JP2014051918A - Control device for electric pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology for removing debris engaged into an electric pump.SOLUTION: A cooling controller 39 disclosed in the present invention includes: a booster circuit 39d for increasing a drive voltage for an electric pump 32; and a motor control part 39a for boosting the drive voltage of the electric pump 32 by a booster circuit 39d when a rotation stop of the electric pump 32 is detected during supplying the drive voltage to the electric pump 32. In a case that debris is engaged into the electric pump 32 to cause the motor to be locked to stop rotation of the electric pump 32, after PWW control for decreasing an output current of an inverter circuit 39b is carried out, the drive voltage of the motor for the electric pump 32 is boosted by the booster circuit 39d, so that a higher drive voltage than the drive voltage supplied normally is supplied to the motor for the electric pump 32. The debris is removed under a state in which a current of a switching element of the inverter circuit 39b supplying the drive voltage to the motor for the electric pump 32 is not increased and the electric pump 32 is kept at a high torque state.

Description

  The technology disclosed in the present specification relates to a control device for an electric pump that pumps coolant.

  As a control device for an electric pump that pumps the coolant, there is one disclosed in Patent Document 1, for example. In this technique, when it is determined that the pump is biting foreign matter, a restart process is executed to crush or remove the bitten foreign matter.

JP 2006-258076 A

  By the way, if the motor of the electric pump is stopped while the foreign matter is caught, a larger amount of current continues to flow than usual. In the present specification, for the sake of simplicity, it is expressed as “locking” that the motor stops rotating even though the drive voltage (drive power) is supplied to the motor. The normal electric pump control device does not assume that the drive voltage is continuously supplied in a state where the motor is locked. Therefore, there is a possibility that the temperature of the circuit component that drives the electric pump rises and the circuit component is deteriorated. . The present specification provides a technique for removing foreign matters without causing deterioration of circuit components that drive an electric pump.

  The control device for the electric pump disclosed in this specification includes a booster circuit that boosts the drive voltage of the electric pump, and a booster circuit that detects a rotation stop of the electric pump while supplying the drive voltage to the electric pump. And a controller that boosts the drive voltage of the electric pump. When the motor is not locked, the pump drive circuit of the control device can drive the electric pump without a booster circuit. When the electric pump stops when the electric pump is caught by a foreign object and is locked, the drive voltage of the electric pump is boosted by the booster circuit. Without increasing the load, a drive voltage higher than the drive voltage supplied at normal time is supplied. For this reason, the electric pump is put into a high torque state to remove foreign substances without increasing the current of the semiconductor element of the pump driving circuit that supplies the driving voltage to the electric pump, thereby suppressing deterioration of circuit components that drive the electric pump. To do.

  Details of the technology disclosed in this specification and further improvements will be described in the embodiments of the present invention.

It is a block diagram of the drive system of a hybrid vehicle. It is a block diagram of the cooling system of a hybrid vehicle. It is a block diagram of a cooling controller. It is a flowchart of the pressure | voltage rise control process which the motor control part of a cooling controller performs.

  An electric pump control apparatus according to an embodiment will be described with reference to the drawings. In this embodiment, a control device for an electric pump is applied to a cooling system for cooling an inverter of a hybrid vehicle. First, the outline of this cooling system will be described with reference to FIGS. 1 and 2. FIG. 1 is a block diagram of a hybrid vehicle drive system, and FIG. 2 is a block diagram of a cooling system.

  The hybrid vehicle includes a first motor 2, a second motor 3, and an engine 4 as drive sources. The first motor 2 functions as a cell motor or a generator of the engine 4, and the second motor 3 drives a wheel in the same manner as the engine 4 as a traveling motor. The first motor 2 generates power using the torque of the engine 4 or the second motor 3 during steady running. During braking, the second motor 3 functions as a generator. The power distribution mechanism 5 synthesizes / distributes outputs from the first motor 2, the second motor 3, and the engine 4 and outputs them to the axle 6. The drive train 7 includes a first motor 2, a second motor 3, and a power distribution mechanism 5. Driving power is supplied to the first motor 2 and the second motor 3 from the main battery 11 via the voltage converter 15 and the inverters 17 and 18. Hereinafter, the first motor 2 and the second motor 3 are simply referred to as “motors 2 and 3”.

