JP6285329B2 - Blower motor control device for vehicle - Google Patents

Description

  The present invention relates to a vehicle blower motor control device.

  A semiconductor such as an FET (field effect transistor) is mounted as a switching element in an inverter circuit that controls driving of a vehicle blower motor (hereinafter abbreviated as “motor”). These semiconductors such as FETs may be damaged when the temperature exceeds a predetermined temperature.

  In order to prevent damage to semiconductors such as FETs due to heat, when the circuit is overheated, the rotation of the motor is temporarily stopped. Patent Document 1 stores a current value when a motor stop command is output, and when a start command for the motor is issued after the stop command, based on the start command and the stored current value. An invention of a motor control device that determines a target current value is disclosed.

Japanese Patent Application Laid-Open No. 2014-3802

  To control the rotational speed of the motor, the actual rotational speed approaches the target rotational speed by reducing the deviation between the target rotational speed that is the target value of the rotational speed control and the actual rotational speed that is the actual rotational speed of the motor. PI control (Proportional-Integral Controller) is used. The duty ratio of the voltage applied to the motor is calculated by PWM (Pulse Width Modulation) control. By feeding back to PWM control a correction that reduces the deviation between the target rotational speed and the actual rotational speed by PI control, A duty ratio for bringing the actual rotation speed close to the target rotation speed is calculated.

  In the PI control, P (proportional) control for correcting the deviation based on a value obtained by multiplying a deviation (P term) between the target rotational speed and the actual rotational speed by a predetermined P term gain, and accumulating the P term Then, I (integration) control for correcting the deviation with a value obtained by multiplying the I term obtained in this way by a predetermined I term gain is executed.

  In PI control, particularly in I control, the deviation between the target rotational speed and the actual rotational speed is corrected based on a continuous change in the rotational speed of the motor by PWM control. In order to temporarily stop the rotation of the motor due to overheating of the circuit as in Patent Document 1, the PWM output is interrupted and the motor output indicating the duty ratio of the voltage applied to the motor is set to 0. Since the continuity of control of the rotational speed is impaired by being interrupted, it is generally performed that the value of the I term in the PI control is also cleared to zero.

  However, since the brushless DC motor has a permanent magnet in the rotor which is a rotating body, even if the voltage applied to the motor coil is stopped to stop the motor, the rotor of the motor continues to rotate for a while due to inertia. . In such a state, when the motor output is set to 0 and the value of the I term of PI control is cleared, when the motor is restarted, the duty ratio of the voltage applied to the motor is rotating by repulsion. There is a problem that the duty ratio becomes smaller than that when the motor is rotated at the actual rotational speed, and the actual rotational speed of the motor is lower than that when the motor is rotated by repulsive force.

  FIG. 5 is a schematic diagram that compares the target rotational speed 90 of the motor, the actual rotational speed 92 of the motor, the I term, and changes in the motor output when the value of the I term is cleared when the motor is restarted in PI control. is there. If the motor rotation speed is normally controlled by the PI control as from time t0 to t1 in FIG. 5, the target rotation speed 90 and the actual rotation speed 92 substantially coincide with each other.

  At time t1 in FIG. 5, a failure occurs due to the motor or circuit temperature exceeding a predetermined threshold, and the motor drive voltage applied to the motor from the inverter circuit is cut off. As a result, the motor output becomes 0 after time t1.

  At time t2 in FIG. 5, as a result of the failure being eliminated due to a decrease in the temperature of the motor or circuit or the like, the voltage generated by the inverter circuit is applied to the motor, whereby the motor is restarted. When restarting at time t2, PI control is performed so that the target rotational speed 90 is gradually accelerated at a predetermined acceleration, and the actual rotational speed is brought close to the gradually accelerated target rotational speed in the same manner as when the motor is started. .

  However, as described above, since the PWM control is interrupted after the failure is detected, the motor output is 0 and the I term of the PI control is cleared, so the duty ratio calculated by the resumed PWM control is The duty ratio is smaller than that in the case where the motor is rotated at the actual rotation speed when it is rotated by repulsion until time t2.

As a result, the actual rotational speed of the motor decreases after restart at time t2, and as a result, an uncorrected deviation ΔR ₀ occurs between the target rotational speed 90 and the actual rotational speed 92. Although the uncorrected deviation ΔR ₀ varies depending on the motor specifications, the uncorrected deviation ΔR ₀ reached 350 to 400 rpm, which hindered smooth rotation control of the motor.

