JP2017208925A - Motor drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor drive device capable of achieving a smooth operation during a motor gear change.SOLUTION: A motor drive device 13 comprises a rotation command input part 21 for setting a target rotational speed of a motor 11 on the basis of a duty factor of a rotational speed command Si. The rotation command input part 21 sets acceleration at a speed change on the basis of a period of the input rotational speed command Si and the amount of change of the duty factor of the rotational speed command Si.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a motor driving device that controls driving of a motor.

  2. Description of the Related Art Conventionally, a motor driving device that controls driving of a motor based on a rotation command signal input from a host controller such as an ECU (Electronic Control Unit) is known (see, for example, Patent Document 1). In such a motor drive device, a rotation command signal is input as a PWM (Pulse Width Modulation) signal, and the motor is controlled according to the duty ratio of the signal.

International Publication WO2013 / 132733

  By the way, in the motor drive apparatus as described above, the target rotational speed of the motor is set based on the duty ratio of the input rotation command signal. Here, for example, when the duty ratio of the input rotation command signal is changed, the target rotational speed of the motor is changed based on the duty ratio. At this time, for example, when the target rotational speed is changed for each period of the rotation command signal and reaches the target rotational speed before the period of the rotation command signal, the speed is equal to the period for shifting (no shift) ) Period is alternately repeated, and there is a possibility that a smooth operation cannot be realized.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a motor drive device capable of realizing a smooth operation during motor shift.

  A motor driving apparatus that solves the above-described problem is a motor driving apparatus that controls driving of a motor so as to achieve a rotational speed according to a duty ratio of a rotational speed command input from the outside, and the duty ratio of the rotational speed command A speed setting unit that sets a target rotation speed of the motor based on the rotation speed command, and the speed setting unit is configured to change the speed based on a period of the input rotation speed command and a change amount of the duty ratio of the rotation speed command. Set the acceleration at.

  According to this configuration, since the acceleration at the time of changing the rotation speed of the motor is set based on the rotation speed command cycle and the amount of change in the duty ratio of the rotation speed command, the acceleration is not constant and the rotation speed command cycle It changes according to the amount of change in the duty ratio of the rotation speed command. For this reason, since the speed is continuously changed during the rotation speed command period when the speed is changed, a smooth operation can be realized.

In the motor driving device, it is preferable that the speed setting unit sets a target rotation speed of the motor based on an average value of duty ratios of the rotation speed commands for a plurality of cycles.
According to this configuration, since the target rotation speed of the motor is set based on the average value of the duty ratios of the rotation speed commands for a plurality of cycles, the duty ratio of the input rotation speed command (PWM signal) is suddenly changed. Even if it exists, since the target rotational speed is set based on the average value of a plurality of cycles, it is possible to suppress a sudden change in the rotational speed of the motor. As a result, it is possible to suppress an operation sound accompanying a sudden change in the rotation speed of the motor.

  In the motor drive device, it is preferable that the speed setting unit calculates a change amount of the duty ratio of the rotation speed command as a difference between the latest target rotation speed and the previous target rotation speed.

  According to this configuration, the amount of change in the duty ratio of the rotation speed command is calculated by calculating the difference between the latest target rotation speed set based on the duty ratio of the rotation speed command and the previous target rotation speed. Can do.

  According to the motor drive device of the present invention, it is possible to realize a smooth operation during motor speed change.

The block diagram which shows schematic structure of the motor drive system which has a motor drive device in one Embodiment. The flowchart for demonstrating the operation example of the motor drive device in the embodiment. The flowchart for demonstrating the inclination calculation process in the operation example of the motor drive device in the embodiment. The timing chart of the motor drive device in the embodiment.

Hereinafter, an embodiment of a motor drive system including a motor drive device will be described.
As shown in FIG. 1, a motor drive system 10 of this embodiment is mounted on a vehicle, and includes a motor 11 that rotates a fan to adjust the air volume of a vehicle air conditioner, and a vehicle air conditioner ECU 12. A motor driving device 13 that controls the driving of the motor 11 based on the rotation command signal Si is provided.

  In the motor 11 of this embodiment, a rotating magnetic field is formed in the stator by supplying three-phase driving currents of U phase, V phase, and W phase that are 120 degrees different from each other to the winding. This is a brushless motor in which a rotor rotates by the action of a magnet. Further, the motor 11 is provided with three position detection sensors 14 corresponding to each phase so as to detect the rotational position and rotational speed of the rotor. A detection signal Sk detected by each position detection sensor 14 is output to the motor drive device 13.

