CN221596353U - Improved H-bridge control circuit suitable for control of breaker operating mechanism - Google Patents

Abstract

The utility model relates to an improved H-bridge control circuit suitable for control of a breaker operating mechanism, which comprises an opening and closing H-bridge control circuit of the breaker operating mechanism, wherein the load of the H-bridge control circuit is an exciting coil of the breaker operating mechanism, the improved H-bridge control circuit also comprises an auxiliary opening and closing control circuit, the auxiliary opening and closing control circuit is provided with a switching element, the input end of the switching element is connected with an energy storage element, and the auxiliary opening and closing control circuit is connected with the upper arm of an opening and closing control branch of the H-bridge control circuit in parallel. According to the utility model, under the condition that the main switching-off capacitor C2 of the H bridge control circuit is insufficiently charged, switching-off operation can be performed through the auxiliary switching-off control circuit, so that the switching-on holding force of the monostable breaker operating mechanism can be increased by 10% to 15% under a proper control strategy, and the switching-on reliability is effectively improved/ensured.

Description

Improved H-bridge control circuit suitable for control of breaker operating mechanism

Technical Field

The utility model relates to an improved H-bridge control circuit suitable for controlling/operating a monostable breaker operating mechanism.

Background

The operating mechanism of the power distribution network circuit breaker has undergone several generations of evolution, namely an electromagnetic operating mechanism, a spring operating mechanism, a permanent magnet operating mechanism and a magnetic control operating mechanism which is gradually popularized at present. The magnetic control mechanism of the circuit breaker has the advantages of high operation speed, low power consumption, simple structure, adoption of non-rare earth materials and the like, and is gradually popularized in a power system as the operation mechanism of the circuit breaker. The conventional common magnetic control mechanism mainly comprises a static iron core, a movable iron core and an exciting coil, an H-bridge circuit is adopted as a control circuit (which can be called an H-bridge control circuit), the exciting coil is used as a load in the H-bridge circuit, the on-off of related switch elements in the H-bridge circuit is controlled by a control device/controller (e.g. MCU), the switching of an opening-closing discharging loop is realized, the working state of the exciting coil is further controlled, the switching/holding of the switching/opening of a circuit breaker is realized, and the specific control mode is determined according to the control requirement of the magnetic control mechanism. Fig. 1 shows an H-bridge control circuit for a monostable breaker operating mechanism, the basic operating principle being as follows: when the breaker needs to be switched on, a switching-on command/instruction is sent out by the controller MCU, the CLOSE1 and the CLOSE2 become high level, the switching elements Q1 and Q4 are opened, the discharging current of the switching capacitor C1 sequentially passes through the switching element Q1, the exciting coil L and the switching element Q4 to form a discharging loop, the exciting coil L arranged in the magnetic control operating mechanism generates electromagnetic force to drive the movable iron core of the magnetic control mechanism to move to the attraction surface of the static iron core, the magnetic control mechanism forms a closed magnetic loop, and after the switching-on is completed and the switching-on of the switching elements Q1 and Q4 is completed, The coil L is powered off, the magnetic control mechanism can be reliably kept at a closing position by virtue of residual magnetism, external energy is not needed to maintain, and the closing pulse current time can be set to be 30 to 80 milliseconds; When the breaker needs to be opened, a switching-off command is sent out by the MCU, TRIP1 and TRIP2 are set to be high level, the switching elements Q2 and Q3 are opened, the discharging current in the switching-off capacitor C2 sequentially passes through Q2, L and Q3 to form a discharging loop, for the exciting coil L, the switching-off current is reverse current (opposite to the closing current), the electromagnetic force generated by the current counteracts the holding force (demagnetizing) of the magnetic control mechanism, and the magnetic control mechanism can realize switching-off by virtue of the built-in switching-off spring of the magnetic control mechanism and is reliably held at the switching-off position. Because the Q1 and Q4 are turned off simultaneously after the closing is completed, the closing current in the exciting coil L is suddenly turned off, and according to lenz's law, a reverse electromotive force is generated relative to the voltage direction of the closing capacitor, and the freewheeling current forms a freewheeling circuit along the freewheeling diode in Q3, the freewheeling diode in the exciting coil L, Q and the opening capacitor C2, so as to charge the opening capacitor C2. Because the opening capacitor of the magnetic control mechanism has small energy, the opening capacitor C2 is fully charged after each closing, the opening operation can be effectively realized in the subsequent opening, but because the follow current energy is derived from the energy stored in the inductor in the excitation mechanism, a part of closing energy is lost after Q1 and Q4 are suddenly cut off and cut off, the holding force of the magnetic control mechanism is lost, or a certain demagnetizing is formed, the energy stored in the L in the excitation coil cannot work, but is converted into the energy storage and heating consumption of the opening capacitor C2, the closing strategy cannot lead the magnetic control mechanism to fully exert the maximum magnetic attraction force, the holding force of the magnetic control mechanism is not ideal in engineering practice, Fig. 2 shows a closing current voltage waveform in this technology, wherein ① is a voltage actual measurement curve, ② is a current actual measurement curve, and the voltage curve can clearly show the reverse induced electromotive forces occurring after Q1 and Q4 are turned off.