  The present invention has been made in view of the above, and an object of the present invention is to provide a vehicle blower motor control device capable of smooth rotation control when a temporarily stopped motor is restarted.

  In order to solve the above-mentioned problem, the vehicle blower motor control device according to claim 1 is a physical quantity detection unit that detects a physical quantity indicating a temperature of a motor or a circuit, a drive unit that drives the motor, and an actual rotation of the motor. When the physical quantity detected by the physical quantity detection unit is less than a threshold and no failure is detected, a proportional term and an integral term corresponding to the deviation between the target rotational speed and the actual rotational speed are used. Proportional integral control of the drive unit, and when a physical quantity detected by the physical quantity detection unit exceeds a threshold value and a failure is detected, the mode shifts to a protection operation mode in which power supply to the motor is cut off. When the physical quantity detected by the physical quantity detection unit is less than the threshold value and the protection operation mode is canceled, the actual rotational speed of the motor at the time of failure detection, Min term, and a protection operation mode includes a control unit for performing a proportional integral control based on the integral term determined using the actual rotation speed of the motor when it is released.

  This vehicle blower motor control device is determined by using the actual rotational speed of the motor at the time of failure detection, the integral term at the time of failure detection, and the actual rotational speed of the motor when the protection operation mode is canceled when the motor is restarted. Proportional integral control (PI control) is performed based on the integral term.

  Since the PI control is performed in consideration of the rotation speed of the motor rotating by inertia even when the voltage supply is cut off, the voltage drop applied to the motor when the motor is restarted is suppressed, and the temporarily stopped motor Smooth rotation control at the time of restart is possible.

  A vehicle blower motor control device according to a second aspect is the vehicle blower motor control device according to the first aspect, further comprising a storage unit for storing an integral term and an actual rotational speed when a failure is detected.

  According to this vehicle blower motor control device, the integral term and the actual rotational speed at the time of failure detection are stored. As a result, based on the stored integral term and actual rotational speed at the time of failure detection and the actual rotational speed of the motor detected by the rotational speed detection unit when the protection operation mode is canceled, the integral term at the time of failure cancellation is calculated. Can be calculated.

  The vehicle blower motor control device according to claim 3 is the vehicle blower motor control device according to claim 1 or 2, wherein the control unit detects a current actual rotational speed and a failure when the protection operation mode is canceled. Ratio with actual rotational speed at the time The drive unit is controlled based on a new integral term obtained by multiplying the integral term at the time of failure detection.

  According to this vehicle blower motor control device, when the motor is restarted, the I term that is the integral term of PI control is set to the ratio between the current actual rotational speed and the actual rotational speed at the time of failure detection. It is calculated by multiplying the I term. Since the I term is not cleared, a drop in the voltage applied to the motor when the motor is restarted is suppressed, and smooth rotation control is possible when the temporarily stopped motor is restarted.

  The vehicle blower motor control device according to claim 4 is the vehicle blower motor control device according to claim 2, wherein the controller calculates the new integral term and is proportional when the protection operation mode is canceled. The term is cleared, and the drive unit is controlled based on the product of the new integral term and a predetermined amplification coefficient.

  According to this vehicle blower motor control device, the P (proportional) term of PI control is cleared when the motor is restarted. However, a new I term calculated based on the actual rotation speed and the value of the I term stored in the storage unit when the voltage application is stopped when the current actual rotation speed and voltage application are stopped. And the drive unit is controlled based on the product of the value of I and the I term gain which is a predetermined amplification coefficient. As a result, smooth rotation control at the time of restarting the temporarily stopped motor becomes possible.

It is the schematic which shows the structure of the motor unit using the blower motor control apparatus for vehicles which concerns on embodiment of this invention. It is a figure which shows the outline of the blower motor control apparatus for vehicles which concerns on embodiment of this invention. It is the schematic which contrasted the rotational speed of the motor at the time of restart of a motor, I term, and the change of a motor output by PI control of the vehicle blower motor control apparatus which concerns on embodiment of this invention. It is a flowchart which shows an example of the motor drive control process of the blower motor control apparatus for vehicles which concerns on embodiment of this invention. It is the schematic which contrasted the change of the target rotational speed of a motor, the actual rotational speed of a motor, I term, and a motor output at the time of clearing the value of I term at the time of restart of a motor by PI control.