  The output voltage of the main battery 11 is 100 volts or more, and after being boosted by the voltage converter 15, it is converted into AC power by the inverters 17 and 18 and supplied to the motors 2 and 3. A system main relay 13 is interposed between the main battery 11 and the voltage converter 15. The voltage converter 15 increases the voltage of the main battery 11 to a voltage suitable for driving the motors 2 and 3, and reduces the regenerative power generated by the motors 2 and 3 to a voltage suitable for charging the main battery 11. Have The voltage converter 15 and the inverters 17 and 18 have switching elements such as IGBTs, and these are controlled by a PWM signal output from the power controller 21. The HV controller 22 calculates a running torque to be output by the drive system based on the vehicle speed, the accelerator opening, the remaining amount of the main battery 11, and outputs an appropriate command to the power controller 21. Based on this command, the power controller 21 generates the previous PWM signal and outputs it to the voltage converter 15 or the like. In addition to the main battery 11, the hybrid vehicle includes a sub-battery that supplies power to an auxiliary device (a device driven by low power, such as a headlight or audio). The output voltage of the sub-battery is 12 to 42 volts.

  The switching elements of the voltage converter 15 and the inverters 17 and 18 controlled as described above generate a large amount of heat because they switch large power. Therefore, each of these switching elements is cooled by the inverter cooler 36. The cooling system 30 circulates the coolant through the cooling pipe 31 that goes around the radiator 35, the inverter cooler 36, the reserve tank 37, and the oil cooler 38, and the switching elements of the voltage converter 15 and the inverters 17 and 18, and the oil cooler 38. Cooling. The cooling liquid is, for example, LLC (Long Life Coolant), and is pumped by the electric pump 32 and circulates in the cooling pipe 31. The oil cooler 38 is a cooling device that cools the drive train 7 with oil that circulates in the cooling pipe 52 by pumping the pump 51, and cools the motors 2 and 3 and the power distribution mechanism 5.

  The electric pump 32 has a function of rotating the internal impeller (impeller) by a brushless DC three-phase motor (hereinafter simply referred to as “motor”) and sending out the coolant in the pump by its centrifugal force. The rotation control of the motor is performed by PWM control by the cooling controller 39. In the embodiment, a rotation speed sensor 41 that detects the rotation speed of the electric pump 32, a temperature sensor 42 that detects the temperature of the coolant flowing through the cooling pipe 31, and a current sensor that detects a drive current supplied to the electric pump 32. Based on each sensor information sent from 39e, the cooling controller 39 performs PWM control of motor rotation. A block diagram of the cooling controller 39 is shown in FIG. 3, and will be described with reference to FIG.

  As shown in FIG. 3, the cooling controller 39 includes a motor control unit 39a, an inverter circuit 39b, a switching circuit 39c, a booster circuit 39d, and a current sensor 39e. Driving power is supplied to the cooling controller 39 from the sub-battery. This drive power is supplied to the inverter circuit 39b and the booster circuit 39d in addition to the motor control unit 39a including the CPU and the semiconductor memory, and rotates the motor of the electric pump 32. The inverter circuit 39b is a circuit that generates AC power that can drive a three-phase motor by performing on / off control of switching elements such as IGBTs connected in series corresponding to respective phases of the U phase, the V phase, and the W phase. Thus, these switching elements are ON / OFF controlled by the PWM control signal input from the motor control unit 39a. Normally, the output of the inverter circuit 39b can output a voltage and current sufficient to drive the electric pump 32, and is therefore directly connected to the electric pump 32. However, in the cooling controller 39 of the embodiment, the output of the inverter circuit 39b is selectively connected to either the electric pump 32 or the booster circuit 39d via the switching circuit 39c. The motor control unit 39 a controls the motor rotation of the electric pump 32 according to the temperature of the coolant measured by the temperature sensor 42. For example, the inverter circuit 39b that rotates the motor of the electric pump 32 is PWM-controlled so that the output from the electric pump 32 increases as the temperature of the coolant increases. The motor control unit 39a also performs rotation control of the electric pump 32 at a predetermined level based on the operation mode command input from the HV controller 22.

  In the embodiment, the cooling controller 39 includes a switching circuit 39c and a booster circuit 39d, which are interposed between the inverter circuit 39b and the electric pump 32. Further, the drive current output from the inverter circuit 39b is measured by the current sensor 39e and input to the motor control unit 39a. The switching circuit 39c is a semiconductor switch configured to be capable of simultaneously switching the power lines for the three phases U phase, V phase, and W phase connected from the inverter circuit 39b to the electric pump 32, and is exclusively controlled to be turned on / off. Two switch groups are provided. That is, the switching circuit 39c turns on the switch group Sb when the switch group Sa is on, or turns on the switch group Sb when the switch group Sa is off, according to the switching signal input from the motor control unit 39a. It is configured to be switchable as described above. In the embodiment, the inverter circuit 39b is connected to the electric pump 32 through the switch group Sa in the on state, and is connected to the booster circuit 39d through the switch group Sb in the on state.

