JP6136140B2 - Motor control device and electric pump unit - Google Patents

Description

  The present invention relates to a motor control device and an electric pump unit, and more particularly to a motor control device for an electric pump unit suitable for supplying hydraulic pressure to an automobile transmission and an electric pump unit including such a motor control device.

  As a device for supplying hydraulic pressure to an automobile transmission, a device having only a main pump driven by an engine as a main power source has been used.

  However, when an idle stop function is provided that stops the engine when the vehicle is stopped, the conventional main pump and battery are connected to ensure the supply of hydraulic pressure to the drive system such as the transmission even when the engine is stopped due to the idle stop. Two hydraulic sources are required, with an auxiliary pump driven by an electric motor as a power source. As a hydraulic pressure supply device for a transmission provided with such two hydraulic pressure sources, the one shown in Patent Document 1 is known. This hydraulic pressure supply device supplies hydraulic pressure to the transmission, and the auxiliary pump constitutes an electric pump unit together with an electric motor and a motor control device for driving the auxiliary pump. When the oil pressure in the main discharge oil passage from the main pump to the transmission is above a predetermined value, the drive of the auxiliary pump is stopped, and when the oil pressure in the main discharge oil passage is less than the predetermined value, the auxiliary pump is driven. ing. Here, the hydraulic pressure supplied by the main pump is several tens of times larger than the hydraulic pressure supplied by the auxiliary pump, and the measurement range of the hydraulic sensor is set according to the hydraulic pressure supplied by the main pump. Therefore, if this is used for the hydraulic control of the auxiliary pump, the measurement accuracy is not sufficient and the hydraulic control is difficult. When the auxiliary pump is driven, a target hydraulic pressure or higher is obtained by driving the electric motor based on the current command value from the host ECU.

JP 2010-116914 A

 In the above-described conventional electric pump unit, since the drive according to the current command value is performed regardless of whether or not there is a load on the electric motor, an excessively large output (over output) state is generated, which also saves energy. Also, it is not preferable in terms of heat generation and noise generation. In order to suppress the excessive output, it is preferable to obtain the actual oil pressure and control based on the actually measured oil pressure. To that end, a hydraulic sensor with a low measurement range is used for the electric pump unit, in addition to the main pump. There is a problem that it needs to be added and the cost becomes high. Therefore, in order to suppress the excessive output, it is necessary to accurately estimate the hydraulic pressure of the pump so that the hydraulic sensor for the electric pump unit does not need to be added. In this case, the viscosity of the oil changes depending on the temperature. Therefore, how to handle this also becomes a problem.

  The object of the present invention is to solve the above problems and suppress overpower, thereby suppressing heat generation and noise to a minimum, and motor control that does not require the addition of a hydraulic sensor for suppressing overpower An apparatus and an electric pump unit are provided.

A motor control device according to the present invention includes a control circuit provided with a control signal output means for outputting a motor control signal, and a drive circuit that operates in response to the input of the motor control signal and supplies drive power to the electric motor. In the motor control device that controls the electric motor that drives the pump that sucks and discharges oil based on the hydraulic pressure, the control circuit suppresses the excessive output by reducing the current command value from the host control device. An overpower suppression control unit is further provided, and the control signal output unit adds the reduction amount of the current command value obtained by the overpower suppression control unit to the current command value from the host controller, and outputs the motor control signal. The overpower suppression control means has a hydraulic pressure estimation calculation unit that estimates a hydraulic pressure based on at least a current and a rotation speed of the electric motor, a target hydraulic pressure, an estimated hydraulic pressure, And a current command value correction amount calculation unit that outputs a reduction amount of the current command value to the control signal output means when the estimated hydraulic pressure is high. The hydraulic pressure estimation calculation unit includes a current and a rotation speed of the electric motor. A hydraulic pressure estimation map or hydraulic pressure estimation calculation formula showing the correspondence between the oil pressure and the estimated hydraulic pressure is set, and the individual hydraulic pressure estimated from the oil temperature, oil flow rate and estimated hydraulic pressure is added to the current command value correction amount calculation section Table data of the oil temperature and the required motor speed corresponding to the load curve of the device to be set is set, the current command value correction amount calculation unit lowers the current value when the estimated oil pressure is larger than the target oil pressure, At this time, the motor speed is set so as not to fall below the required motor speed of the table data.