  FIG. 1 is a schematic diagram showing a configuration of a motor unit 10 using a vehicle blower motor control device 20 according to the present embodiment. The motor unit 10 according to the present embodiment in FIG. 1 is a so-called blower motor unit used for blowing air from an in-vehicle air conditioner as an example.

  The motor unit 10 according to the present embodiment relates to a three-phase motor having an outer rotor structure in which a rotor 12 is provided outside a stator 14. The stator 14 is an electromagnet in which a lead wire is wound around a core member, and constitutes three phases of a U phase, a V phase, and a W phase. Each of the U-phase, V-phase, and W-phase of the stator 14 generates a so-called rotating magnetic field by switching the polarity of the magnetic field generated by the electromagnet under the control of the vehicle blower motor control device 20 described later.

  A rotor magnet is provided inside the rotor 12 (not shown), and the rotor magnet rotates the rotor 12 by responding to the rotating magnetic field generated by the stator 14. The rotor 12 is provided with a shaft 16 and rotates integrally with the rotor 12. Although not shown in FIG. 1, in this embodiment, the shaft 16 is provided with a multi-blade fan such as a so-called sirocco fan, and the multi-blade fan rotates together with the shaft 16 so that air can be blown in the vehicle-mounted air conditioner. It becomes.

  The stator 14 is attached to the vehicle blower motor control device 20 via the upper case 18. The vehicle blower motor control device 20 includes a substrate 22 of the vehicle blower motor control device 20 and a heat sink 24 that dissipates heat generated from elements on the substrate 22. A lower case 60 is attached to the motor unit 10 including the rotor 12, the stator 14, and the vehicle blower motor control device 20.

  FIG. 2 is a diagram schematically illustrating the vehicle blower motor control device 20 according to the present embodiment. The inverter circuit 40 switches power supplied to the coil of the stator 14 of the motor 52. For example, the inverter FETs 44A and 44D switch the power supplied to the U-phase coil 14U, the inverter FETs 44B and 44E switch to the V-phase coil 14V, and the inverter FETs 44C and 44F switch the power supplied to the W-phase coil 14W.

  The drains of the inverter FETs 44A, 44B, and 44C are connected to the positive electrode of the on-vehicle battery 80 through a noise removing choke coil 46. The sources of the inverters FET 44D, 44E, and 44F are connected to the negative electrode of the battery 80 through the reverse connection prevention FET 48.

  In the present embodiment, the Hall element 12B detects the magnetic field of the rotor magnet 12A or the sensor magnet provided coaxially with the shaft 16. The microcomputer 32 detects the rotational speed and position (rotational position) of the rotor 12 based on the magnetic field detected by the Hall element 12B, and controls switching of the inverter circuit 40 according to the rotational speed and rotational position of the rotor 12. .

  The microcomputer 32 receives a control signal including a speed command value related to the rotational speed of the rotor 12 from the air conditioner ECU 82 that controls the air conditioner in response to the switch operation of the air conditioner. The microcomputer 32 is connected to a voltage dividing circuit 54 constituted by a thermistor 54A and a resistor 54B, and a current sensor 56 provided between the inverter circuit 40 and the negative electrode of the battery 80.

  Since the resistance value of the thermistor 54 </ b> A constituting the voltage dividing circuit 54 changes according to the temperature of the circuit board 22, the voltage of the signal output from the voltage dividing circuit 54 changes according to the temperature of the circuit board 22. The microcomputer 32 calculates the temperature of the substrate 22 based on the change in the voltage of the signal output from the voltage dividing circuit 54. In the present embodiment, for convenience, the signal output from the voltage dividing circuit 54 is a signal based on the detection result of the thermistor 54A. In the present embodiment, the temperature of the circuit board 22 calculated based on the detection result of the thermistor 54A is set as the temperature of the circuit board 22 detected by the thermistor 54A.

  The current sensor 56 includes, for example, a shunt resistor 56A and an amplifier 56B that amplifies the potential difference between both ends of the shunt resistor 56A. The microcomputer 32 calculates the current of the inverter circuit 40 based on the signal output from the amplifier 56B.