Disclosure of utility model

In order to overcome the defects in the prior art, the utility model provides an improved H-bridge control circuit suitable for controlling a breaker operating mechanism, so as to improve or ensure the closing holding force of the monostable breaker operating mechanism after closing action is completed.

The technical scheme of the utility model is as follows: the improved H-bridge control circuit comprises an opening and closing H-bridge control circuit of a circuit breaker operating mechanism, wherein the load of the H-bridge control circuit is an exciting coil of the circuit breaker operating mechanism, the improved H-bridge control circuit also comprises an auxiliary opening and closing control circuit, the auxiliary opening and closing control circuit is provided with a switching element, the input end of the switching element is connected with an energy storage element, and the auxiliary opening and closing control circuit is connected with the upper arm of an opening and closing control branch of the H-bridge control circuit in parallel.

Preferably, the switching element is a GTO (gate turn-off thyristor), a MOSFET (field effect transistor), an IGBT (insulated gate bipolar transistor), a relay, or a contactor (quick contactor).

The energy storage element can adopt an electrolytic capacitor, can adopt other energy storage components suitable for realizing an energy storage function in a circuit, and can also adopt a (large multiplying power) discharge battery.

The number of the energy storage elements can be one, and in order to better realize the purpose of opening the brake, the number of the energy storage elements can also be a plurality of the energy storage elements, and when the number of the energy storage elements is a plurality of the energy storage elements, the plurality of the energy storage elements are connected in parallel.

Preferably, the control terminal of the switching element is connected in series with a protection resistor, and the resistance value of the protection resistor is usually several ohms.

Preferably, a transient suppression element or a protection loop is connected between the control end and the output end (or ground end) of the switching element, so as to prevent the switching element from being damaged by overvoltage.

The transient suppression element may be a TVS (transient voltage suppression diode) and the protection circuit may be a CRD (constant current diode) suppression circuit.

In order to meet the existing switching current parameters, the number of the H-bridge control circuits may be a plurality (for example, two or three), and the exciting coils are adopted as a common load by the H-bridge control circuits (i.e., the H-bridge control circuits are connected in parallel to the exciting coils).

Corresponding switching elements for realizing the same function in the H-bridge control circuits connected in parallel can be controlled independently or uniformly.

The H bridge control circuit comprises a switching-on control branch and a switching-off control branch, the number of the switching-off control branch can be one or a plurality of (for example, two or three), when the number of the switching-off control branch is a plurality of, the upper arms of the plurality of switching-off control branches are connected in parallel, and the lower arms of the plurality of switching-off control branches are connected in parallel.

