resistance is short-circuited by using the pre-charging resistance matrix in a pre-charging circuit, so that the technical problem that the impact current exists in the closed pre-charging relay instantly under the condition that the single pre-charging resistance is short-circuited is solved.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:

fig. 1 is a precharge circuit diagram of a new energy vehicle according to the prior art;

FIG. 2 is a circuit diagram of a pre-charging circuit of a new energy automobile according to the prior art;

FIG. 3 is a schematic diagram of an electric vehicle high voltage system according to an embodiment of the invention; and

fig. 4 is a circuit diagram of an alternative high voltage system for an electric vehicle according to an embodiment of the invention.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

Example one

According to an embodiment of the present invention, an embodiment of a high voltage system of an electric vehicle is provided, and fig. 3 is a schematic diagram of the high voltage system of the electric vehicle according to the embodiment of the present invention; fig. 4 is a circuit diagram of an alternative high voltage system for an electric vehicle according to an embodiment of the invention. In fig. 4, BMS: a battery management system of the power battery; VMS: a vehicle control unit; the capacitor C represents the equivalent capacitance of a plurality of high-voltage load input capacitors; k1: a maintenance switch; k2: a negative relay; k3: a pre-charge relay; k4: a positive relay; r1 to Rn: a pre-charge resistor; v1, V2 and V3 are voltage detection circuits; and A is a current sensor. Label a: the control end of the negative relay is connected with the BMS; marking B: the control end of the pre-charging relay is connected to the BMS; label C: the control end of the positive relay is connected with the BMS; marking D: the state feedback end of the negative relay is connected into the BMS; label E: the state feedback end of the pre-charging relay is connected into the BMS; the designation F: and the state feedback end of the positive relay is connected into the BMS.

As shown in fig. 3, the system includes:

the power battery circuit 10 comprises a power battery and a negative pole relay, wherein the first end of the negative pole relay is connected to the negative pole of the power battery.

Specifically, the power battery in the power battery circuit 10 may provide energy for a high-voltage load of the electric vehicle, and the power battery is connected in series with the negative relay, and a negative electrode of the power battery is connected to a first end of the negative relay.

A pre-charge circuit 12 in series with the power cell circuit, the pre-charge circuit 12 may include: the pre-charging relay is connected with the pre-charging resistance matrix in series, and the pre-charging resistance matrix comprises a plurality of pre-charging resistances.

And the controller 14 is respectively connected with the positive relay, the negative relay and the pre-charging relay and is used for controlling the high-voltage system to be safely electrified by using the pre-charging resistor matrix after controlling the negative relay, the pre-charging relay and the positive relay to be sequentially switched on.

In addition, with reference to fig. 3 and 4, the controller 14 may be a battery management system BMS of a power battery or a vehicle control unit VMS.

Optionally, the pre-charge resistor matrix may include: the pre-charging resistor set comprises N groups of pre-charging resistor sets, each group of pre-charging resistor sets is connected in parallel, each group of pre-charging resistor sets comprises at least one pre-charging resistor, and under the condition that any one group of pre-charging resistor sets comprises a plurality of pre-charging resistors, each pre-charging resistor contained in each pre-charging resistor set is connected in series.

It can be seen that the pre-charge resistor matrix may be a resistor matrix including a plurality of pre-charge resistors, for example, the pre-charge resistors may be N × N resistor matrix or N × M resistor matrix, where N, M is a natural number and N ≠ M. For example, as shown in fig. 4, in an alternative, the pre-charge resistor matrix may be a 3 × 3 resistor matrix, i.e., 3 resistors are connected in series to obtain a set of pre-charge resistor sets, and then the 3 sets of pre-charge resistor sets are connected in parallel. Here, the resistors in the pre-charge resistor matrix may be the same, or resistors with different resistance values may be selected as needed.

Analysis shows that, in the above embodiments of the present application, by using the pre-charge resistor matrix instead of the existing single pre-charge resistor, even when a short circuit occurs in a certain pre-charge resistor, other pre-charge resistors in the pre-charge resistor matrix can still achieve the purpose of protecting components in the system, and the problem of current surge caused by short circuit of the high-voltage loop due to short circuit of the pre-charge resistor can be avoided.