  In the present embodiment, the signal from the thermistor 54A, the signal output from the current sensor 56, and the signal output from the Hall element 12B are input to the temperature protection control unit 62 in the microcomputer 32. The temperature protection control unit 62 calculates the element temperature of the substrate 22, the current of the inverter circuit 40, the rotational speed of the rotor 12, and the like based on the input signals. The temperature protection control unit 62 is connected to a battery 80 as a power source, and the temperature protection control unit 62 detects the voltage of the battery 80 as a power supply voltage.

  A control signal from the air conditioner ECU 82 is input to the speed control unit 64 in the microcomputer 32. The speed controller 64 also receives a signal output from the Hall element 12B. The speed control unit 64 calculates the duty ratio of PWM control related to the switching control of the inverter circuit 40 based on the rotation speed and rotation position of the rotor 12 based on the control signal from the air conditioner ECU 82 and the signal from the hall element 12B. .

  A signal indicating the duty ratio calculated by the speed control unit 64 is input to the PWM output unit 66 and the temperature protection control unit 62. The temperature protection control unit 62 corrects the duty ratio calculated by the speed control unit 64 based on the temperature of the element of the substrate 22, the rotational speed of the rotor 12, and the load on the circuit of the vehicle blower motor control device 20, thereby controlling the speed. This is fed back to the unit 64. The load of the circuit is, for example, the current of the inverter circuit 40, the power supply voltage, and the duty ratio of the voltage generated by the PWM output unit 66 in the inverter circuit 40 and applied to the motor 52. In the present embodiment, as an example, the current of the inverter circuit 40, the power supply voltage, and the temperature of the substrate 22 are set as physical quantities indicating a load. In the present embodiment, the load of the motor 52 and the load of the circuit of the vehicle blower motor control device 20 are collectively referred to as a motor load.

  When the temperature of the circuit board 22 is equal to or higher than a predetermined temperature threshold, the current of the inverter circuit 40 is equal to or higher than the predetermined current threshold, and the power supply voltage is equal to or higher than the predetermined power supply voltage threshold. It is determined that a failure has been detected in the motor 52 or the circuit. When a failure is detected, a transition is made to a protection operation mode in which power supply to the motor 52 is cut off, and the temperature protection control unit 62 feeds back to the speed control unit 64 so as to stop the application of voltage to the motor 52. The speed control unit 64 stops the voltage application to the motor 52 by setting the duty ratio of the voltage applied to the motor 52 to zero. The predetermined temperature threshold, the predetermined current threshold, and the predetermined power supply voltage threshold vary depending on the specifications of the motor 52 and the vehicle blower motor control device 20, and are specifically determined through simulation using a computer, experiment using an actual machine, and the like. .

  The temperature protection control unit 62 is connected to a memory 68 that is a storage device. The memory 68 stores a program related to the processing of the I term in PI control at the time of motor restart as described later. The memory 68 also stores the rotational speed of the motor 52, the motor output by PWM control, the value of the I term, and the like.

  The speed control unit 64 feeds back the correction by the temperature protection control unit 62 to the duty ratio calculated by itself, for example, by PI control or the like, and outputs a signal indicating the duty ratio subjected to the feedback to the PWM output unit 66 as a motor output. To do. The PWM output unit 66 controls switching of the inverter circuit 40 so as to generate a voltage having a duty ratio indicated by the motor output.

  Then, the effect | action and effect of the vehicle blower motor control apparatus 20 which concern on this Embodiment are demonstrated. FIG. 3 is a schematic diagram comparing the rotational speed of the motor 52, the I term, and changes in the motor output when the motor 52 is restarted in the PI control of the vehicle blower motor control device 20 according to the present embodiment. From time t0 to time t1 in FIG. 3, the rotation speed of the motor 52 is normally controlled, and the target rotation speed 94 and the actual rotation speed 96 are substantially the same.

  At time t1 in FIG. 3, a failure occurs due to the temperature of the motor 52 or circuit exceeding a predetermined threshold value, etc., and a transition is made to a protective operation mode in which power supply to the motor 52 is cut off. The motor drive voltage is cut off. However, since the motor 52 continues to rotate while decelerating due to the inertia of the rotor 12 and the like after the time t1, in the present embodiment, the motor output is virtually calculated based on the rotation of the motor 52 detected by the Hall element 12B. The I term is calculated based on the actual rotational speed of the motor 52 that rotates by inertia without clearing the I term of PI control.

