JP6079032B2 - 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 idling stop function is provided to stop the engine when the vehicle is stopped, the conventional main pump and battery are connected to secure the hydraulic pressure supply to the drive system such as the transmission even when the engine is stopped due to idling 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 an oil pressure sensor for the electric pump unit does not need to be added. 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 for an electric pump for a vehicle that controls an electric motor that drives an electric pump for the vehicle that sucks and discharges oil when the vehicle is idling stopped, the control circuit Is further provided with an overpower suppression control unit that suppresses overoutput by reducing the current command value, and the control signal output unit adds the current command value from the host controller to the current obtained by the overpower suppression control unit. The motor control signal is obtained by adding the reduction amount of the command value, and the overpower suppression control means at least determines the current and rotational speed of the electric motor. 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. The hydraulic pressure estimation unit is provided with a hydraulic pressure estimation map or a hydraulic pressure estimation calculation expression indicating a correspondence relationship between the current and rotation speed of the electric motor and the estimated hydraulic pressure. maintenance are more set in correspondence with a plurality of oil temperature zones, during idling stop, if the reduction oil temperature across the temperature zone occurs during idling stop, the motor rotation speed when straddling the oil temperature zone It is characterized by doing.

  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 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.

  If the oil temperature drop across the temperature zone occurs after idling stop, the motor rotation speed when straddling the oil temperature zone is maintained during idling stop. Thereby, generation | occurrence | production of the sound accompanying the change of a motor rotational speed is prevented.

  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 by what has been 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. Therefore, heat generation and noise due to excessive output can be suppressed to a minimum, and in particular, during idling stop, it is possible to avoid feeling uncomfortable with the sound generated by the pump accompanying the change in the rotational speed.

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 relationship between oil temperature and viscosity used in the motor control device of the electric pump unit of the present invention. FIG. 6 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 when the oil temperature is high and when the oil temperature is medium.

  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 at the time of idling 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.

  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.

  Instead of using the form of oil pressure estimation map (36), the oil pressure estimation equation using the oil temperature, power supply current (or motor current), motor rotation speed and power supply voltage is stored, and based on the oil pressure estimation equation The oil pressure can also be estimated.

  In order to secure the required output, it is necessary to improve the accuracy of hydraulic pressure estimation. FIG. 5 shows the relationship between the oil temperature and the oil viscosity. The viscosity is 100% at a temperature of 15 ° C. Thus, since the viscosity of the oil changes depending on the temperature of the oil, it is preferable to use a different hydraulic pressure estimation map or hydraulic pressure estimation calculation formula depending on the temperature.

  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 can be sent from the host ECU (19) to the electric pump unit (1), and the oil pressure estimation map (36) can be switched based on the oil temperature information. Oil temperature information should just divide 15 degreeC-110 degreeC which is a normal use range into two or more suitable zones. Here, the accuracy of the hydraulic pressure is improved by dividing the zone into many zones, but the arithmetic processing is complicated. The number of oil temperature zones is preferably set to three, that is, a low temperature zone, a medium temperature zone, and a high temperature zone in order to achieve both simplification of arithmetic processing and ensuring of accuracy of estimated hydraulic pressure.

  For example, the temperature ranges of the intermediate temperature zone and the high temperature zone are set under the condition that the amount of change in viscosity is equal. In this way, since the viscosity change is smaller at higher temperatures, the oil temperature range is wider in the high temperature zone, for example, the medium temperature zone is in the range of 20 ° C. and the high temperature zone is in the range of 30 ° C., for example. Become. In the low temperature zone, the change in viscosity accompanying the change in oil temperature is large, so it is preferable to subdivide the temperature zone in terms of viscosity estimation. However, if the viscosity is high, the oil pressure is likely to increase. Since the oil pressure can be easily obtained, there is no need to divide the temperature zone into small parts. Thus, control corresponding to the temperature can be performed with a small number of temperature zones.

  By dividing into three temperature zones, a low temperature zone, a medium temperature zone, and a high temperature zone, as shown in FIG. 6, when the temperature information is a high temperature zone (for example, 80 ° C.), control along the G graph is performed. If the temperature information is in the intermediate temperature zone (for example, 79 ° C.), control along the H graph is performed.

  Since the oil temperature is lowered by the outside air temperature, the oil temperature to be controlled in the intermediate temperature zone may be obtained while the control as the high temperature zone is being performed at the time of idling stop. In this case, when the control as the high temperature zone shifts to the control as the medium temperature zone, the motor rotation speed changes, which is recognized as an abnormal noise, and may cause discomfort. Thus, in the present embodiment, when the oil temperature drop across the temperature zone occurs after the idling stop, the motor rotation speed across the oil temperature zone is maintained during the idling stop. That is, if it is based on the temperature information, it shifts from the control along the graph of the electric pump output characteristic G for the high temperature zone to the control along the graph of the electric pump output characteristic H for the intermediate temperature zone. Control along the graph of the pump output characteristic G is continued. Thereby, generation | occurrence | production of the sound accompanying the change of a motor rotational speed is prevented.

  When the oil temperature that should be shifted to the control in the intermediate temperature zone is reached, if the control as the high temperature zone is continued, the output hydraulic pressure increases, which may increase the heat generation of the electric pump. However, the idling stop time is about 3 minutes at the maximum, and the oil temperature lowered in 3 minutes is 10 ° C. or less. The increase in oil pressure and the increase in heat generation of the electric pump when the oil temperature is lowered by 10 ° C. are negligible, and there is no disadvantage, and the generation of sound due to the change in the motor rotation speed is prevented.

  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 ) 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.

(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

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 electric power to the electric motor. In a motor control device for an electric pump for a vehicle that controls an electric motor that drives an electric pump for the vehicle that performs suction and discharge of oil based on 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. 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. The hydraulic pressure estimation map or hydraulic pressure estimation calculation formula showing the correspondence between the electric motor current and rotation speed and the estimated hydraulic pressure is set, and the hydraulic pressure estimation map or hydraulic pressure estimation calculation formula is applied to a plurality of oil temperature zones. Motor has a plurality of set up, in the idling stop, if the reduction oil temperature across the temperature zone occurs during idling stop, characterized in that to maintain the motor rotational speed when straddling the oil temperature zone Control device. In an electric pump unit including an electric pump for a vehicle that performs suction and discharge of oil, an electric motor for driving a 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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