It should be noted that, as can be seen from the circuit diagrams shown in fig. 1 to 4, when the pre-charge resistor is one in the prior art, the equivalent high-voltage capacitance value input to the high-voltage load is C, and the terminal voltage of the power battery is [ V0, Vt ]]Precharge time of T<At 500ms, the precharge resistance R alone may be calculated as follows, based on T ≧ T ═ RC ln (1-V)_t/V₀) The resistance value R of the pre-charging resistor is less than or equal to-TC/l n (1-V)_t/V₀). The power P of a single pre-charge resistor can be calculated as follows, P ≧ V2V 2/R × 2T. When using the pre-charge resistor matrix, take 3 x 3 pre-charge resistor matrix as shown in fig. 4 as an example, when the pre-charge resistor values in the pre-charge resistor matrix are equalWhen the same individual precharge resistance value is used, i.e., R0 — R1 — … … -R9 — R, each precharge resistance power value is, in the case where all the precharge resistors in the precharge resistor matrix are normal: P1-P2- … … -P9-P/9; in the case of a short circuit of a certain resistor in the pre-charge resistor matrix, the value of each pre-charge resistor power is: P1-P2- … … -P9-P/4; in the case of a resistor open in the pre-charge point resistor matrix, the power value of each pre-charge resistor is: P1-P2-P … … -P9-P/9. Taking the maximum power value, the resistance power in the pre-charge resistance matrix may be: P1-P2-P … … -P9-P/4. That is, the resistance value of each of the pre-charge resistors in the pre-charge resistor matrix may be constant compared to the resistance value R of the single pre-charge resistor, and the power of each of the pre-charge resistors in the pre-charge resistor matrix may be one quarter of the power value of the single pre-charge resistor, i.e., P/4 compared to the power P of the single pre-charge resistor. The higher the power of the pre-charge resistor, the higher the limitation in the actual resistor selection, and the higher the cost of the resistor. By adopting the pre-charging resistor matrix, the limitation of selecting each pre-charging resistor in the pre-charging resistor matrix can be reduced, and the selected interval can be greatly widened when the resistors are actually selected. In addition, the volume of the resistor is in direct proportion to the power of the resistor, the volume of the resistor can be reduced by reducing the power, and when the power of each pre-charging resistor in the pre-charging resistor matrix is reduced, under the condition that the space of the electric automobile is limited, great convenience can be brought to physical and electrical specific design of the electric automobile, and the electric integration and thermal design of a system are facilitated. Furthermore, the price of the resistor is in direct proportion to the power of the resistor, and the cost of the pre-charging resistor can be greatly reduced due to the reduction of the power, so that the cost of the electric automobile can be controlled.

In addition, with reference to the embodiment shown in fig. 4, the controller 14 in the above embodiment of the present application may control the negative relay K2, the pre-charge relay K3, and the positive relay K4 to be sequentially turned on, so as to delay the current through the pre-charge resistor matrix, so that the current gradually increases along with the increase of the pre-charge time during the system power-on process, thereby avoiding the current impact on each component in the system during the system power-on process.

In an optional application scenario, as shown in fig. 4, when a certain pre-charge resistor in the pre-charge resistor matrix is short-circuited, the power of other pre-charge resistors on the branch where the pre-charge resistor short-circuit occurs is 1.5 times that of the branch where the pre-charge resistor short-circuit does not occur, and when the pre-charge time T is less than 500ms, the current in the circuit decreases as the pre-charge time increases, so that the other pre-charge resistors in the pre-charge resistor matrix where the short-circuit does not occur can still meet the pre-charge design requirements of the entire vehicle. The method still meets the requirement of resistance power for other pre-charging resistors which are not short-circuited in the pre-charging resistor matrix, only prolongs the pre-charging time, does not influence the high-voltage operation of the whole vehicle, and avoids the problem of current impact generated by a high-voltage loop caused by the short circuit of the pre-charging resistors.

In the embodiment of the present application, the negative relay may be a negative contactor, the positive relay may be a positive contactor, and the pre-charging relay may be a pre-charging contactor.

In conjunction with the embodiments shown in fig. 3 and 4, in the embodiment of the present invention, the power battery circuit 10 may include a power battery and a negative relay K2, wherein a first terminal of the negative relay K2 is connected to a negative terminal of the power battery; a pre-charge circuit in series with the power cell circuit, the pre-charge circuit 12 comprising: the pre-charging relay K3 and the pre-charging resistor matrix are connected with the positive electrode relay K4 in parallel, the pre-charging relay K3 is connected with the pre-charging resistor matrix in series, and the pre-charging resistor matrix comprises a plurality of pre-charging resistors; the controller 14 is respectively connected with the positive relay K4, the negative relay K2 and the pre-charging relay K3, and is used for controlling the safe electrifying mode of the high-voltage system by using the pre-charging resistance matrix after the negative relay K2, the pre-charging relay K3 and the positive relay K4 are sequentially switched on, and the pre-charging resistance matrix is used in the pre-charging circuit, so that the aim of reducing the impact current when the pre-charging resistance is short-circuited is achieved, and the technical problem that the impact current exists in the moment when the pre-charging relay is closed under the condition that a single pre-charging resistance is short-circuited is solved.

Optionally, as shown in fig. 4, the system may further include:

and the first voltmeter is connected with the power battery in parallel and is used for detecting the first voltage value of the power battery.

And a first end of the second voltmeter is connected to a node between the pre-charging relay K3 and the pre-charging resistor matrix, and a second end of the second voltmeter is connected with a second end of the cathode relay K2 and is used for detecting a second voltage value of the pre-charging resistor.

And the third voltmeter is connected with the high-voltage load in parallel and used for detecting a third voltage value at two ends of the high-voltage load.

The controller is also used for controlling the high-voltage system to be safely electrified according to the first voltage value, the second voltage value and the third voltage value obtained through detection in the process of controlling the negative electrode relay K2, the pre-charging relay K3 and the positive electrode relay K4 to be sequentially switched on.

Optionally, the controller is further configured to control a service switch inside the power battery to be turned on after the power-on initialization is completed, wherein if the service switch is not controlled to be turned on, the high-voltage system is controlled to interrupt power-on; the controller is also used for controlling the high-voltage system to be powered off under the condition that the maintenance switch is controlled to be successfully closed and the cathode relay is in a connected state.