The number of the auxiliary brake-separating control circuits can be one, and in order to meet the current parameter requirement when the auxiliary brake-separating control circuits are used for controlling the breaker operating mechanism to execute brake-separating action, the number of the auxiliary brake-separating control circuits can also be a plurality of the auxiliary brake-separating control circuits.

The switching elements in the auxiliary switching-off control circuits can be controlled independently, are provided with respective control ends, and can also be provided with a shared control end for unified control.

The switching-on/off H-bridge control circuit of the breaker operating mechanism is provided with a switching element (which can be a single switching element or a circuit formed by multiple elements for executing a switching function, such as corresponding ICs) and a coil (such as an exciting coil or exciting coil of the breaker operating mechanism), wherein the switching element comprises a first switching element, a second switching element, a third switching element and a fourth switching element, the first switching element, the second switching element, the third switching element, the fourth switching element and the exciting coil form an H-bridge (H-bridge circuit or H-bridge structure), or are mutually connected into an H-bridge, the first switching element and the third switching element are connected in series to form one side branch of the H-bridge, the second switching element and the fourth switching element are connected in series to form a branch circuit of the other side of the H bridge, the coil is an exciting coil of an operating mechanism of the monostable breaker and is used as a load branch circuit in the H bridge, two ends of the coil are respectively connected to the middle parts of the two side branches, the outer end (or called input end) of the first switching element is connected with a first capacitor serving as a switching-on upper arm (or called upper arm of a switching-on control branch circuit) in the circuit, the outer end of the second switching element is connected with a second capacitor serving as a switching-off upper arm (or called upper arm of a switching-off control branch circuit) in the circuit, and the second capacitor is connected with the outer end of the second switching element to form a switching-off upper arm (or main switching-off upper arm of the switching-off control branch circuit).

The switching element of the auxiliary switching-off control circuit is used as a fifth switching element, the energy storage element is used as a fifth capacitor to be connected with the H-bridge control circuit to form an improved H-bridge control circuit suitable for the control of the breaker operating mechanism, and the fifth switching element and the second switching element are connected in parallel (connected with the fourth switching element in a mode of being connected with the second switching element in parallel).

Preferably, the switching elements are identical (are identical elements).

Preferably, the control end of the switching element in the H-bridge control circuit is connected in series with a protection resistor.

Preferably, the protection resistances of the control ends of the switching elements in the H-bridge control circuit are identical.

Preferably, the capacitance of the second capacitor is smaller than the capacitance of the first capacitor.

Preferably, the second capacitance and the fifth capacitance are the same (are the same capacitance).

Preferably, at least the third switching element and the fourth switching element in the H-bridge control circuit are provided with freewheeling diodes.

Preferably, a transient voltage suppression diode is connected between the ground side (or ground terminal, a connection terminal for connecting to ground directly or through other elements, such as the source of a MOSFET) and the control terminal (a connection terminal for connecting to ground directly or through other elements, or for accessing a control signal/level, such as the gate of a MOSFET) of the switching element in the H-bridge control circuit.

The utility model discloses can adopt following monostable circuit breaker operating mechanism control strategy (or call control method) to carry out monostable circuit breaker operating mechanism's control/operation: the first capacitor is used for discharging to implement switching-on operation, after the switching-on (switching-on operation) is completed, only the first switching element is turned off, the fourth switching element is temporarily not turned off, under the condition that the second capacitor stores energy (electric quantity/voltage) fully, the second capacitor or the fifth capacitor is used for discharging to implement switching-off operation, and under the condition that the second capacitor does not store energy fully, the fifth capacitor is used for discharging to implement switching-off operation.

After closing, the fourth switching element is kept in an on state at least during discharging of the exciting coil (i.e. after closing, only the first switching element is turned off, and the fourth switching element is temporarily turned off). The fourth switching element may be turned off after the end of the discharge of the exciting coil, or may be turned off before the subsequent opening.

Further, before the opening operation, the energy storage condition of the second capacitor is detected.