  The booster circuit 39d boosts the voltage of each phase of the U-phase, V-phase, and W-phase input from the inverter circuit 39b to the same degree (for example, two times or three times), and is connected to the electric pump 32. This circuit outputs to the line. Thereby, even if a voltage lower than normal (for example, 75% of normal) is output from the inverter circuit 39b, the motor of the electric pump 32 is supplied with three-phase drive power having a voltage higher than normal. For this reason, high torque output of the impeller is possible. The booster circuit 39d, for example, charges the capacitor C by turning on the switching element in which the inductor L and the capacitor C are connected in series, and then turns back the counter electromotive force generated in the inductor L by turning off the switching element. The circuit is configured by a typical circuit that boosts in addition to the charge voltage of the capacitor C. The on / off control of the switching element may be controlled by a control signal input from the motor control unit 39a, or may be controlled by an on / off signal of a predetermined period input from the self-excited oscillation circuit. In any case, on / off control of the boost function is input from the motor control unit 39a.

  In the electric pump 32, the gap formed between the rotating impeller and the inner wall of the housing around it is very narrow. For this reason, when foreign matter such as rust and metal pieces mixed in the cooling pipe 31 is injected into the gap, the impeller is locked to prevent the motor from rotating. Sometimes. In such a case, in the embodiment, the motor control unit 39a sets the motor to a high torque output state by the boosting control process executed by the motor control unit 39a. A warning is displayed on the instool panel, or is recorded by writing to a semiconductor memory (diagnostic memory device) that records self-diagnosis information and the like. From here, the boost control processing according to the embodiment will be described with reference to FIG. FIG. 4 shows a flowchart of the boost control process executed by the motor control unit 39a.

  The step-up control process by the motor control unit 39a is repeatedly performed in the same manner as the PWM control of the electric pump 32. As a premise that this boost control process is executed, a PWM control signal for performing a normal operation at a predetermined number of revolutions is output from the motor control unit 39a to the electric pump 32.

  First, in step S111, the motor control unit 39a detects the rotational speed of the electric pump 32 by the rotational speed sensor 41. In a succeeding step S113, it is determined whether or not the electric pump 32 is locked. This determination is made based on the rotational speed of the electric pump 32. When the rotational speed of the motor detected by the rotational speed sensor 41 is zero (S113; YES), the electric pump 32 is activated even though the PWM control signal for normal operation is output from the motor control unit 39a. Since it is not rotating, there is a high probability that the electric pump 32 is locked by the above-described foreign object biting. In this case, the motor control unit 39a moves the process to step S115. On the other hand, if the rotation of the electric pump 32 is detected by the rotation speed sensor 41 (S113; NO), there is a high possibility that the rotation is normal without any foreign matter being caught, so the boost control process is temporarily terminated. (Return) and start again (Start).

  In step S115, the motor control unit 39a performs PWM control with a predetermined duty ratio. This duty ratio is set in advance and is repeatedly controlled until the current value of the output current of the inverter circuit 39b detected by the current sensor 39e in the next step S117 becomes a predetermined value. The predetermined value of this current is set to a value (small value) smaller than the output current of the inverter circuit 39b by normal PWM control. When the current value of the output current of the inverter circuit 39b is reached (S117; YES), the motor control unit 39a performs switching control of the switching circuit 39c in subsequent step S121, the switch group Sa of the switching circuit 39c is turned off, and the switch group Sb is turned on. The switching circuit 39c is switched so as to be turned on. As a result, the output of the inverter circuit 39b is input to the booster circuit 39d via the switching circuit 39c.

  In the next step S123, the motor control unit 39a performs ON control of the booster circuit 39d. Then, this on-control is maintained (S125; NO) until a predetermined time has elapsed (S125; YES). The predetermined time is, for example, 30 seconds. Thus, since the electric pump 32 continues to rotate at a high speed for the predetermined time, the foreign matter caught in the gap between the impeller and the surrounding inner wall of the housing may be ejected by the impeller rotating at a higher speed than usual. There is. When the high-speed rotation for a predetermined time is finished (S125; YES), the motor control unit 39a detects the rotation speed of the electric pump 32 again in the subsequent step S131. This detection is performed by the rotation speed sensor 41 as in step S111. And the motor control part 39a determines whether the electric pump 32 is locked based on the rotation speed of the electric pump 32 by step S133. If locked (S133; YES), the boosting circuit 39d is turned off in the subsequent step S141, and then the lock is determined in step S143. This determination is performed by counting the number of times of lock determination in step S133, and, for example, when the number exceeds three, determination is determined (S143; YES). When determined, the motor control unit 39a outputs a PWM control signal for stopping the rotation of the motor to the electric pump 32 to stop the electric pump 32. On the other hand, when the number of lock determinations in step S133 does not exceed the predetermined number from the count (S143; NO), the process returns to step S123 again to turn on the booster circuit 39d. As a result, the electric pump 32 continues to rotate at a high speed for a predetermined time, and therefore the opportunity for foreign matter to be ejected again comes.

