JP6467892B2 - Motor control device - Google Patents

Description

  The present invention relates to a motor control device.

  The blower motor (hereinafter abbreviated as “motor”) control device used to blow air from a vehicle air conditioner is a rotation command signal (SI signal) received from an air conditioner ECU (Electronic Control Unit) and motor rotation detected by a hall element. The rotation of the motor is controlled based on the speed. Specifically, the motor control device controls the rotational speed of the motor using PI control that eliminates the deviation between the SI signal, which is a command value for the rotational speed, and the rotational speed of the motor detected by a Hall element or the like. .

  In order for the motor control device to perform appropriate control, it is required that the motor control device is not affected by electromagnetic noise generated from the engine or other equipment. Therefore, the motor control device is made of a material that can shield electromagnetic noise such as metal. Often covered. However, although the motor control device can be protected from electromagnetic noise by being housed in the case, electromagnetic noise may enter from the wire harness connecting the air conditioner ECU and the motor control device.

  FIG. 7 is a schematic diagram showing an example of an SI signal input to the control device, where (A) shows the case where there is no influence of electromagnetic noise, and (B) shows the case where there is an influence of electromagnetic noise. Yes. As shown in FIG. 7A, the SI signal is a pulse signal that repeats a high level signal and a low level signal, and the duty ratio is indicated by t2 / t1. However, when there is an influence of electromagnetic noise as shown in FIG. 7B, the SI signal is disturbed by the electromagnetic noise, and the high level signal is lowered. As a result, there has been a problem that the motor control device cannot normally control the rotation of the motor.

  By applying an electromagnetic shield such as a metal foil or a metal net to the wire harness, the influence of electromagnetic noise can be prevented. However, there is a problem that the manufacturing cost of the product increases due to the addition of the electromagnetic shield to the wire harness.

  Patent Document 1 discloses an invention of a motor control device that controls to stop the rotation of a motor when an SI signal is disturbed by electromagnetic noise as shown in FIG. 7B.

JP 2010-4610 A

  However, since the motor control device described in Patent Document 1 stops the motor even when there is no problem other than disturbance of the SI signal due to electromagnetic noise, there is a difficulty when it is desired to continue the rotation 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 motor control device capable of continuing the rotation of the motor when there is an influence of electromagnetic noise.

In order to solve the above problem, the motor control device according to claim 1, wherein the command signal is obtained when the high level of the command signal whose voltage level periodically changes between a high level and a low level is equal to or higher than a threshold value. The voltage applied to the motor is controlled based on the duty ratio, and when the high level falls below the threshold , at least one of the duty ratio immediately before the high level falls below the threshold and the target rotation speed The voltage applied to the motor is controlled based on the control signal, and the high level is equal to or higher than the threshold when the command signal does not periodically change and the high level is equal to or higher than the threshold for a predetermined time or longer. controlling a voltage applied to the motor based on at least one of the previous duty ratio and the target rotation speed state continues a predetermined time or more And control unit, when the high level state of less than the threshold value continues for a predetermined time or more, stops the rotation of the motor, the duty ratio immediately before the high level is continuous at or above the threshold a predetermined time or more And a stop unit for stopping the rotation of the motor when the high level continues to be equal to or higher than the threshold even after controlling the voltage applied to the motor for a predetermined time based on at least one of the target rotation speeds. Including.

  Even if the high level of the command signal becomes less than the threshold value due to the influence of electromagnetic noise or the like, this motor control device becomes less than the threshold value if the high level of the command signal is less than the threshold value within a predetermined time. The voltage applied to the motor is controlled based on the immediately preceding duty ratio. As a result, the rotation of the motor can be continued when there is an influence of electromagnetic noise.

In addition, according to this motor control device, if the input of a command signal in which a state equal to or greater than the threshold continues for a certain time or less is within a predetermined time, the duty ratio immediately before the command signal in which the state equal to or greater than the threshold continues is input. Based on this, the voltage applied to the motor is controlled. As a result, even when the command signal in which the state equal to or greater than the threshold value is an erroneous signal due to the influence of electromagnetic noise or the like, the rotation of the motor can be continued.

A motor control device according to a second aspect is the motor control device according to the first aspect, wherein the command signal is a signal input from a host control device.

According to this motor control device, even when the command signal input from the host control device is disturbed by electromagnetic noise, the rotation of the motor can be continued.