The motor drive device 13 includes a control unit 15 and a drive circuit 16.
The control unit 15 includes a rotation command input unit 21, an abnormality detection unit 22, a rotation speed input unit 23, an FB control unit 24, and a motor control unit 25.

  The rotation command input unit 21 calculates a duty ratio from the rotation command signal Si, which is an input PWM signal, determines a target rotation speed Smk as a target, and uses the target rotation speed Smk as a command value to the FB control unit 24. Output. Here, the rotation command input unit 21 of the present embodiment averages the duty ratio of the rotation command signal Si for four cycles, and determines the target rotation speed Smk from the averaged duty ratio. The detailed processing procedure in the rotation command input unit 21 will be described later.

  The abnormality detection unit 22 is for detecting an abnormality of the motor 11 or an abnormality of the motor drive device 13, and is connected to the temperature measurement unit 26, the current measurement unit 27, and the power supply voltage input unit 28. Here, the temperature measurement part 26 is comprised, for example with a thermistor, and outputs the detected temperature information to the abnormality detection part 22. The current measuring unit 27 is a shunt resistor for detecting a motor current, and outputs the detected motor current information to the abnormality detecting unit 22. The power supply voltage input unit 28 detects the voltage (power supply voltage) of a battery (not shown) mounted on the vehicle and outputs the voltage information to the abnormality detection unit 22.

  When the detection signal Sk detected by each position detection sensor 14 is input to the rotational speed input unit 23, the actual rotational speed Sjk that is the actual rotational speed of the rotor of the motor 11 calculated based on the detection signal Sk. Is output to the FB control unit 24, and the rotational position information Sik of the rotor calculated based on the detection signal Sk is output to the motor control unit 25.

  The FB control unit 24 obtains a deviation Δω between the target rotation speed Smk determined by the rotation command input unit 21 and the actual rotation speed Sjk of the rotor of the motor 11 output by the rotation speed input unit 23, and the deviation Δω Based on feedback control. The feedback control executed by the FB control unit 24 of the present embodiment is PI control. That is, the FB control unit 24 calculates the proportional component by multiplying the deviation Δω by the proportional gain Kp of P (proportional) control, and integrates the integral value of the deviation Δω by the integral gain Ki of I (integral) control. Calculate the component. The FB control unit 24 calculates the voltage command value Sv by adding the proportional component and the integral component described above, and outputs the voltage command value Sv to the motor control unit 25.

  The motor control unit 25 generates a drive signal Sd for instructing on / off based on the voltage command value Sv output from the FB control unit 24 and the rotational position information output from the rotational speed input unit 23. Output to the drive circuit 16.

  The drive circuit 16 has an inverter circuit. The inverter circuit is configured by, for example, six switching elements (for example, MOSFETs) connected in a three-phase bridge, and each switching element is turned on / off based on the driving signal Sd to supply a driving current to the winding of the motor 11. Supply.

Next, the control mode of the motor drive device 13 of this embodiment will be described.
As shown in FIG. 2, the rotation command input unit 21 first reads the rotation command signal Si (PWM signal) output from the air conditioner ECU 12 (step S10), and calculates the duty ratio of the read rotation command signal Si. (Step S11).

Next, an average value of duty ratios for four times (four cycles) of the rotation command signal Si is calculated (step S12).
The rotation command input unit 21 calculates the internal target rotation speed Smn of the motor 11 from the average value of the duty ratio for four times (four cycles) of the rotation command signal Si (step S13).

Thereafter, the rotation command input unit 21 performs an inclination calculation process (step S14).
Here, the inclination calculation processing will be described with reference to FIG. The inclination here is the amount of increase (acceleration) of the speed at the time of shifting.

  As shown in FIG. 3, the rotation command input unit 21 determines whether or not a signal for one period of the rotation command signal Si has been acquired after acquiring the latest internal target rotation speed Smn (step S30) ( Step S31).

  If the rotation command input unit 21 determines that the signal Si for one cycle has not been acquired (step S31: NO), the rotation command input unit 21 maintains the previous tilt, that is, maintains the state in which the tilt is not changed (step S31). After that, the process proceeds to step S15.