The energy storage condition of the second capacitor may be detected in any suitable manner.

For example, a timer is set, the timing duration of the timer is set according to the charging duration of the second capacitor, when the discharging of the second capacitor is terminated, the timer is started to count, before the next opening operation, whether the timer overflows or not is detected, if so, the opening operation is implemented by discharging the second capacitor, if not, and the opening operation is implemented by discharging the fifth capacitor.

For another example, a second capacitor voltage detection circuit is provided, before the opening operation, voltage information/data of the second capacitor is obtained through the second capacitor voltage detection circuit, for example, the second capacitor voltage meets the discharge requirement (with voltage required by effectively implementing the opening operation), the opening operation is implemented by discharging the second capacitor, for example, the second capacitor voltage does not meet the discharge requirement (without voltage required by effectively implementing the opening operation), and the opening operation is implemented by discharging the fifth capacitor.

For example, in a general case, when the rated operation sequence of the circuit breaker is O-0.3S-CO-180S-CO, the second switching operation in the rated operation sequence O-0.3S-CO-180S-CO may be performed using the fifth capacitor as a discharge capacitor, and the second capacitor may be used as a discharge capacitor to perform other switching operations than the second switching operation.

The specific control/operation modes can be as follows:

In the initial state, each switching element in the improved H-bridge control circuit may be in an off state.

When the switching-on/switching-on operation is performed, Q2, Q3 and Q5 are ensured to be in a switching-off state (the switching-off state is kept, or the switching-on state is changed into the switching-off state), Q1 and Q4 are opened (synchronously switched on) (the switching-off state is changed into the switching-on state of Q1 and Q4), the discharging circuit (which can be called as a switching-on circuit) of C1 is formed by connecting C1, Q1 and L, Q4 with ground, the discharging (current) of C1 flows through L, the circuit breaker executes the switching-on operation, after the switching-on operation is completed, Q1 is disconnected, Q4 is kept in the switching-on state, and Q1 is switched off at any time after the discharging of L is completed to the subsequent switching-off state.

When the second capacitor discharges to perform the opening operation, Q1, Q4 and Q5 are ensured to be in an off state, then Q2 and Q3 are opened (synchronously opened) (Q2 and Q3 are changed from the off state to the on state), so that C2, Q2 and L, Q are connected with ground to form a discharging loop (which can be called an opening loop or a main opening loop) of C2, and the discharging (current) of C2 flows through L, so that the circuit breaker performs the opening operation, and then Q2 and Q3 are disconnected (synchronously opened).

When the fifth capacitor discharges to perform the opening operation, Q1, Q2 and Q4 are ensured to be in an off state, then Q3 and Q5 are opened (synchronously opened) (Q3 and Q5 are changed from the off state to the on state), C5, Q5 and L, Q are connected with ground to form a discharging loop (which can be called an auxiliary opening loop or a standby opening loop) of C5, and discharging (current) of C5 flows through L to enable the circuit breaker to perform the opening operation, and then Q3 and Q5 are disconnected (synchronously opened).

The beneficial effects of the utility model are as follows: because the auxiliary brake-separating control circuit is arranged, the brake-separating operation can be performed by the auxiliary brake-separating control circuit under the condition that the main brake-separating capacitor C2 is insufficiently charged (the electric quantity is insufficient). When the control strategy is used for controlling/operating the monostable breaker operating mechanism, the control/operating strategy of the monostable breaker operating mechanism is allowed to be adopted, reverse electromotive force is not generated, the phenomenon that the main brake-separating capacitor C2 cannot be used for separating brake due to insufficient electric quantity caused by lack of reverse electromotive force charging is avoided, and further full conversion of brake-closing energy can be realized under the control strategy, so that magnetic force of the magnetic control mechanism is reserved or increased. Through actual measurement, the monostable breaker operating mechanism is controlled under the corresponding control strategy, and under the condition that the magnetic control mechanism is not saturated, the closing holding force is increased by 10 to 15 percent compared with the prior art, so that the closing reliability is effectively improved/ensured.