It is the schematic which shows the structure of the motor unit using the motor control apparatus which concerns on embodiment of this invention. It is a figure which shows the outline of the motor control apparatus which concerns on embodiment of this invention. It is the flowchart which showed an example of the process of the abnormal stop operation | movement of the motor control apparatus which concerns on embodiment of this invention. It is the schematic which shows the one aspect | mode of the SI signal and determination voltage in embodiment of this invention. It is the flowchart which showed an example of the process of the normal stop operation | movement of the motor by the motor control apparatus which concerns on embodiment of this invention. It is the schematic which shows an example of the motor stop signal which concerns on embodiment of this invention. It is the schematic which showed an example of SI signal input into a control apparatus, (A) has shown the case where there is no influence of electromagnetic noise, (B) shows the case where there exists the influence of electromagnetic noise, respectively.

  FIG. 1 is a schematic diagram showing a configuration of a motor unit 10 using a 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 a 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 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 the present 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, thereby blowing air in the vehicle air conditioner. It becomes possible.

  The stator 14 is attached to the motor control device 20 via the upper case 18. The motor control device 20 includes a substrate 22 of the motor control device 20 and a heat sink 24 that dissipates heat generated from elements on the substrate 22.

  A lower case 28 is attached to the motor unit 10 including the rotor 12, the stator 14, and the motor control device 20.

  FIG. 2 is a diagram schematically showing the motor control device 20 according to the present embodiment. The control circuit 50 included in the motor control device 20 is a circuit that controls the rotational speed of the motor 80 based on a command signal input from an air conditioner ECU 82 that is a host control device. In the control circuit 50, there is provided a microcomputer 30 that performs arithmetic processing related to rotation control of the motor 80.

  The control circuit 50 includes a regulator 52 for stabilizing the control voltage Vcc supplied via the diode 46, and the control voltage Vcc is applied to the microcomputer 30 via the regulator 52.

  The control circuit 50 includes a control voltage detection unit 54 that detects a voltage before being stabilized by the regulator 52, and the voltage value detected by the control voltage detection unit 54 is input to the microcomputer 30. The microcomputer 30 detects a change in the voltage (+ Vbat) of a battery (not shown) as a power source based on the voltage value input via the control voltage detection unit 54, and sends it to the inverter circuit 40 via the pre-driver 56. Adjust the output duty ratio. For example, if the battery voltage is decreasing, the duty ratio output to the inverter circuit 40 via the predriver 56 is increased, and if the battery voltage is increasing, the predriver 56 is The duty ratio output to the inverter circuit 40 is reduced.

  The control voltage Vcc stabilized by the regulator 52 is supplied to a standby circuit 58 that controls power supply to the level shifter 60. The level shifter 60 turned on by the power supply control of the standby circuit 58 adjusts the voltage of the command signal input from the air conditioner ECU 82 to generate an SI signal that is a command signal for the rotational speed of the motor 80 to generate the microcomputer 30. Output to.

  A U-phase Hall element 12U, a V-phase Hall element 12V, and a W-phase Hall element 12W that detect a magnetic field of a sensor magnet provided coaxially with the shaft 16 are connected to the microcomputer 30 via a comparator 64. The U-phase hall element 12U is a U-phase coil, the V-phase hall element 12V is a V-phase coil, and the W-phase hall element 12W is a W-phase coil. 12 positions and rotational speeds are detected. The U-phase Hall element 12U, the V-phase Hall element 12V, and the W-phase Hall element 12W output a sine wave analog signal when detecting the magnetic field of the sensor magnet that rotates with the shaft 16, but the comparator outputs the analog signal to a rectangular wave shape. It converts into a pulse signal and outputs it to the microcomputer 30.

  The thermistor 68 that detects the temperature of the circuit of the motor control device 20 is connected to the microcomputer 30 via the temperature detection unit 66. The thermistor 68 is an element whose resistance value changes according to temperature, and outputs a voltage corresponding to the change in resistance value as a signal. The temperature detector 66 calculates the temperature of the circuit based on the signal output from the thermistor 68 and outputs it to the microcomputer 30.

  The microcomputer 30 detects the position of the rotor 12 detected by the SI signal 62, the U-phase hall element 12U, the V-phase hall element 12V, and the W-phase hall element 12W, the actual rotational speed of the motor 80, and the control voltage detector 54. Based on the voltage value, the duty ratio of the voltage applied to the motor 80 is determined and output to the pre-driver 56 described above.

  Power is supplied to the pre-driver 56 via a charge pump 70 that boosts the control voltage Vcc as necessary, and a duty ratio signal output from the microcomputer 30 is used as an FET (Field Effect Transistor) is amplified to the extent that switching operation is possible. The signal output from the pre-driver 56 is detected by the voltage detector 72 and fed back to the microcomputer 30.