According to the scheme, in an optional scheme, after the controller completes power-on initialization, the controller reads a first voltage value, and if the read first voltage value is smaller than a preset voltage, it is determined that the control of the maintenance switch K1 fails to be closed, the high-voltage system is controlled to be powered off; if the read first voltage value is larger than or equal to the preset voltage, reading state identification information of the cathode relay K2, if the read state identification information of the cathode relay K2 meets a preset first preset condition, determining that the control of the overhaul switch K1 is successfully closed and the cathode relay K2 is in a connected state, controlling the high-voltage system to be powered off, and otherwise, determining that the control of the overhaul switch K1 is successfully closed and the cathode relay K2 is in a disconnected state.

Specifically, when the maintenance switch K1 is closed, the first voltmeter detects the voltage value of the power battery, and if the first voltage value of the first voltmeter is smaller than the preset voltage, a circuit fault is indicated, and the output voltage is not equal to the voltage of the power battery. The preset voltage here may be a preset calibration value, which is determined according to the nominal voltage of the power battery.

Optionally, the controller is further configured to control the negative relay to close if it is determined that the control of the service switch is successfully closed and the negative relay is in the open state, wherein if the control of the negative relay fails to close, the high-voltage system is controlled to interrupt power supply.

According to the scheme, in an optional scheme, under the condition that the control maintenance switch K1 is successfully closed and the negative relay K2 is in an open state, the controller sends a command for controlling the negative relay K2 to be closed, at the moment, state identification information of the negative relay K2 is read, if the read state identification information of the negative relay K2 does not meet a first preset condition, it is determined that the control of the negative relay K2 is failed to be closed, the high-voltage system is controlled to be powered off, and otherwise, it is determined that the control maintenance switch K1 is successfully closed and the control of the negative relay K2 is successfully closed.

Specifically, as shown in fig. 4, the state of determining whether the negative relay K2 is in the on state may also be determined by the state information identification, the state feedback terminal D of the negative relay K2 is connected to the controller, and the controller may determine whether the negative relay K2 is in the on state or the off state by whether the signal sent by the state feedback terminal D is at the high level or the low level.

Optionally, the controller is further configured to control the high-voltage system to interrupt power-on if the negative relay is successfully controlled to be closed and the pre-charge relay is in the on state.

As can be seen from the above solution, in an alternative solution, in the case that it is determined that the control of the negative relay K2 is successful, the first voltage value and the second voltage value are read, if the difference between the read first voltage value and the second voltage value is within a predetermined range, it is determined that the service switch K1 is in the closed state, the negative relay K2 is in the on state, and the precharge relay K3 is in the on state, the high-voltage system is controlled to interrupt power-on, otherwise, it is determined that the control of the service switch K1 is successful, the control of the negative relay K2 is successful, and the precharge relay K3 is in the off state. Preferably, the first voltage value and the second voltage value in this embodiment may be equal.

Specifically, in the case where it is determined that the control of negative relay K2 was successfully performed, when the difference between the first voltage value and the second voltage value is within the preset range, it indicates that precharge relay K3 is also in the on state. Because the controller controls the negative relay K2, the pre-charging relay K3 and the positive relay K4 to be closed in sequence, when the controller does not control the pre-charging relay K3 to be switched on, the pre-charging relay K3 is in a switched-on state, which indicates that the circuit is abnormal at the moment, for example, the pre-charging relay K3 is stuck.

Optionally, the controller is further configured to control the pre-charging relay to close if the service switch is successfully controlled to close, the negative electrode relay is successfully controlled to close, and the pre-charging relay is in an open state, wherein if the pre-charging relay is not successfully controlled to close, the high-voltage system is controlled to interrupt power-on.

As can be seen from the above solution, in an alternative solution, in the case that it is determined that the control maintenance switch K1 is successfully closed, the control cathode relay K2 is successfully turned on, and the precharge relay K3 is in the off state, the first voltage value and the second voltage value are read at this time, if the read first voltage value is not equal to zero and the second voltage value is zero, it is determined that the control precharge relay K3 is successfully turned off, the high-voltage system is controlled to stop power-on, otherwise, if the difference value between the read first voltage value and the read second voltage value is within a predetermined range, it is determined that the control maintenance switch K1 is successfully turned on, the control cathode relay K2 is successfully turned on, and the control precharge relay K3 is successfully turned on.

Optionally, under the condition that it is determined that the control service switch K1 is successfully closed, the control cathode relay K2 is successfully closed, and the precharge relay K3 is in the off state, the controller issues an instruction to control the closing of the precharge relay K3, at this time, the state identification information of the precharge relay K3 is read, if the read state identification information of the precharge relay K3 does not satisfy the second preset condition, it is determined that the closing of the precharge relay K3 fails, the high-voltage system is controlled to interrupt the power-on, otherwise, if the read state identification information of the precharge relay K3 satisfies the second preset condition, it is determined that the closing of the control service switch K1 is successful, the closing of the cathode relay K2 is successful, and the closing of the precharge relay K3 is successful.

Specifically, whether the precharge relay K3 is in the on state may also be determined by the state information identification, as shown in fig. 4, the state feedback terminal E of the precharge relay K3 is connected to the controller, and the controller may determine whether the precharge relay K3 is in the on state or the off state by whether the signal sent by the state feedback terminal E is at a high level or a low level.