  In addition, when it is determined that the rotation command input unit 21 has acquired the signal Si for one cycle (step S31: YES), the rotation command input unit 21 reads the duty ratio of the acquired latest rotation command signal Si to obtain the previous signal Si. It is determined whether there is any change from the duty ratio (step S32).

  Then, when the duty ratio of the latest rotation command signal Si acquired has not been changed from the duty ratio of the previous signal Si (step S32: NO), the rotation command input unit 21 maintains the previous tilt, that is, changes the tilt. A state in which no operation is performed is maintained (step S33), and then the process proceeds to step S15.

  Further, when the duty ratio of the latest rotation command signal Si acquired is changed from the duty ratio of the previous signal Si (step S32: YES), the rotation command input unit 21 calculates the current target rotation speed Smn and the previous time. A difference D1 in speed from the internal target rotational speed (hereinafter referred to as the previous target rotational speed Smn1 for convenience of explanation) is calculated (step S34).

Next, the rotation command input unit 21 calculates the inclination by dividing the calculated speed difference D1 by the period of the rotation command signal Si (step S35).
Then, the rotation command input unit 21 determines whether or not the calculated inclination is larger than a limit inclination based on the characteristics of the motor 11 (step S36).

  Here, when the calculated inclination is larger than the limit inclination based on the characteristics of the motor 11 (step S36: YES), the rotation command input unit 21 sets the limit inclination as the inclination used this time (step S37), and thereafter The process proceeds to step S15.

  On the other hand, when the calculated inclination is equal to or less than the limit inclination based on the characteristics of the motor 11 (step S37: NO), the rotation command input unit 21 sets the calculated inclination as the inclination to be used this time (step S38), and then the step The process proceeds to S15.

After the inclination calculation process (step S14), the rotation command input unit 21 determines whether or not the latest target rotation speed Smn is larger than the previous target rotation speed Smn1 (step S15).
When the latest target rotational speed Smn is larger than the previous target rotational speed Smn1 (step S15: YES), the rotation command input unit 21 finally determines that the speed is to be increased with the inclination set in the inclination calculation processing. A target rotation speed Smk is set (step S17).

  When the latest target rotational speed Smn is equal to or lower than the previous target rotational speed Smn1 (step S15: NO), the rotation command input unit 21 determines whether the latest target rotational speed Smn is less than the previous target rotational speed Smn1. Determination is made (step S16).

  When the latest target rotational speed Smn is less than the previous target rotational speed Smn1 (step S16: YES), the rotation command input unit 21 determines that the speed is a final target so as to decelerate at the inclination set in the inclination calculation processing. A rotation speed Smk is set (step S18).

  In addition, when the latest target rotational speed Smn is not less than the previous target rotational speed Smn1 (step S16: NO), the rotation command input unit 21 determines that there is no change in the speed so that the final target rotational speed Smk is maintained. Is set (step S19).

  Then, the rotation command input unit 21 outputs the final target rotation speed Smk set in Steps 17, 18, and 19 to the FB control unit 24 as a command signal (Step S20).

  The FB control unit 24 determines the voltage command value Sv so that the actual rotation speed Sjk output from the rotation speed input unit 23 becomes the target rotation speed Smk set by the rotation command input unit 21, and the voltage command value Sv. Is output to the motor control unit 25.

  The motor control unit 25 generates a drive signal Sd for instructing on / off based on the voltage command value Sv and the rotation position information Sik output from the rotation speed input unit 23 and outputs the drive signal Sd to the drive circuit 16. To do.

  The drive circuit 16 supplies drive current to the windings of the motor 11 by turning on / off each switching element of the inverter circuit based on the drive signal Sd. As a result, the motor 11 is driven.

Next, the operation of the motor drive device 13 will be described.
When the rotation command signal Si is input from the air conditioner ECU 12, the rotation command input unit 21 of the motor drive device 13 calculates the internal target rotation speed Smn from the average value of the duty ratio for four cycles of the rotation command signal Si. The inclination (acceleration) is calculated based on the difference D1 between the internal target rotation speed Smn and the previous internal target rotation speed Smn1 and the period (T) of the rotation command signal Si.