  The inverter circuit 40 switches electric power supplied to the U-phase, V-phase, and W-phase coils of the stator 14 of the motor 80 by the FET. The inverter circuit 40 is supplied with power from a battery as a power source via a filter 42 for noise removal. Further, the inverter circuit 40 is grounded via a reverse connection prevention FET 44 for protecting the circuit when the battery is connected positively or negatively.

  A shunt resistor 94 for detecting current is provided between the inverter circuit 40 and the reverse connection prevention FET 44. The shunt resistor 94 has a resistance value of about 0.2 mΩ to several Ω, and is connected to an amplifier 96 that amplifies the potential difference between both ends of the shunt resistor 94 and outputs a voltage value proportional to the current of the shunt resistor 94 as a signal. Has been. The amplifier 96 is provided in the control circuit 50, and a signal having a voltage value proportional to the current of the shunt resistor 94 output from the amplifier 96 is input to the microcomputer 30 in the control circuit 50.

  When the current of the inverter circuit 40 detected by the shunt resistor 94 is equal to or higher than a predetermined current threshold, or when the temperature of the circuit detected by the thermistor 68 is equal to or higher than the predetermined temperature threshold, the microcomputer 30 Control is performed to reduce the duty ratio of the applied voltage.

  The microcomputer 30 generates a signal related to the control result and outputs the signal via the signal output circuit 74. The output signal is transmitted to a host control device such as an air conditioner ECU 82, and the suitability of the operation of the motor control device 20 is determined in the host control device.

  FIG. 3 is a flowchart illustrating an example of the abnormal stop operation process of the motor control device 20 according to the present embodiment. In step 300, it is determined whether or not the SI signal input from the air conditioner ECU 82 is less than a predetermined threshold voltage.

  FIG. 4 shows one mode of the SI signal 100 and the determination voltage 102 in this embodiment. In FIG. 4, the high-level signal of the SI signal 100 exceeds the determination voltage 102 until time T1, but the SI signal 100 including the high-level signal becomes less than the determination voltage 102 due to interference of electromagnetic noise after time T1. ing. In the present embodiment, when the high level signal and the low level signal are less than the determination voltage 102 as in the SI signal 100 between the time T1 and the time T2 in FIG. In other words, although a change in the signal strength of the SI signal 100 is recognized, even if the signal strength is high (high level), an affirmative determination is made in step 300 when the determination voltage is less than 102. Alternatively, when the SI signal 100 does not change in signal strength and the state where the voltage is lower than the determination voltage 102 continues for a certain time or longer, an affirmative determination is made in step 300. The certain time is shorter than a first predetermined time described later, and is 10 milliseconds as an example.

  If the determination in step 300 is affirmative, in step 302, the rotation of the motor 80 is controlled at the target rotation speed immediately before the time T1 when the SI signal 100 changes. If the determination in step 300 is negative, the process of controlling the rotation of the motor 80 at the target rotation speed indicated by the SI signal input in step 308 is continued, and the abnormal stop operation process is terminated.

  As shown in FIG. 4, the rotation of the motor 80 was controlled at the target rotational speed 1000 rpm indicated by the SI signal 100 until time T1, but the SI signal 100 shows the determination voltage 102 between time T1 and time T2. It is below. In the present embodiment, even if the SI signal 100 falls below the determination voltage 102 from the time T1, the coil of the motor 80 has a duty ratio indicated by the SI signal input before the time T1 until a first predetermined time described later elapses. The voltage applied to is controlled. As a result, after the time T1, the rotation of the motor 80 is controlled at a target rotational speed of 1000 rpm up to the time T1.

  In the present embodiment, the target rotational speed based on the SI signal 100 output from the air conditioner ECU 82 is stored in a cache memory or the like of the microcomputer 30, and is stored when an affirmative determination is made in step 300 in FIG. The rotation of the motor 80 is controlled at the target rotational speed.

  In step 304, it is determined whether or not the state where the SI signal 100 is lower than the determination voltage 102 continues for a first predetermined time or more. The first predetermined time is, for example, 5000 milliseconds.

  If the determination in step 304 is negative, the procedure returns to step 300. In FIG. 4, the SI signal 100 is normally input from time T2. If the time T1 to the time T2 is within the predetermined time of 5000 milliseconds, a negative determination is made in step 300, and the rotation of the motor 80 is controlled at the target rotational speed 1000 rpm indicated by the SI signal 100 from the time T2.