It should be noted that, in the present application, the controller sequentially controls the negative relay K2, the pre-charge relay K3 and the positive relay K4 to be sequentially closed, and determines the states of the negative relay K2, the pre-charge relay K3 and the positive relay K4, so that convenience is brought to the fault diagnosis of the whole vehicle, and the safe operation of the whole vehicle is ensured.

Alternatively, as can be seen from fig. 4, in the case that it is determined that the control service switch K1 is successfully closed, the control cathode relay K2 is successfully turned on, and the pre-charge relay K3 is successfully closed, the third voltage value detected in real time is read and compared with a pre-stored safety voltage value, if the increase rate of the third voltage value compared with the safety voltage value in a unit time is lower than a predetermined threshold value, it is determined that there is a resistance open circuit in the pre-charge resistance matrix, and if the increase rate of the third voltage value in the unit time is higher than the predetermined threshold value, it is determined that there is a resistance short circuit in the pre-charge resistance matrix.

Specifically, after the controller controls the negative relay K2, the pre-charge relay K3 and the positive relay K4 to be closed in sequence, the state of the pre-charge resistor array may be determined by comparing the third voltage value detected by the current third voltmeter with the increase of the third voltage value of the pre-charge resistor array under normal conditions. And when the third voltage value increase rate is higher than the third voltage value increase rate of the pre-charge resistor array under the normal condition, determining that the resistor in the pre-charge resistor array is in a short circuit state.

Specifically, whether the positive relay K4 is in the on state may also be determined by the status information flag, as shown in fig. 4, the status feedback terminal F of the positive relay K4 is connected to the controller, and the controller may determine whether the positive relay K4 is in the on state or the off state by whether the signal sent by the status feedback terminal D is at a high level or a low level.

It should be noted that, in the pre-charging process, the state of each pre-charging resistor in the pre-charging resistor matrix can be determined according to the change rate of the third voltage value, which brings convenience to fault diagnosis of the whole vehicle and ensures safe operation of the whole vehicle.

Optionally, in the case that it is determined that there is a resistor open or short circuit in the pre-charge resistor matrix, if the resistor set which is not open or short circuit satisfies the resistor power of the high-voltage system, the positive relay is controlled to be closed.

As can be seen from the above solution, in an alternative solution, in the case that it is determined that there is a resistor open circuit or short circuit in the pre-charge resistor matrix, and the resistor set that is not open circuit or short circuit satisfies the resistor power of the high-voltage system, the controller issues a command to control the positive relay K4 to close, so that the positive relay K4 is turned on.

Specifically, under the condition that a resistor in the pre-charging resistor matrix is broken or short-circuited, the pre-charging resistor matrix does not influence the operation of a high-voltage system on the whole vehicle, the problem that the whole vehicle cannot be powered on due to current impact during short circuit or broken circuit does not exist, and the running function of the whole vehicle is guaranteed.

Example two

In accordance with an embodiment of the present invention, there is provided an embodiment of a method of detecting a high voltage system of an electric vehicle, it is noted that the steps illustrated in the flowchart of the drawings may be performed in a computer system such as a set of computer executable instructions and that, although a logical order is illustrated in the flowchart, in some cases, the steps illustrated or described may be performed in an order different than presented herein.

As can be seen from fig. 3 and 4, the high voltage system of the electric vehicle in the embodiment of the method of the present application may include: the power battery circuit can comprise a power battery and a negative relay K2, wherein the first end of the negative relay K2 is connected to the negative electrode of the power battery; a pre-charge circuit in series with the power cell circuit, the pre-charge circuit comprising: the pre-charging relay K3 and the pre-charging resistor matrix are connected with the positive electrode relay K4 in parallel, the pre-charging relay K3 is connected with the pre-charging resistor matrix in series, and the pre-charging resistor matrix comprises a plurality of pre-charging resistors; based on the above high-voltage system, the method for detecting the high-voltage system of the electric vehicle may include the following steps, based on the controllers of the positive relay K4, the negative relay K2, and the precharge relay K3:

in step S102, after controlling the negative relay K2, the pre-charge relay K3 and the positive relay K4 to be sequentially turned on, the controller controls the high voltage system to be safely powered on by using a pre-charge resistance matrix, wherein the pre-charge resistance matrix comprises a plurality of pre-charge resistances.

Specifically, the controller may be a battery management system, a vehicle controller, or other devices that may be used to control the relay.

It should be further noted that the controller controls the negative electrode relay K2, the pre-charge relay K3 and the positive electrode relay K4 to be sequentially switched on, and delays the current through the pre-charge resistor matrix, so that the current gradually increases along with the increase of the pre-charge time in the system power-on process, and the current impact on each component in the system during the system power-on process is avoided.