Drawings

FIG. 1 is a schematic diagram of a prior H-bridge control circuit for a monostable breaker operating mechanism;

Fig. 2 is a waveform diagram of a closing current and voltage of the conventional H-bridge control circuit shown in fig. 1 under a corresponding control strategy, wherein a curve ① is a voltage actual measurement curve, and a curve ② is a current actual measurement curve;

FIG. 3 is a schematic diagram of one embodiment of an improved H-bridge control circuit in accordance with the present utility model;

fig. 4 is a waveform diagram of a closing current and voltage according to the embodiment of the present utility model shown in fig. 3 under a corresponding control strategy, wherein a curve ① is a voltage measured curve, and a curve ② is a current measured curve.

Detailed Description

Referring to fig. 3, the present utility model may be used in monostable circuit breaker operating mechanism control (or operation) or other similar applications to operate a circuit breaker to perform closing and opening actions by providing closing and opening currents to the exciting coil of the circuit breaker operating mechanism. The switching element of the improved H-bridge circuit comprises a first switching element Q1, a second switching element Q2, a third switching element Q3, a fourth switching element Q4 and a fifth switching element Q5, the basic parts of the switching element are a conventional H-bridge structure (a switching-on/off H-bridge control circuit of a breaker operating mechanism), the switching element mainly comprises the first switching element Q1, the second switching element Q2, the third switching element Q3 and the fourth switching element Q4, wherein the first switching element Q1 and the third switching element Q3 are connected in series to form one side branch of the H-bridge, the second switching element Q2 and the fourth switching element Q4 are connected in series to form the other side branch of the H-bridge, the first switching element Q1 and the second switching element Q2 are respectively positioned at the power supply side (the connection side with the positive electrode of a power supply/a power supply in the H-bridge), the first capacitor C1 used as a switching energy storage capacitor and the second capacitor C2 used as a switching energy storage capacitor are respectively connected, the other ends of the first capacitor C1 and the second capacitor C2 are grounded (connected with the ground/common reference), the third switching element Q3 and the fourth switching element Q4 are respectively positioned at the grounding side of the branch where each is positioned (the connecting side with the ground/power supply cathode in the H bridge) and grounded, the exciting coil is used as a load branch in the H bridge, the two ends of the exciting coil are respectively connected to the middle parts of the two side branches (between the two switching elements in the branch), the middle part of the branch can be used as a boundary, the part connected with a power supply (or a power supply anode) is called an upper arm, the part connected with the ground (or a power supply cathode) is called a lower arm, under the H bridge structure, the two upper arms are respectively composed of the first switching element Q1 and the second switching element Q2, the two lower arms are respectively formed by a third switching element Q3 and a fourth switching element Q4. The first capacitor C1 and the second capacitor C2 respectively form a power source connected to the two upper arms. For convenience in description, the upper arm (corresponding switching element) of the H-bridge and the connected capacitor may be referred to as an upper arm of the circuit, wherein the upper arm formed by the first switching element Q1 and the first capacitor C1 may be referred to as a closing upper arm (upper arm of the closing control branch), the upper arm formed by the second switching element Q2 and the second capacitor C2 may be referred to as a opening upper arm or a main opening upper arm (upper arm of the opening control branch), and correspondingly, the lower arm of the H-bridge may be referred to as a closing lower arm (lower arm of the closing control branch) and an opening lower arm (lower arm of the opening control branch), respectively.

For such a conventional H-bridge, in the case where Q1 and Q4 are on (Q2 and Q3 are off), the first capacitor C1 is discharged, an exciting current (which may be called a forward current) is formed in the exciting coil, and the circuit breaker performs a closing operation; when Q2 and Q3 are on (Q1 and Q4 are off), the second capacitor C2 discharges, a reverse current is formed in the exciting coil, the closing holding force of the circuit breaker is eliminated, and the circuit breaker performs a breaking action under the action of an internal spring (or other member).