  In the overpower suppression control means, a reduction amount of the current command value from the host control device is obtained, and the motor control signal output from the control signal output means adds this reduction amount to the current command value from the host control device. It will be. The excessive output suppression control means outputs a reduction amount of the current command value to the control signal output means when the estimated oil pressure is high, based on the preset target oil pressure and the estimated oil pressure that changes by being driven by the electric motor. Thus, compared to control based on the current command value from the host controller, the actual hydraulic pressure can be lowered while the target hydraulic pressure is secured, and the output of the electric motor can be suppressed.

  The actual hydraulic pressure is preferably estimated from the data obtained by the electric motor so that the hydraulic sensor for the electric pump unit does not need to be added, and at least the electric motor current and the rotational speed (only these two are used. The hydraulic pressure may be estimated by a hydraulic pressure estimation calculation unit that estimates the hydraulic pressure from the reference voltage and the power supply voltage, if necessary. When estimating the oil pressure, the estimated value changes depending on the oil temperature, that is, the viscosity of the oil. By correcting the estimated oil pressure value or the target oil pressure value based on the oil temperature information (while keeping the target oil pressure at the set value) The estimated oil pressure may be corrected based on the oil temperature information, and conversely, the set value of the target oil pressure may be corrected based on the oil temperature information), and the accuracy of the overpower suppression control is improved.

  In this way, control to achieve an appropriate output (no shortage of required output and no excessive output) is performed without adding a hydraulic pressure sensor for suppressing excessive output, and heat generation and noise can be minimized.

  When correcting the estimated oil pressure based on the oil temperature information, using the oil pressure estimation map or oil pressure estimation formula corresponding to multiple oil temperature zones, the oil pressure estimation accuracy can be increased and the overpower suppression control accuracy can be improved. Enhanced.

  Also, by setting the required motor speed based on a load curve (curve obtained in advance) that shows the relationship between the required oil pressure and the required flow rate, the required flow rate for each load and oil temperature can be set. Secured.

  An electric pump unit according to the present invention includes a pump that performs suction and discharge of oil, an electric motor for driving the pump, and a motor control device that controls the electric motor based on hydraulic pressure. Is characterized in that it is as described above.

  According to the electric pump unit of the present invention, as described above, the hydraulic pressure is accurately estimated, and the actual hydraulic pressure can be lowered while ensuring the target hydraulic pressure. Control to reduce heat generation and noise due to excessive output to a minimum, and in particular, by making sure that the motor speed does not fall below the required motor speed in the table data, The accuracy of securing the required flow rate for each is improved.

FIG. 1 is a schematic configuration diagram showing an embodiment in which the electric pump unit of the present invention is applied to a hydraulic pressure supply device for an automobile transmission. FIG. 2 is a block diagram showing an example of a schematic configuration of hardware of the motor control device of the present invention. FIG. 3 is a block diagram showing an example of a schematic configuration of software of the motor control device of the present invention. FIG. 4 is a graph showing a typical example of a hydraulic pressure-flow rate curve which is an output characteristic of a pump obtained by the motor control device of the electric pump unit of the present invention. FIG. 5 is a graph showing the output characteristics of the pump obtained by the motor control device of the electric pump unit of the present invention. FIG. 6 is a diagram showing an example of table data used by the motor control device of the electric pump unit according to the present invention.

  Hereinafter, an embodiment in which the present invention is applied to a hydraulic pressure supply device for an automobile transmission will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram illustrating an example of a hydraulic pressure supply device that supplies hydraulic pressure to a transmission (continuously variable transmission) of an automobile.