The embodiment of the present application includes, through the above-mentioned high-voltage system: the power battery circuit comprises a power battery and a negative electrode relay K2, wherein the first end of the negative electrode relay K2 is connected with the negative electrode of the power battery; a pre-charge circuit in series with the power cell circuit, the pre-charge circuit comprising: the pre-charging relay K3 and the pre-charging resistor matrix are connected with the positive electrode relay K4 in parallel, the pre-charging relay K3 is connected with the pre-charging resistor matrix in series, and the pre-charging resistor matrix comprises a plurality of pre-charging resistors; and the controller is respectively connected with the positive relay K4, the negative relay K2 and the pre-charging relay K3, and controls the high-voltage system to be safely powered on by using the pre-charging resistor matrix after controlling the negative relay K2, the pre-charging relay K3 and the positive relay K4 to be sequentially switched on. The technical problem that impulse current exists instantly when a pre-charging relay is closed under the condition that a single pre-charging resistor is short-circuited is solved.

Optionally, the system further comprises: the first voltmeter is connected with the power battery in parallel and used for detecting a first voltage value of the power battery; a first end of the second voltmeter is connected to a node between the pre-charging relay K3 and the pre-charging resistor matrix, and a second end of the second voltmeter is connected with a second end of the negative relay K2 and is used for detecting a second voltage value of the pre-charging resistor; and the third voltmeter is connected with the high-voltage load in parallel and used for detecting a third voltage value at two ends of the high-voltage load. In the solution provided in the above embodiment, an example including the following implementation steps may also be included:

in step S1021, the controller reads the detected first voltage value of the power battery, the detected second voltage value of the pre-charge resistor, and the detected third voltage value across the high-voltage load while controlling the negative electrode relay K2, the pre-charge relay K3, and the positive electrode relay K4 to be turned on in sequence.

In step S1022, the controller controls the high-voltage system to be safely powered on according to the detected first voltage value, second voltage value, and third voltage value and the state identification information of the negative relay K2 read by the controller.

Optionally, in step S1022, the step of controlling, by the controller, the high-voltage system to be safely powered up according to the detected first voltage value, second voltage value, and third voltage value and the state identification information of the negative relay K2 read by the controller includes the following steps:

and step S10221, after the power-on initialization is finished, the controller controls a maintenance switch inside the power battery to be closed.

In step S10222, if the read first voltage value is smaller than the preset voltage, the controller determines that the control of the maintenance switch fails to close, and controls the high voltage system to interrupt power supply.

Step S10223, if the read first voltage value is greater than or equal to the preset voltage, the controller reads the state identification information of the negative relay, if the read state identification information of the negative relay meets a preset first preset condition, the controller determines that the maintenance switch is successfully controlled to be closed and the negative relay is in a connected state, and controls the high-voltage system to interrupt electrification, otherwise, the controller determines that the maintenance switch is successfully controlled to be closed and the negative relay is in a disconnected state.

According to the scheme provided by the steps, in an optional scheme, after the controller controls the positive relay, the negative relay and the pre-charging relay to be switched off and the maintenance switch to be switched on, reading a first voltage value, and if the read first voltage value is smaller than a preset voltage, determining that the maintenance switch is not switched on, controlling the high-voltage system to be switched off; if the read first voltage value is larger than or equal to the preset voltage, reading state identification information of the cathode relay K2, if the read state identification information of the cathode relay K2 meets a preset first preset condition, determining that the control of the overhaul switch K1 is successfully closed and the cathode relay K2 is in a connected state, controlling the high-voltage system to be powered off, and otherwise, determining that the control of the overhaul switch K1 is successfully closed and the cathode relay K2 is in a disconnected state.

Optionally, in step S10223, after determining that the control service switch is successfully closed and the negative relay is in the open state, the method further includes:

in step S1023, the controller controls the negative relay to close.

Step S1024, the controller reads the state identification information of the cathode relay.

And step S1025, if the read state identification information of the negative relay does not meet the first preset condition, the controller determines that the negative relay is failed to be closed and controls the high-voltage system to interrupt power supply, otherwise, the controller determines that the maintenance switch is successfully closed and controls the negative relay to be successfully closed.

According to the scheme provided by the steps, in an optional scheme, under the condition that the control maintenance switch K1 is successfully closed and the negative relay K2 is in an open state, the controller sends out a command for controlling the negative relay K2 to be closed, at the moment, state identification information of the negative relay K2 is read, if the read state identification information of the negative relay K2 does not meet a first preset condition, the control negative relay K2 is determined to be failed to be closed, the high-voltage system is controlled to be powered off, and otherwise, the control maintenance switch K1 is determined to be successfully closed and the negative relay K2 is determined to be successfully closed.

Optionally, in step S1025, after determining that the controlling of the negative relay closing is successful, the method further includes:

in step S1026, the controller reads the first voltage value and the second voltage value.

Step S1027, if the difference value between the first voltage value and the second voltage value is in a preset range, the controller determines that the maintenance switch is successfully controlled to be closed, the negative relay is successfully controlled to be closed and the pre-charging relay is detected to be in a connection state, the controller controls the high-voltage system to stop electrifying, and otherwise, the controller determines that the maintenance switch is successfully controlled to be closed, the negative relay is successfully controlled to be closed and the pre-charging relay is detected to be in a disconnection state.

As can be seen from the solutions provided in the above steps, in an alternative solution, in the case where it is determined that the control of the negative relay K2 is successfully closed, the first voltage value and the second voltage value are read, and if the difference between the read first voltage value and the second voltage value is within a predetermined range, it is determined that the service switch K1 is in the closed state, the negative relay K2 is in the on state, and the precharge relay K3 is in the on state, the high-voltage system is controlled to interrupt power-on, otherwise, it is determined that the control of the service switch K1 is successfully closed, the control of the negative relay K2 is successfully closed, and the precharge relay K3 is in the off state.