Since the rated operating sequence of the interrupter is typically O-0.3S-CO-180S-CO, or other similar reclosing actions are performed, under the control strategy involved in the present utility model, if only a conventional H-bridge is provided, it is difficult to ensure that C2 has sufficient power after reclosing due to the absence (substantial absence) of a counter electromotive force capable of charging C2. Therefore, the utility model improves the conventional H bridge, an auxiliary switching upper arm (or called a standby switching upper arm or an auxiliary switching control circuit) which is parallel to (in parallel with) a main switching upper arm formed by Q2 and C2 is arranged, the auxiliary switching upper arm comprises a fifth switching element Q5 and a fifth capacitor C5 which is used as an auxiliary switching energy storage capacitor (or called a standby switching energy storage capacitor), the fifth switching element Q5 is connected with a fourth switching element Q4 like a second switching element Q2 to form a parallel connection with the second switching element, thereby the fifth switching element, the first switching element Q1, a third switching element Q3 and the fourth switching element Q4 also form an H bridge structure, the fifth capacitor C5 is connected to the power supply side (or called the outer end) of the fifth switching element Q5 and grounded, and under the condition that the Q5 and Q3 are conducted, the fifth capacitor C5 discharges to form reverse current at an exciting coil, and then the switching action of the breaker is implemented. Therefore, for the operating mechanism, the effect of the fifth capacitor discharge and the second capacitor discharge is the same, and when the energy storage in the second capacitor C2 is insufficient, the discharge loop of the fifth capacitor C5 can be turned on to realize the opening.

The switching on and off of the switching elements can be controlled according to the prior art, for example, when a MOSFET is used as the switching element (see fig. 3), the MOSFET is switched on at a high level and switched off at a low level at the gate of the MOSFET.

The corresponding control outputs of the control device/controller (e.g., MCU, not shown) may be connected to the control terminals of the switching elements, respectively, to control the on/off of the switching elements. Wherein the control outputs CLOSE1 and CLOSE2 that are connected to Q1, Q4 may be referred to as closing control outputs, and in the embodiment shown in fig. 3, Q1 or Q4 is turned on (opened) when CLOSE1 or CLOSE2 is at a high level; when CLOSE1 or CLOSE2 is low, Q1 or Q4 is off. The control outputs TRIP1, TRIP2 and TRIP3 of the access Q2, Q3, Q5 may be referred to as the split control outputs, further TRIP1 may be referred to as the main split control output, TRIP3 may be referred to as the auxiliary (standby) split control output, Q2, Q3 or Q5 is turned on (turned on) when TRIP1, TRIP2 or TRIP3 is high, and Q2, Q3 or Q5 is turned off when TRIP1, TRIP2 or TRIP3 is low. Therefore, when the closing loop needs to be opened, CLOSE1 and CLOSE2 may be set to high level, TRIP1, TRIP2 or TRIP3 may be set to low level; when the main switching-off loop needs to be opened, TRIP1 and TRIP2 can be set to be in a high level, and TRIP3, CLOSE1 and CLOSE2 can be set to be in a low level; when the auxiliary (standby) switching-off loop needs to be opened, TRIP2 and TRIP3 may be set to high level, TRIP1, CLOSE1 and CLOSE2 may be set to low level.

The switching element may be IGBT, MOSFET, GTO or other elements with similar functions, and may be referred to as a switching tube, and IGBT, MOSFET, GTO or other elements with similar functions used as a switching tube are usually provided with a freewheeling diode, which may be built in the switching tube or may be located outside the switching tube (a freewheeling diode separate from the switching tube is used).