The virtual calculation of the motor output from time t1 to time t2 in FIG. 3 is performed using the following equation (1).

Further, the I term after fail detection is calculated using the following equation (2).

  For example, when the value of the I term at the time of failure occurrence (time t1) is 1000, the actual rotation speed of the motor 52 is 5000 rpm, and the actual rotation speed of the motor 52 after failure detection (from time t1 to time t2) is 4000 rpm, When the above equation (2) is used, the I term after fail detection is 800.

  At time t2 in FIG. 3, as a result of the failure being eliminated due to the temperature of the motor 52 or the circuit being lowered, the protective operation mode is canceled, and the voltage generated by the inverter circuit 40 is applied to the motor 52. Is restarted. When restarting at time t2, PI control is performed so that the target rotational speed 90 is gradually accelerated at a predetermined acceleration, and the actual rotational speed is brought close to the gradually accelerated target rotational speed in the same manner as when the motor is started. .

In the present embodiment, since the I term from the time of failure detection (time t1) is calculated by the above equation (2), the decrease in motor output after restart is suppressed more than in the case of FIG. as a result, uncorrected deviation △ R ₁ which is a deviation between the target rotational speed 94 and the actual rotational speed 96 is reduced than the case of FIG. Although the uncorrected deviation ΔR ₁ varies depending on the motor specifications, it is approximately 50 to 100 rpm, which enables smooth rotation control of the motor 52 as compared with the case of FIG.

  FIG. 4 is a flowchart showing an example of the motor drive control process of the vehicle blower motor control device 20 according to the present embodiment. In step 400, calculation of the target rotation speed, calculation of the actual rotation speed, and acquisition of the temperature of the substrate 22 detected by the thermistor 54A are started. The target rotation speed 94 is a rotation speed based on a command value input from the air conditioner ECU 82, and the actual rotation speed 96 is calculated based on a signal output from the hall element 12B.

  In step 402, it is determined whether or not a failure has been detected, for example, when the temperature of the substrate 22 detected by the thermistor 54A has become equal to or higher than a predetermined temperature threshold. If no failure is detected in step 402, the motor drive voltage is generated in the inverter circuit 40 in step 404 and applied to the motor 52.

  In step 406, the P term of PI control is calculated by subtracting the actual rotational speed from the target rotational speed. In step 408, the P term calculated in step 406 is added to the I term calculated immediately before to calculate a new I term.

  In step 410, by adding the value obtained by multiplying the new I term calculated in step 408 by the I term gain to the value obtained by multiplying the P term calculated in step 406 by the P term gain, A correction value of the motor output by PI control is calculated. In step 412, the inverter circuit 40 is controlled based on the correction value of the motor output calculated in step 410, a voltage to be applied to the motor 52 is generated, and the process is returned.

  If a failure is detected in step 402, the I term and the actual rotational speed at the time of failure detection are stored in the memory 68 in step 414, and the motor drive voltage, which is the voltage applied to the motor 52, is cut off in step 416. If the failure is resolved in step 418 because the temperature detected by the thermistor 54A is less than a predetermined temperature threshold, the value of the I term at the time of failure detection is read from the memory 68 in step 420, and step 422 is performed. The actual rotational speed 96 at the time of failure detection is read from the memory 68. If the failure has not been resolved in step 418, the procedure is shifted to step 414.

  In step 424, the P term is cleared, and in step 426, the value of the I term after fail detection is calculated using the above equation (2).

  In step 428, the value obtained by multiplying the I term calculated in step 426 by the I term gain is added to the value obtained by multiplying the P term by the P term gain, thereby correcting the motor output by PI control. Calculate the value. Since the P term is cleared in step 424, in step 426, the product of the I term and the I term gain is substantially the correction value of the motor output by PI control.

  In step 430, the inverter circuit 40 is controlled based on the correction value of the motor output calculated in step 428 to generate a voltage to be applied to the motor 52. In step 432, a process of gradually accelerating the target rotational speed at a predetermined acceleration to approach the target rotational speed based on the command value input from the air conditioner ECU 82 is started, and the procedure proceeds to step 406.