Optionally, in step S1027, after determining that the control of the service switch is successfully closed and the control of the negative relay is successfully closed and detecting that the precharge relay is in the open state, the method further includes:

in step S1028, the controller controls the precharge relay to close.

In step S1029, the controller reads the first voltage value and the second voltage value.

Step S10210, if the read first voltage value is not equal to zero and the second voltage value is zero, determining that the closing of the pre-charging relay is controlled to fail, and the controller controls the high-voltage system to stop electrifying, otherwise, if the difference value of the read first voltage value and the read second voltage value is within a preset range, determining that the closing of the overhaul switch is controlled to succeed, the closing of the cathode relay is controlled to succeed, and the closing of the pre-charging relay is controlled to succeed.

As can be seen from the solutions provided in the above steps, in an alternative solution, in the case that it is determined that the control maintenance switch K1 is successfully closed, the control cathode relay K2 is successfully closed, and the precharge relay K3 is in the off state, the first voltage value and the second voltage value are read at this time, if the read first voltage value is not equal to zero and the second voltage value is zero, it is determined that the control precharge relay K3 is successfully opened, the high-voltage system is controlled to stop power-on, otherwise, if the difference between the read first voltage value and the second voltage value is within a predetermined range, it is determined that the control maintenance switch K1 is successfully closed, the control cathode relay K2 is successfully closed, and the control precharge relay K3 is successfully closed.

Optionally, in step S10210, after determining that the control of the service switch is successfully closed and the control of the negative relay is successfully closed and detecting that the precharge relay is in the open state, the method further includes:

in step S10211, the controller controls the precharge relay to close.

Step S10212, the controller reads the state identification information of the pre-charging relay; and if the read state identification information of the pre-charging relay does not meet the second preset condition, determining that the pre-charging relay is failed to be closed, and controlling the high-voltage system to be powered off by the controller.

Step S10213, if the read state identification information of the pre-charging relay meets a second preset condition, determining that the closing of the maintenance switch is controlled successfully, the connection of the cathode relay is controlled successfully, and the closing of the pre-charging relay is controlled successfully.

According to the scheme provided by the steps, in an optional scheme, under the condition that the control maintenance switch K1 is determined to be successfully closed, the control cathode relay K2 is successfully closed and the pre-charging relay K3 is in an off state, the controller sends out a command for controlling the pre-charging relay K3 to be closed, at the moment, the state identification information of the pre-charging relay K3 is read, if the read state identification information of the pre-charging relay K3 does not meet a second preset condition, the control pre-charging relay K3 is determined to be failed to be closed, the high-voltage system is controlled to be powered off, otherwise, if the read state identification information of the pre-charging relay K3 meets the second preset condition, the control maintenance switch K1 is determined to be successfully closed, the control cathode relay K2 is successfully turned on, and the control pre-charging relay K3.

Optionally, in step S10213, after determining that the control of the service switch is successfully closed, the control of the negative relay is successfully closed, and the control of the precharge relay is successfully closed, the method further includes:

in step S10214, the controller reads the third voltage value detected in real time.

In step S10215, the controller compares the third voltage value with a pre-stored safe voltage value.

In step S10216, the controller determines that there is a resistance open circuit in the pre-charge resistance matrix if the increase rate of the third voltage value compared with the safety voltage value in the unit time is lower than a predetermined threshold, and determines that there is a resistance short circuit in the pre-charge resistance matrix if the increase rate of the third voltage value in the unit time is higher than the predetermined threshold.

As can be seen from the above-mentioned steps, in an alternative scheme, in the case that it is determined that the control maintenance switch K1 is successfully closed, the control cathode relay K2 is successfully turned on, and the pre-charge relay K3 is successfully closed, the third voltage value detected in real time is read and compared with a pre-stored safety voltage value, if the increase rate of the third voltage value compared with the safety voltage value in a unit time is lower than a predetermined threshold value, it is determined that there is a resistance open circuit in the pre-charge resistance matrix, and if the increase rate of the third voltage value in the unit time is higher than the predetermined threshold value, it is determined that there is a resistance short circuit in the pre-charge resistance matrix.

Optionally, the method further comprises:

step S10217, in the case that the pre-charging resistor matrix is determined to have a resistor open circuit or a short circuit, if the controller detects that the resistor set which is not open circuit or short circuit meets the resistor power of the high-voltage system, the controller controls the positive relay to be closed, so that the positive relay is switched on.

As can be seen from the above solution, in an alternative solution, in the case that it is determined that there is a resistor open circuit or short circuit in the pre-charge resistor matrix, and the resistor set that is not open circuit or short circuit satisfies the resistor power of the high-voltage system, the controller issues a command to close the positive relay K4, so that the positive relay K4 is turned on.

EXAMPLE III

According to an embodiment of the present invention, there is provided a precharge circuit that may be provided between a power battery circuit and a high-voltage load of a high-voltage system as shown in fig. 4, the precharge circuit may include:

a first sub-precharge circuit comprising: and a positive electrode relay K4.