  In FIG. 1, the hydraulic pressure supply device is provided with an electric pump unit (1) for transmission. This electric pump unit (1) is used for auxiliary supply of hydraulic pressure that decreases during idle stop in the transmission (2) of an automobile, and includes a pump (3) that is an auxiliary pump for hydraulic supply, and a pump A drive electric motor (4) and a motor control device (5) for controlling the motor (4) are provided.

  The motor (4) is a sensorless control brushless DC motor, and the auxiliary pump (3) is an internal gear pump. Preferably, the pump (3) and the motor (4) are integrally provided in a common housing. The motor control device may also be provided in a common housing with the pump (3) and the motor (4).

  In addition to the electric pump unit (1) having the auxiliary pump (3), the hydraulic pressure supply device is provided with a main pump (7) driven by the engine (6).

  The oil suction port (8) of the main pump (7) is connected to the oil pan (9), and the oil discharge port (10) is connected to the transmission (2) via the main discharge oil passage (11). The oil suction port (12) of the auxiliary pump (3) is connected to the oil pan (9), and the oil discharge port (13) is connected to the main discharge oil passage (11) via the auxiliary discharge oil passage (14). Yes. The auxiliary discharge oil passage (14) is provided with a check valve (15) that prevents backflow of oil from the main discharge oil passage (11) side to the auxiliary pump (3). The main discharge oil passage (11) is provided with a hydraulic pressure sensor (16) and an oil temperature sensor (17).

  The motor control device (5) is connected to a battery (18) as a DC power source and a host ECU (upper control device) (19) which is a computer for controlling the engine (6) and the transmission (2). The host ECU (19) monitors the oil pressure in the main discharge oil passage (11) from the output of the oil pressure sensor (16), and when the oil pressure is above a predetermined set value, the auxiliary pump stop signal is displayed. The auxiliary pump drive signal is output to the motor controller (5).

  When the auxiliary pump stop signal is output from the host ECU (19), the motor control device (5) stops driving the motor (4) and stops driving the auxiliary pump (3). When the drive signal is output, the motor (4) is driven to drive the auxiliary pump (3).

  When the engine (6) is driven, the main pump (7) is driven by this, and normally the hydraulic pressure in the main discharge oil passage (11) is higher than the set value, and the auxiliary pump (3) stops driving. doing. At this time, oil is supplied from the main pump (7) to the transmission (2) via the main discharge oil passage (11). The check valve (15) prevents the backflow of oil from the main discharge oil passage (11) to the auxiliary pump (3).

  When the engine (6) is stopped, the oil pressure in the main discharge oil passage (11) is generally zero and less than the set value, and the auxiliary pump (3) is driven. Thus, oil is supplied from the auxiliary pump (3) to the transmission (2) through the auxiliary discharge oil passage (14) and the main discharge oil passage (11).

  Even if the engine (6) is driven, if the oil pressure in the main discharge oil passage (11) is less than the set value, the auxiliary pump (3) is driven, and the auxiliary pump (3) to the auxiliary discharge oil passage (14) Oil is supplied to the main discharge oil passage (11) through the.

  When the auxiliary pump (3) is driven, the host ECU (19) instructs the electric pump unit (1) to operate when the idling condition is satisfied, and the motor control device ( 5) controls the motor (4) based on the current command value from the host ECU (19).

  FIG. 2 is a schematic configuration diagram showing one specific example of the hardware of the motor control device (5). The motor control device (5) uses the battery (18) as an internal power source and uses the motor (4) with a one-side PWM method. A CPU (control circuit) (21) having a drive circuit (20) for driving the motor (4), motor control signal output means for controlling the drive circuit (20), and a CPU (21 ) Output a gate drive signal to each switching element constituting the drive circuit (20) based on the motor control signal output from the drive circuit (20), and a current detection circuit for detecting the input current of the drive circuit (20) (23), a phase detection circuit (24) for detecting the phase of the rotor of the motor (4), and a voltage detection circuit (25) for detecting the power supply voltage.