D1-D5, which is connected between the ground side of the switching element (the connection terminal for connection to ground/supply negative electrode, e.g. the source of a MOSFET, see fig. 3) and the control terminal (the connection terminal for connection/access of control signal/level to the MCU, e.g. the gate of a MOSFET, see fig. 3), directly or through other elements, etc., is a protection device TVS (TRANSIENT VOLTAGE SUPPRESSOR, transient voltage suppressor, or transient diode), preventing overvoltage damaging the switching tube. R1-R5 connected in series with the control end of the switching element is the gate resistance/gate resistance (protection resistance) of the corresponding switching tube, and also belongs to a protection device, and the resistance is generally several omega.

The charging circuits/modes of charging (not depicted) of C1, C2 and C5 may be set according to the prior art.

When the utility model is used for controlling/operating the operating mechanism of the monostable breaker, the following switching-on strategy (switching-on subprogram) can be implemented:

…

SETB Q2

SETB Q3

SETB Q5；

(turning off the switching elements Q2, Q3, Q5 on each switching circuit)

…

DELAY XXms；

(Proper time delay, ensure that Q5, Q2 and Q3 are reliably turned off, and the duration XX can be according to actual needs)

…

CLR Q1

CLR Q4；

(Two closing switching elements Q1, Q4 for opening a closing Loop)

DELAY XXms；

(Closing pulse time, duration XX may depend on actual needs)

SETB Q1；

(Turning off Q1, when Q4 is not turned off, Q4 remains in the on state)

…

Under the above-described closing subroutine, since the closing lower tube (switching element on the closing lower arm or the lower arm of the closing control branch) Q4 is not turned off, only Q1 is turned off, at which time the closing capacitor is no longer discharged, but since Q4 is turned on, the energy stored in the exciting coil forms a loop along the freewheeling diode of Q3, exciting coils L and Q4 until the current is zero. The switching-on strategy does not generate reverse electromotive force (without substantial influence), all energy in the inductor does work on the mechanism, and as can be seen from the actually measured waveform (as shown in fig. 4, curve ① is a voltage actually measured curve, curve ② is a current actually measured curve), the current does not quickly tend to 0, but gradually decreases, and the current continuously does work on the magnetic control mechanism, so that the magnetic force of the magnetic control mechanism becomes large.

Because the switching-on strategy cannot realize the charge of the switching-off capacitor C2 through the cooperation of the reverse electromotive force, the switching-off capacitor C2 cannot meet the switching-off requirement after reclosing in the charging time formed by short delay, and therefore, in order to realize the second switching-off requirement in the rated operation sequence O-0.3S-CO-180S-CO of the circuit breaker, C5 can be used as a discharge capacitor, and switching-off operation can be implemented through the discharge of a standby discharge loop formed by C5, Q5, L, Q and ground. The electric quantity condition of the brake-separating capacitor C2 can be obtained through timer overflow judgment and hardware circuit detection, so that whether an auxiliary discharging (brake-separating) loop or a main discharging (brake-separating) loop is adopted or not is determined, and the main brake-separating loop can be preferentially adopted under the condition that both the auxiliary discharging (brake-separating) loop and the main discharging (brake-separating) loop can be effectively separated.

The corresponding opening strategy may be: setting a timer (the time length of the timer is determined according to the charging time of the opening capacitor C2) in the opening sub-program, and starting a standby opening loop if the timer is detected to not overflow (a hardware detection mode can be adopted to detect whether the opening capacitor C2 has enough energy storage or not, and if the opening capacitor C2 has not enough energy storage); if the timer overflows (or the opening capacitor C2 has enough energy storage), the main opening lockage sequence (the opening procedure of discharging the capacitor C2 to provide reverse current, or the opening procedure of the main opening loop) can be adopted. That is, detecting the time overflow flag bit of the timer, if no overflow exists, jumping to the standby brake-separating sub-program (otherwise jumping to the main brake-separating program); or the detection hardware C2, such as the undercharged (reaching the set voltage), jumps to the standby switching-off subroutine (otherwise jumps to the main switching-off routine).