A second sub-precharge circuit connected in parallel with the first sub-precharge circuit, comprising: a pre-charge relay K3 and a pre-charge resistor matrix connected in series, the pre-charge resistor matrix comprising a plurality of pre-charge resistors.

In the embodiment of the application, the pre-charging resistor matrix formed by a plurality of pre-charging resistors is arranged in the pre-charging circuit, so that the technical problem that the impulse current exists instantly when the pre-charging relay is closed under the condition that a single pre-charging resistor is short-circuited is solved.

Example four

According to an embodiment of the invention, an electric vehicle is provided, which includes the high-voltage system of the electric vehicle in any one of the above embodiments.

It should be noted that the electric vehicle provided by the present application includes various preferred and alternative embodiments of the high voltage system of the electric vehicle provided in the first embodiment, but is not limited to the embodiment provided in the first embodiment.

EXAMPLE five

According to an embodiment of the present invention, there is provided an electric vehicle including any one of the precharge circuits in the third embodiment.

It should be noted here that the electric vehicle provided by the present application includes various preferred and alternative embodiments of the precharge circuit provided in the third embodiment, but is not limited to the embodiments provided in the third embodiment.

The above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.

In the above embodiments of the present invention, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.

In the embodiments provided in the present application, it should be understood that the disclosed technology can be implemented in other ways. The above-described embodiments of the apparatus are merely illustrative, and for example, the division of the units may be a logical division, and in actual implementation, there may be another division, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, units or modules, and may be in an electrical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a Read-only Memory (ROM), a Random Access Memory (RAM), a removable hard disk, a magnetic or optical disk, and other various media capable of storing program codes.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. A high voltage system for an electric vehicle, comprising:

the power battery circuit comprises a power battery and a negative relay, wherein the first end of the negative relay is connected to the negative electrode of the power battery;

a pre-charge circuit in series with the power cell circuit, the pre-charge circuit comprising: the pre-charging relay is connected with the pre-charging resistance matrix in series, and the pre-charging resistance matrix comprises a plurality of pre-charging resistances;

and the controller is respectively connected with the positive relay, the negative relay and the pre-charging relay and is used for controlling the high-voltage system to be safely powered on by using the pre-charging resistor matrix after the negative relay, the pre-charging relay and the positive relay are controlled to be sequentially switched on.

2. The system of claim 1, wherein the pre-charge resistor matrix comprises: the device comprises N groups of pre-charging resistor sets, wherein each group of pre-charging resistor sets are connected in parallel and comprise at least one pre-charging resistor, and under the condition that any one group of pre-charging resistor sets comprises a plurality of pre-charging resistors, each pre-charging resistor contained in each pre-charging resistor set is connected in series.

3. The system according to claim 1 or 2, characterized in that the system further comprises:

the first voltmeter is connected with the power battery in parallel and used for detecting a first voltage value of the power battery;

a first end of the second voltmeter is connected to a node between the pre-charging relay and the pre-charging resistor matrix, and a second end of the second voltmeter is connected with a second end of the negative relay and is used for detecting a second voltage value of the pre-charging resistor;

the third voltmeter is connected with the high-voltage load in parallel and used for detecting a third voltage value at two ends of the high-voltage load;

the controller is further used for controlling the high-voltage system to be safely powered on according to the first voltage value, the second voltage value and the third voltage value obtained through detection in the process of controlling the negative relay, the pre-charging relay and the positive relay to be sequentially switched on.

4. The system of claim 3,

the controller is also used for controlling the closing of a maintenance switch in the power battery after the power-on initialization is completed, wherein if the control of the closing of the maintenance switch fails, the high-voltage system is controlled to stop the power-on;

the controller is also used for controlling the high-voltage system to be powered off under the condition that the maintenance switch is successfully controlled to be closed and the cathode relay is in a connection state.

5. The system of claim 4,

the controller is further used for controlling the negative pole relay to be closed under the condition that the maintenance switch is successfully controlled to be closed and the negative pole relay is in the open state is determined, wherein if the condition that the negative pole relay is controlled to be closed fails, the high-voltage system is controlled to be powered off.

6. The system of claim 5,

the controller is also used for controlling the high-voltage system to be powered off if the negative electrode relay is controlled to be successfully closed and the pre-charging relay is in a switch-on state.

7. The system of claim 6,

the controller is also used for controlling the pre-charging relay to be closed under the conditions that the overhaul switch is controlled to be successfully closed, the cathode relay is controlled to be successfully closed and the pre-charging relay is in an off state, wherein if the pre-charging relay is controlled to be failed to be closed, the high-voltage system is controlled to be powered off.

8. A method of testing a high voltage system of an electric vehicle, comprising:

after a controller controls a negative relay, a pre-charging relay and a positive relay in the high-voltage system to be sequentially switched on, the high-voltage system is controlled to be safely powered on by using the pre-charging resistance matrix, wherein the pre-charging resistance matrix comprises a plurality of pre-charging resistances.

9. The method of claim 8,

the controller reads a detected first voltage value of the power battery, a detected second voltage value of the pre-charging resistor and a detected third voltage value at two ends of the high-voltage load in the process of controlling the negative relay, the pre-charging relay and the positive relay to be sequentially switched on;

and the controller controls the high-voltage system to be safely powered on according to the detected first voltage value, the detected second voltage value, the detected third voltage value and the read state identification information of the negative relay.