  If the determination in step 304 is affirmative, that is, if the state where the SI signal 100 is lower than the determination voltage 102 continues for 5000 msec, which is the first predetermined time, in step 306, the target rotational speed is set to 0 rpm and the motor 80 is stopped. Let

  FIG. 5 is a flowchart illustrating an example of a normal stop operation process of the motor 80. In step 500, a motor stop signal for stopping the motor 80 is input. The motor stop signal is a command signal indicating that the duty ratio is 0. In this embodiment, the high-level signal of the determination voltage 102 or higher shown after time T1 in FIG. Signal. The fixed time is, for example, 10 milliseconds.

  In step 502, the rotation of the motor 80 is controlled at the target rotation speed immediately before the SI signal 100 changes, that is, immediately before the motor stop signal is input. In the present embodiment, the target rotational speed based on the SI signal 100 output from the air conditioner ECU 82 is stored in a cache memory or the like of the microcomputer 30, and when the motor stop signal is input in step 500 of FIG. The rotation of the motor 80 is controlled at the stored target rotation speed.

  In step 504, it is determined whether the input of the motor stop signal has continued for a second predetermined time or more. The second predetermined time in step 504 is 350 milliseconds as an example.

  If the determination in step 504 is affirmative, the target rotational speed is set to 0 rpm in step 506 and the motor 80 is stopped. If the determination in step 504 is negative, the procedure returns to step 502, and the control of the rotation of the motor 80 is continued at the target rotation speed before the motor stop signal is input.

  As described above, in the present embodiment, even if the high level signal of the SI signal becomes less than the predetermined determination voltage as a result of the disturbance of the SI signal due to the electromagnetic noise, the signal is input before being affected by the electromagnetic noise. The rotation of the motor 80 can be controlled at the target rotation speed based on the SI signal. With this control, the rotation of the motor can be continued when there is an influence of electromagnetic noise.

  Further, even when a motor stop signal indicating that the duty ratio is 0 is input, the motor 80 waits for a predetermined time and when the motor stop signal is continuously output, the rotation of the motor 80 is stopped. . When the SI signal indicating a duty ratio exceeding 0 is input before the elapse of a predetermined time after the motor stop signal is input, the previously input motor stop signal is regarded as an erroneous signal due to electromagnetic noise or the like. Even if there is some irregularity in the SI signal, the rotation of the motor can be continued.

DESCRIPTION OF SYMBOLS 10 ... Motor unit, 12 ... Rotor, 12U ... U-phase Hall element, 12V ... V-phase Hall element, 12W ... W-phase Hall element, 14 ... Stator, 16 ... Shaft, 18 ... Upper case, 20 ... Motor controller, 22 DESCRIPTION OF SYMBOLS: Board | substrate, 24 ... Heat sink, 28 ... Lower case, 30 ... Microcomputer, 40 ... Inverter circuit, 42 ... Filter, 44 ... Reverse connection prevention FET, 46 ... Diode, 50 ... Control circuit, 52 ... Regulator, 54 ... Control power supply detection 56: Pre-driver, 58 ... Standby circuit, 60 ... Level shifter, 62 ... SI signal, 64 ... Comparator, 66 ... Temperature detector, 66 ... Temperature detector, 68 ... Thermistor, 70 ... Charge pump, 72 ... Voltage detection 74: Signal output circuit, 82 ... Air conditioner ECU, 80 ... Motor, 94 ... Shunt resistance, 96 ... A Flop, 100 ... SI signal, 102 ... determination voltage, T1 ... time, T2 ... time, Vcc ... control voltage

Claims (2)

When the high level of the command signal that periodically changes between a high level and a low level is equal to or higher than a threshold value, the voltage applied to the motor is controlled based on the duty ratio of the command signal, and the high level When the voltage drops below the threshold, the voltage applied to the motor is controlled based on at least one of the duty ratio and the target rotational speed immediately before the high level falls below the threshold, and the command signal is periodically And when the state where the high level is equal to or higher than the threshold continues for a certain period of time or more, at least one of the duty ratio immediately before the state where the high level is equal to or higher than the threshold continues for a certain period of time or the target rotation speed A control unit for controlling the voltage applied to the motor based on
When the state where the high level is less than the threshold value continues for a predetermined time or longer, the rotation of the motor is stopped, and the duty ratio and the target rotation immediately before the state where the high level is equal to or higher than the threshold value continues for a predetermined time or longer. A stop unit for stopping the rotation of the motor when the high level continues to be equal to or higher than the threshold even after controlling the voltage applied to the motor based on at least one of the speeds ;
Including a motor control device. The motor control device according to claim 1, wherein the command signal is a signal input from a host control device.

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