  The hardware configuration shown in FIG. 2 is basically a known configuration, and a known appropriate configuration can be adopted.

  The drive circuit (20) is a switching circuit including a plurality of switching elements (not shown) for controlling energization from the battery (18) to the motor (4). The CPU (21) estimates the rotational position of the rotor (not shown) of the motor (4) from the phase voltage of each phase of the motor (4), and on the basis of this, each switching of the drive circuit (20) is performed by the PWM method. The element is controlled, and thereby energization to the motor (4) is controlled. The current detection circuit (23) detects the input current of the drive circuit (20), and its output is input to the CPU (21). The phase detection circuit (24) detects the phase of the rotor of the motor (4), the output is input to the CPU (21), and is used to determine the rotational speed of the motor (4). The DC voltage of the battery (18) is applied to the drive circuit (20) and the CPU (21), and this becomes the input voltage of the drive circuit (20).

  FIG. 3 shows a software configuration in the CPU (control circuit) (21).

  In the figure, the CPU (21) corrects this based on the current command value from the host ECU (19) and outputs a motor control signal. The CPU (21) 19) A control signal output means (31) for outputting a motor control signal based on a current command value from 19), and an overpower suppression control means for suppressing overoutput by reducing the current command value from the host ECU (19). (32) and minimum output maintenance control means (33) for maintaining the minimum rotation speed for sensorless control by increasing the current command value from the host ECU (19).

  The overpower suppression control means (32) compares the estimated hydraulic pressure obtained by the hydraulic pressure estimation calculation section (34) and the hydraulic pressure estimation calculation section (34) with the target hydraulic pressure, and outputs control signal output from the host ECU (19). A current command value correction amount calculation unit (35) for obtaining a reduction amount of the current command value input to (31).

  The control signal output means (31) obtains a current command value by executing current control, and a voltage command value to which a conversion coefficient is given so that the actual current value follows this current command value is applied to the motor (4). The The control signal output means (31) has a current control loop (37) for performing current feedback control so that the actual current value follows the current command value.

  As will be described later, the overpower suppression control means (32) reduces the current command value from the host ECU (19), and the minimum output maintenance control means (33) is a lower limit for sensorless control. And the actual rotational speed of the motor (4) obtained from the phase of the rotor obtained by the phase detection circuit (24), and when the actual rotational speed of the motor (4) is smaller, The current command value from the host ECU (19) is increased. FIG. 4 shows an auxiliary pump (hereinafter referred to as “pump”) that can be realized by the provision of the overpower suppression control means (32) and the minimum output maintenance control means (33) (3). The characteristics are shown.

  The curves A and B indicated by broken lines in FIG. 4 indicate load curves in consideration of variations in the transmission (2), and A indicates the load at the maximum leakage of the CVT (continuously variable transmission) of the transmission (2). A curve is shown, and B shows a load curve when CVT leakage is minimum. The pump (3) is required to have an output that exceeds the required output point P on the load curve at the time of maximum CVT leakage (required hydraulic value greater than the hydraulic value at point P). The hydraulic pressure-flow rate curve of the pump (3) that can cope with this requires a portion C indicated by a solid line. The pump (3) having such a hydraulic pressure-flow rate curve has a portion indicated by a broken line D in which the flow rate gradually (continuously) decreases as the hydraulic pressure increases unless additional control is performed. Since the portion indicated by the broken line D is larger than the required oil pressure, the oil pressure does not become insufficient in this portion. Output). This excessive output is not preferable in terms of energy saving, heat generation and noise generation.

  Therefore, in the control by the motor control device (5) in the present invention, after the portion of the solid line C (that is, after exceeding the required output point P), the point Q becomes an inflection point and the output is suddenly increased (hydraulic pressure × According to the hydraulic pressure-flow rate curve indicated by the solid line E such that the (flow rate) becomes small. Further, in order to perform sensorless control, the minimum rotational speed of the motor (4) is set, and the minimum curve portion F is set so that a certain amount of flow is ensured even when the hydraulic pressure is large.