10. The method according to claim 9, wherein the step of controlling the high voltage system to be safely powered up by the controller according to the detected first voltage value, the detected second voltage value, the detected third voltage value and the read status identification information of the negative relay comprises:

after the power-on initialization is completed, the controller controls a maintenance switch inside the power battery to be closed;

if the read first voltage value is smaller than a preset voltage, the controller determines that the maintenance switch is failed to be closed, and controls the high-voltage system to be powered off;

if the read first voltage value is larger than or equal to the preset voltage, the controller reads the state identification information of the negative relay, if the read state identification information of the negative relay meets a preset first preset condition, the controller determines that the maintenance switch is controlled to be successfully closed and the negative relay is in a connected state, and controls the high-voltage system to be powered off, otherwise, the controller determines that the maintenance switch is controlled to be successfully closed and the negative relay is in a disconnected state.

11. The method of claim 10, wherein after determining that controlling the service switch to close was successful and the negative relay is in the open state, the method further comprises:

the controller controls the negative relay to be closed;

the controller reads the state identification information of the cathode relay; wherein,

and if the read state identification information of the negative relay does not meet the first preset condition, the controller determines that the negative relay is failed to be closed and controls the high-voltage system to be powered off, otherwise, the controller determines that the maintenance switch is successfully closed and controls the negative relay to be successfully closed.

12. The method of claim 11, wherein after determining that controlling the negative relay to close was successful, the method further comprises:

the controller reads the first voltage value and the second voltage value; wherein,

if the read difference value between the first voltage value and the second voltage value is within a preset range, the controller determines that the maintenance switch is successfully controlled to be closed, the negative relay is successfully controlled to be closed and the pre-charging relay is detected to be in a switch-on state, and controls the high-voltage system to be powered off, otherwise, the controller determines that the maintenance switch is successfully controlled to be closed, the negative relay is successfully controlled to be closed and the pre-charging relay is detected to be in a switch-off state.

13. The method of claim 12, wherein after determining that controlling the service switch to close is successful, controlling the negative relay to close is successful, and detecting that the pre-charge relay is in an open state, the method further comprises:

the controller controls the pre-charging relay to be closed;

if the read first voltage value is not equal to zero and the second voltage value is zero, determining that the pre-charging relay is controlled to be closed unsuccessfully, and controlling the high-voltage system to be powered off by the controller, otherwise, if the difference value between the read first voltage value and the read second voltage value is within the preset range, determining that the overhaul switch is controlled to be closed successfully, controlling the negative relay to be closed successfully, and controlling the pre-charging relay to be closed successfully.

14. The method of claim 12, wherein after determining that controlling the service switch to close is successful, controlling the negative relay to close is successful, and detecting that the pre-charge relay is in an open state, the method further comprises:

the controller controls the pre-charging relay to be closed;

the controller reads the state identification information of the pre-charging relay; wherein,

if the read state identification information of the pre-charging relay does not meet a second preset condition, determining that the pre-charging relay is controlled to be closed unsuccessfully, and controlling the high-voltage system to be powered off by the controller;

and if the read state identification information of the pre-charging relay meets the second preset condition, determining that the maintenance switch is successfully controlled to be closed, the negative relay is successfully controlled to be switched on, and the pre-charging relay is successfully controlled to be closed.

15. The method of claim 13 or 14, wherein after determining that controlling the service switch to close is successful, controlling the negative relay to turn on is successful, and controlling the pre-charge relay to close is successful, the method further comprises:

the controller reads the third voltage value detected in real time;

the controller compares the third voltage value with a pre-stored safe voltage value; wherein,

the controller determines that there is a resistance open circuit in the pre-charge resistance matrix if the rate of increase of the third voltage value compared with the safety voltage value per unit time is lower than a predetermined threshold, and determines that there is a resistance short circuit in the pre-charge resistance matrix if the rate of increase of the third voltage value per unit time is higher than the predetermined threshold.

16. The method of claim 15, wherein in the event that a resistive open or short circuit is determined within the pre-charge resistive matrix, the controller controls the positive relay to close if the set of non-open or short-circuited resistances is detected to meet the resistive power of the high voltage system, such that the positive relay is turned on.

17. A pre-charge circuit disposed between a power cell circuit and a high voltage load, the pre-charge circuit comprising:

a first sub-precharge circuit comprising: a positive relay;

a second sub-precharge circuit connected in parallel with the first sub-precharge circuit, comprising: a pre-charge relay and a pre-charge resistance matrix connected in series, the pre-charge resistance matrix comprising a plurality of pre-charge resistances.

18. The precharge circuit of claim 17, wherein the precharge resistor matrix comprises: the device comprises N groups of pre-charging resistor sets, wherein each group of pre-charging resistor sets are connected in parallel and comprise at least one pre-charging resistor, and under the condition that any one group of pre-charging resistor sets comprises a plurality of pre-charging resistors, each pre-charging resistor contained in each pre-charging resistor set is connected in series.

19. An electric vehicle, comprising: the high pressure system of any one of claims 1 to 7.

20. An electric vehicle, comprising: a precharge circuit as claimed in claim 17 or 18.