  When the lock is released while repeating high speed rotation for a predetermined time in this manner (S133; NO), the motor control unit 39a performs the off control of the booster circuit 39d in step S151. In step S153, switching control of the switching circuit 39c is performed. In this switching control, contrary to the control in step S121, the switching circuit 39c is switched so that the switch group Sa of the switching circuit 39c is turned on and the switch group Sb is turned off. As a result, the output of the inverter circuit 39b is directly input to the electric pump 32. Thereafter, in step S155, the motor control unit 39a performs PWM control with a normal duty ratio. As a result, the electric pump 32 that has been unlocked can be subjected to normal PWM control.

  In the cooling controller 39, a booster circuit 39d that boosts the drive voltage of the electric pump 32, and when the rotation stop of the electric pump 32 is detected while the drive voltage is supplied to the electric pump 32 (S133; YES), A motor control unit 39a that boosts the drive voltage of the electric pump 32 by 39d. As a result, when foreign matter is caught in the electric pump 32 and the motor is locked and the rotation of the electric pump 32 is stopped (S133; YES), PWM control is performed to reduce the output current of the inverter circuit 39b (S115, S117; YES), since the drive voltage of the motor of the electric pump 32 is boosted by the booster circuit 39d (S123), the motor of the electric pump 32 is supplied with a drive voltage higher than the drive voltage supplied during normal operation. Is done. For this reason, since the electric pump 32 is made into a high torque output state and foreign matter is removed without increasing the current of the switching element of the inverter circuit 39b that supplies the drive voltage to the motor of the electric pump 32, a circuit for driving the electric pump 32 It is possible to suppress deterioration of components, particularly the switching element of the inverter circuit 39b.

  Points to be noted regarding the example technology will be described. The control performed by the cooling controller 39 of the embodiment is summarized as follows. The cooling controller 39 includes a drive circuit (inverter circuit 39b) that generates drive power to be supplied to the electric pump 32, a booster circuit 39d that boosts the output of the drive circuit, and the output of the drive circuit via the booster circuit. And a switching circuit 39c that selectively switches between a supply path to the power supply and a supply path that bypasses the booster circuit 39d. The cooling controller 39 supplies the output of the drive circuit to the motor while bypassing the booster circuit 39d while the electric pump 32 can rotate, and supplies the drive power to the electric pump 32 while the electric pump 32 is supplied. Is detected, it is supplied to the electric pump 32 via the booster circuit 39d. Note that “supplied to the electric pump 32 via the booster circuit 39d” more precisely means that the voltage of the output power of the drive circuit is boosted via the booster circuit 39d and supplied to the electric pump 32. is there. In addition, the cooling controller 39 switches to a path that bypasses the booster circuit 39d when the electric pump 32 starts rotating again while the drive power is being supplied to the electric pump 32 via the booster circuit.

  The cooling controller 39 corresponds to an “electric pump control device”. Further, the motor control unit 39a corresponds to an example of a “control unit”. The inverter circuit 39b corresponds to an example of a drive circuit for the pump 32, and the switching element of the inverter circuit 39b corresponds to an example of a circuit component that drives the electric pump.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. Further, the technical elements described in the present specification or drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Moreover, the technique illustrated in this specification or the drawings achieves a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

11: main battery 15: voltage converter 17, 18: inverter 21: power controller 22: HV controller 30: cooling system 31: cooling pipe 32: electric pump 35: radiator 36: inverter cooler 37: reserve tank 38: oil cooler 39: Cooling controller 39a: motor controller 39b: inverter circuit 39c: switching circuit 39d: booster circuit 39e: current sensor 41: rotation speed sensor 42: temperature sensor

Claims (1)

It is a control device for an electric pump that pumps coolant,
A booster circuit for boosting the drive voltage of the electric pump;
When detecting the rotation stop of the electric pump while supplying the drive voltage to the electric pump, a controller that boosts the drive voltage of the electric pump by a booster circuit;
An electric pump control device comprising:

Images