  Variations in the transmission (2) are taken into account by controlling the motor (4) so that the output of the pump (3) becomes a hydraulic-flow rate curve consisting of a solid line C, a solid line E and a solid line F having an inflection point Q. Thus, the required output is satisfied even with respect to the upper limit of the dispersion of the transmission (2), and control can be performed so as not to cause excessive output.

  In the hydraulic pressure-flow rate curve shown in FIG. 4, the inflection point Q of the excessive output suppression is moved by changing the estimated hydraulic pressure due to individual differences such as the efficiency of the pump (3) and the torque constant of the motor (4). Therefore, when the hydraulic pressure estimation map (36) is common to all electric pump units (1), the inflection point Q is insufficient when the inflection point Q is small, and the inflection point Q is large. Becomes over output and disadvantageous to heat generation and noise.

  Therefore, the output of the electric pump unit (1) is measured for each product, and an offset gain (adjustment coefficient) for each electric pump unit (1) is obtained. The offset gain is obtained, for example, as a constant (1.02, 0.97, etc.) for multiplying the estimated value of the hydraulic pressure and stored in the CPU (21) of the motor control device (5) of each electric pump unit (1). Is done. Then, a value obtained by correcting the estimated value of the hydraulic pressure obtained from the hydraulic pressure estimation map (36) by the offset gain is output from the hydraulic pressure estimation calculation unit (34) to the current command value correction amount calculation unit (35).

  The hydraulic pressure is estimated by the power supply current (or motor current) of the electric pump unit (1) and the motor rotation speed, instead of using the value detected by the hydraulic sensor (16) in the main discharge oil passage (11). Yes. More specifically, using the oil temperature obtained from the host ECU (19), the power source current (or motor current) obtained in the electric pump unit (1), the motor rotation speed, and the power source voltage, the hydraulic pressure estimation calculation unit (34 ), The discharge hydraulic pressure is estimated. The hydraulic pressure estimation calculation unit (34) has a motor rotation speed and current data table (hydraulic pressure estimation map (36)), and the estimated hydraulic pressure is obtained by applying the reference voltage and power supply voltage of the data table to the values applied to the data table. It is obtained as a value multiplied by the ratio.

  The hydraulic pressure estimation map (36) is stored in the CPU (21), and when an operation instruction is issued from the host ECU (19) to the electric pump unit (1), the estimated hydraulic pressure obtained from the hydraulic pressure estimation map (36) The motor (4) is controlled so that becomes the target hydraulic pressure. The target hydraulic pressure is determined so as to satisfy the hydraulic pressure-flow rate curve composed of the solid line C, the solid line E, and the solid line F shown in FIG. 4, so that overpower suppression control that saves energy and suppresses generation of heat and noise can be performed. Executed.

  In the above control, since the estimation error when estimating the oil pressure is large, the required flow rate cannot be secured by the control based on the oil pressure estimation map (36) using the estimated oil pressure (the motor speed is lower than the required speed). There is a fear.

  Therefore, in the motor control device (5), table data (38) of necessary motor speed obtained from a load curve obtained in advance is set.

  The load curve is estimated from the oil temperature, the oil flow rate, and the estimated oil pressure. The load curve thus obtained is shown in FIG. 5 between a load curve A at the maximum CVT leakage of the transmission (2) and a load curve B at the minimum CVT leakage. To position. For the pump (3) attached to the transmission (2) by dividing the load curve A between the maximum time and the load curve B at the minimum time into load curve 1, load curve 2, etc. A load curve corresponding to each transmission (2) is set. By using this load curve G, the required flow rate can be obtained from the required oil pressure, and R is obtained as the required output point required for each pump (3). If the required flow rate is known, the required motor speed can be calculated. As for the required motor speed, as shown in FIG. 6, the required motor speed is set for each oil temperature for each of the load curves 1 to N (N is an appropriate number of 2 or more).