  Here, as shown in FIG. 4, when the duty ratio of the rotation command signal Si is changed from X% to Y%, the average value of the duty ratio for four times is from X% to X1%, X2%, and X3%. , Y% gradually change (increase in FIG. 4). At this time, if the final target rotational speed Smk at the end of X1% is SX1, and the final target rotational speed Smk at the end of X% is SX, the difference D1 is SX1-SX, and the slope (acceleration) between them is (SX1 -SX) / T. Similarly, if the final target rotational speed Smk at the end of X2% is SX2 and the final target rotational speed Smk at the end of X1% is SX1, the difference D1 is SX2-SX1, and the inclination (acceleration) between them is (SX2- SX2) / T. Similarly, if the final target rotational speed Smk at the end of X3% is SX3 and the final target rotational speed Smk at the end of X2% is SX2, the difference D1 is SX3-SX2, and the inclination (acceleration) between them is (SX3- SX2) / T. Similarly, if the final target rotational speed Smk at the end of Y% is SX4 and the final target rotational speed Smk at the end of X3% is SX3, the difference D1 is SX4-SX3, and the slope (acceleration) between them is (SX4- SX3) / T.

As described above, by appropriately setting the acceleration in each period, the rotation of the motor 11 can be smoothly changed at the time of shifting.
Next, the effect of this embodiment will be described.

  (1) Since the acceleration at the time of changing the rotation speed of the motor 11 is set based on the cycle of the rotation command signal Si and the amount of change in the duty ratio of the rotation command signal Si, the acceleration is not constant and the cycle and rotation of the rotation command signal Si. It changes according to the change amount of the duty ratio of the command signal Si. For this reason, since the speed is continuously changed during the period of the rotation command signal Si when the speed is changed, the time for the constant speed can be reduced and a smooth operation can be realized.

  (2) Since the target rotational speed Smk of the motor 11 is set based on the average value of the duty ratio of the rotation command signal Si for four cycles, the duty ratio of the input rotation command signal Si (PWM signal) changes suddenly. Even so, since the target rotational speed Smk is set based on the average value of a plurality of cycles, it is possible to suppress a sudden change in the rotational speed of the motor 11. As a result, it is possible to suppress an operation sound accompanying a sudden change in the rotation speed of the motor 11.

  (3) The amount of change in the duty ratio of the rotation command signal Si can be calculated by calculating the difference between the latest target rotation speed set based on the duty ratio of the rotation command signal Si and the previous target rotation speed. it can.

In addition, you may change the said embodiment as follows.
In the above embodiment, the internal target rotation speed Smn is calculated using the average value of the duty ratios for four rotations of the rotation command signal Si (for four cycles), but the present invention is not limited to this. For example, the internal target rotation speed Smn may be calculated using one rotation command signal (one cycle) instead of the average value. Alternatively, an average value may be calculated from the duty ratios for two times, three times, five times or more, and the internal target rotation speed Smn may be calculated using the average value.

  In the above embodiment, the driving of the motor 11 by the motor driving device 13 is controlled based on the rotation command signal Si of the air conditioner ECU 12 mounted on the vehicle. However, the driving of the motor is performed based on the command signals of other ECUs. The motor driving device as described above may be employed in the configuration for controlling the motor. In addition to the motor mounted on the vehicle, the motor driving device as described above may be employed in a configuration for controlling the driving of a motor mounted on a device other than the vehicle.

  In the above embodiment, the FB control unit 24 performs PI control. However, P control or PID control may be used. Moreover, you may employ | adopt the structure which does not perform feedback controls, such as PI control.

Further, the rotation speed input unit 23 and each position detection sensor 14 may be omitted, and so-called sensorless control may be employed.
-You may combine the said embodiment and each modification suitably.

  DESCRIPTION OF SYMBOLS 11 ... Motor, 13 ... Motor drive device, 21 ... Rotation command input part (speed setting part), Si ... Rotation command signal (rotation speed command).

Claims (3)

A motor driving device that controls driving of a motor so as to have a rotation speed according to a duty ratio of a rotation speed command input from the outside,
A speed setting unit that sets a target rotation speed of the motor based on a duty ratio of the rotation speed command;
The speed setting unit sets an acceleration at the time of speed change based on a period of the input rotation speed command and a change amount of a duty ratio of the rotation speed command. The motor drive device according to claim 1,
The speed setting unit sets a target rotational speed of the motor based on an average value of duty ratios of the rotational speed commands for a plurality of cycles. In the motor drive device according to claim 1 or 2,
The speed setting unit calculates a change amount of a duty ratio of the rotation speed command as a difference between a latest target rotation speed and a previous target rotation speed.

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