The standby brake release subroutine may include the steps of:

…

CJNE TIMER_FLAG,TRIP_BACKUP；

(detecting time overflow flag bit, if no overflow, jump to standby brake-separating sub-process, if overflow, go to main brake-separating process)

JMP MAIN_TRIP

(Above is flag bit detection, hardware may also be detected:

JNB C2_Capacitor,TRIP_BACKUP

(the underfill jumps to the alternate opening subroutine, otherwise to the main opening routine)

JMP MAIN_TRIP)

TRIP_BACKUP:

SETB Q2

SETB Q1

SETB Q4；

(Turning off the main brake-separating upper arm tube Q2 and the brake-closing loop tubes Q1, Q4)

…

DELAY XXms；

(Proper time delay, reliable turn-off is ensured, and the duration XX can be according to actual needs)

…

CLR Q5

CLR Q3；

(Opening auxiliary brake-separating loop)

DELAY XXms；

(The break-in pulse time, the duration XX can be according to the actual need)

SETB Q5

SETB Q3；

(Switching off the switching tubes Q3, Q5 of the auxiliary brake-separating loop)

…

Fig. 2 and 4 show the change curves of the switching current and voltage of the improved H-bridge control circuit according to the present utility model under the same conditions and under the corresponding control strategy, and the change curves of the switching current and voltage of the prior art (using the H-bridge control circuit shown in fig. 1 under the corresponding prior control strategy), respectively, fig. 2 shows the obvious back electromotive force caused by switching on, and fig. 4 shows the back electromotive force without that shown in fig. 2.

The preferred and optional technical means disclosed in the present utility model may be arbitrarily combined to form a plurality of different specific embodiments unless otherwise specified and when one preferred or optional technical means is further defined as another technical means.

Claims (10)

1. The improved H-bridge control circuit is characterized by further comprising an auxiliary brake-separating control circuit, wherein the auxiliary brake-separating control circuit is provided with a switching element, the input end of the switching element is connected with an energy storage element, and the auxiliary brake-separating control circuit is connected with the upper arm of a brake-separating control branch of the H-bridge control circuit in parallel.

2. An improved H-bridge control circuit adapted for circuit breaker operating mechanism control as in claim 1 wherein said switching element is GTO, MOSFET, IGBT, a relay or a contactor.

3. An improved H-bridge control circuit adapted for circuit breaker operating mechanism control as in claim 1 wherein said energy storage element is an electrolytic capacitor or a discharge battery.

4. The improved H-bridge control circuit adapted for circuit breaker operating mechanism control of claim 1 wherein said number of energy storage elements is a plurality, said plurality of energy storage elements being connected in parallel.

5. An improved H-bridge control circuit adapted for circuit breaker operating mechanism control as in claim 1 wherein said switching element control terminal is connected in series with a protection resistor.

6. An improved H-bridge control circuit adapted for control of a circuit breaker operating mechanism as in claim 1 wherein a transient suppression element or protection circuit is connected between the control terminal and the output terminal of said switching element.

7. The improved H-bridge control circuit adapted for circuit breaker operating mechanism control of claim 1 wherein said H-bridge control circuits are a number of said H-bridge control circuits, said H-bridge control circuits employing said exciting coils as a common load.

8. The improved H-bridge control circuit for circuit breaker operating mechanism control of claim 1, wherein said H-bridge control circuit comprises a closing control branch and a breaking control branch, said breaking control branch being a number of said breaking control branches, upper arms of said breaking control branches being connected in parallel, and lower arms of said breaking control branches being connected in parallel.

9. The improved H-bridge control circuit adapted to control a circuit breaker operating mechanism as recited in any one of claims 1-8 wherein the number of said auxiliary brake-off control circuits is a number, said number of auxiliary brake-off control circuits being in parallel with the upper arms of the brake-off control legs of the H-bridge control circuits.

10. An improved H-bridge control circuit adapted for circuit breaker operating mechanism control as in claim 9 wherein the switching elements in a plurality of said auxiliary switching control circuits are provided with a common control terminal.