  In this way, by setting the required motor speed and making sure that the target motor speed does not fall below the required motor speed in the table data, the required flow rate for each load and oil temperature is secured, and the hydraulic pressure is insufficient. Is prevented.

  In addition, it can obtain | require as required rotation speed = required flow volume x pump basic discharge amount x pump volumetric efficiency. Since the load curve changes with time, it is preferable to update the load curve periodically.

  In the above, a hydraulic pressure estimation calculation formula using the oil temperature, power supply current (or motor current), motor rotation speed, and power supply voltage is stored in the hydraulic pressure estimation map (36). The hydraulic pressure can also be estimated based on

  As for the oil temperature information, as shown in FIG. 1, an oil temperature sensor (17) is provided in the main discharge oil passage (11), and the host ECU (19) supervising the idling stop monitors the oil temperature information. Therefore, the oil temperature information is sent from the host ECU (19) to the electric pump unit (1), and the oil pressure estimation map (36) is switched based on the oil temperature information. The oil temperature information at this time may be any one of low temperature, medium temperature, and high temperature, for example.

  The number of oil temperature zones is preferably set to three, low temperature, medium temperature, and high temperature as described above, in order to achieve both simplification of calculation processing and ensuring accuracy of estimated hydraulic pressure, but is limited to this. Instead, two or more can be set as appropriate.

  In the above embodiment, the auxiliary pump (3) is switched between driving and stopping based on the hydraulic pressure of the main discharge oil passage (11), but when the engine (6) is driven, the auxiliary pump (3) can be stopped, and the auxiliary pump (3) can be driven when the engine (6) is stopped. The configuration of the electric pump unit (1) is not limited to that of the above embodiment, and can be changed as appropriate. The present invention can also be applied to devices other than a hydraulic pressure supply device for automobile transmissions.

(1): Electric pump unit, (3): Pump, (4): Electric motor, (19): Host ECU (host controller), (21): CPU (control circuit), (31): Control signal output Means, (32): excessive output suppression control means, (34): hydraulic pressure estimation calculation unit, (35): current command value correction amount calculation unit, (36): hydraulic pressure estimation map, (38): required motor speed Table data

Claims (2)

A control circuit provided with a control signal output means for outputting a motor control signal, and a drive circuit that operates in response to the input of the motor control signal to supply drive power to the electric motor, and sucks and discharges oil. In the motor control device that controls the electric motor that drives the pump that performs the operation based on the hydraulic pressure,
The control circuit further includes an overpower suppression control unit that suppresses overoutput by reducing the current command value from the host controller, and the control signal output unit outputs an overoutput to the current command value from the host controller. The motor control signal is obtained by adding the reduction amount of the current command value obtained by the suppression control means, and the overpower suppression control means estimates the hydraulic pressure based on at least the current and rotation speed of the electric motor. Comparing a calculation unit and a current command value correction amount calculation unit that outputs a reduction amount of the current command value to the control signal output means when the estimated hydraulic pressure is high by comparing the target hydraulic pressure with the estimated hydraulic pressure, and the hydraulic pressure estimation calculation The hydraulic pressure estimation map or the hydraulic pressure estimation calculation formula showing the correspondence between the electric motor current and rotational speed and the estimated hydraulic pressure is set in the section, and the current command value correction amount calculation section has the oil temperature and oil flow rate. And guess Table data of the oil temperature and the required motor speed corresponding to the load curve of the device in which the individual oil pressure inferred from the hydraulic pressure is added is set, the current command value correction amount calculating section estimates the hydraulic pressure from the target pressure The motor control device is characterized in that the current value is lowered when the motor speed is larger, and the motor rotational speed does not fall below the required motor rotational speed of the table data. In an electric pump unit comprising a pump that sucks and discharges oil, an electric motor for driving the pump, and a motor control device that controls the electric motor based on hydraulic pressure,
An electric pump unit, wherein the motor control device is the one described in claim 1.

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