  In step 406, the P term of PI control is calculated by subtracting the actual rotational speed from the target rotational speed that is gradually increased to the target rotational speed based on the command value at a predetermined acceleration. In step 408, the P term calculated in step 406 is added to the I term calculated in step 426 to calculate a new I term.

  In step 410, by adding the value obtained by multiplying the new I term calculated in step 408 by the I term gain to the value obtained by multiplying the P term calculated in step 406 by the P term gain, A correction value of the motor output by PI control is calculated. In step 412, the inverter circuit 40 is controlled based on the correction value of the motor output calculated in step 410, a voltage to be applied to the motor 52 is generated, and the process is returned.

  As described above, according to the present embodiment, even when the energization to the motor 52 is cut off as a result of a failure detected when the temperature of the substrate 22 or the like rises above a predetermined temperature threshold value, etc. The I term of PI control is calculated based on the rotational speed of the motor 52 idling by force. As a result, when the motor 52 is restarted after the failure is eliminated, the duty ratio according to the actual rotational speed of the motor 52 idling by repulsion can be calculated, and the uncorrected deviation due to PI control can be reduced. Smooth rotation control is possible when the motor 52 is restarted.

  Further, the motor output when the failure is eliminated may be calculated using the above formula (1), and the duty ratio of the voltage applied to the motor 52 may be calculated based on the calculated motor output. Also in the equation (1), since the duty ratio is determined in consideration of the rotational speed of the motor 52 idling due to repulsion after the failure is detected, the phenomenon that the rotational speed of the motor 52 decreases when the motor 52 is restarted. Can be suppressed.

DESCRIPTION OF SYMBOLS 10 ... Motor unit, 12 ... Rotor, 12A ... Rotor magnet, 12B ... Hall element, 14 ... Stator, 14U, 14V, 14W ... Coil, 16 ... Shaft, 18 ... Upper case, 20 ... Blower motor control device for vehicles, 22 ... Substrate, 24 ... heat sink, 32 ... microcomputer, 40 ... inverter circuit, 44A, 44B, 44C, 44D, 44E, 44F ... inverter FET, 46 ... choke coil, 48 ... reverse connection prevention FET, 52 ... motor, 54 ... voltage divider circuit 54A ... Thermistor, 54B ... Resistance, 56 ... Current sensor, 56A ... Shunt resistor, 56B ... Amplifier, 60 ... Lower case, 62 ... Temperature protection control unit, 64 ... Speed control unit, 66 ... PWM output unit, 68 ... Memory 80 ... battery, 82 ... air conditioner ECU, 90 ... target rotational speed, 92 ... actual rotational speed, 94 The target rotational speed, 96 ... the actual rotational speed

Claims (4)

A physical quantity detector that detects a physical quantity indicating the temperature of the motor or circuit;
A drive unit for driving the motor;
A rotational speed detector for detecting an actual rotational speed of the motor;
When the physical quantity detected by the physical quantity detection unit is less than a threshold and no failure is detected, proportional integral control of the drive unit is performed using a proportional term and an integral term corresponding to a deviation between the target rotational speed and the actual rotational speed. At the same time, when the physical quantity detected by the physical quantity detection unit exceeds a threshold value and a failure is detected, a transition is made to a protection operation mode in which power supply to the motor is cut off, and the physical quantity detected by the physical quantity detection unit is When the protection operation mode is canceled because the threshold is less than the threshold, the actual rotation speed of the motor at the time of failure detection, the integral term at the time of failure detection, and the actual rotation speed of the motor when the protection operation mode is canceled A control unit that performs proportional-integral control based on an integral term determined using
Blower motor control device for vehicles including.   2. The vehicle blower motor control device according to claim 1, further comprising a storage unit that stores an integral term and an actual rotational speed when a failure is detected.   When the protection operation mode is canceled, the control unit adds a new integral term obtained by multiplying the ratio between the current actual rotational speed and the actual rotational speed at the time of failure detection by the integral term at the time of failure detection. The vehicle blower motor control device according to claim 1, wherein the drive unit is controlled based on the control unit.   When the protection operation mode is released, the control unit calculates the new integral term and clears the proportional term, and based on the product of the new integral term and a predetermined amplification coefficient, the driving unit The blower motor control device for a vehicle according to claim 3, wherein the blower motor is controlled.