Motor driving device

Patent metadata

Field	Value
Publication number	US-10574169-B2
Application number	US-201716080768-A
Country	US
Kind code	B2
Filing date	Mar 2, 2017
Priority date	Mar 3, 2016
Publication date	Feb 25, 2020
Grant date	Feb 25, 2020

Abstract

API duty calculation unit of a microcomputer that performs control at a predetermined control period calculates a duty ratio of a voltage applied to a coil of a motor from a target rotation speed and an actual rotation speed calculated by a number-of-rotation information unit. The PI duty calculation unit generates a rectangular wave signal having a period according to one frequency selected from plural predetermined frequencies together with the start of one control period and indicating the calculated duty ratio, and outputs the rectangular wave signal to a PWM duty calculation unit. The PWM duty calculation unit generates a PWM signal for controlling an inverter circuit based on the rectangular wave signal output by the PI duty calculation unit and position information of a rotor of the motor calculated by an electrical angle position information unit.

First claim

The invention claimed is:

1. A motor driving device comprising:
a driving unit that includes a plurality of switching elements, each of which is on or off controlled by a pulse width modulation signal, and that drives a motor with a driving voltage according to an on or off state of the plurality of switching elements; and
a control unit (i) that repeatedly operates at a predetermined cycle, (ii) that selects at the start of operation a signal from a plurality of predetermined signals having different frequencies, (iii) that generates a pulse width modulation signal based on a command signal and the selected signal, and (iv) that controls the on or off state of the plurality of switching elements of the driving unit by using the generated pulse width modulation signal.

2. The motor driving device according to claim 1 , wherein the control unit sequentially selects one different signal from the plurality of predetermined signals and, after selecting a last one of the plurality of predetermined signals, repeats to sequentially select one different signal.

3. The motor driving device according to claim 1 , wherein the control unit randomly selects one signal from the plurality of predetermined signals.

4. The motor driving device according to claim 1 , wherein the control unit determines one of the plurality of predetermined signals as a reference signal and corrects a pulse width modulation signal generated based on a signal other than the reference signal, such that a driving voltage generated by using the pulse width modulation signal based on the signal other than the reference signal becomes equal to a driving voltage generated by using a pulse width modulation signal based on the reference signal.

5. The motor driving device according to claim 4 , wherein the control unit corrects the pulse width modulation signal based on the signal other than the reference signal, such that substantial values become equal, the substantial values being the pulse width modulation signal based on the reference signal and the pulse width modulation signal based on the signal other than the reference signal from each of which an influence of dead time is excluded.

6. The motor driving device according to claim 1 , further comprising:
a rotation speed detection unit that detects a rotation speed of the motor, and
wherein the control unit calculates a driving voltage of the motor so as to eliminate a deviation between a target rotation speed indicated by the command signal and an actual rotation speed of the motor detected by the rotation speed detection unit.

7. The motor driving device according to claim 1 , wherein the plurality of predetermined signals comprises at least three of the predetermined signals.

8. The motor driving device according to claim 1 , wherein after selecting the selected signal, the control unit selects another signal of the plurality of predetermined signals having a frequency lower than that of the selected signal.

9. A motor driving device comprising:
a driving unit that includes a plurality of switching elements, each of which is on or off controlled by a pulse width modulation signal, and that drives a motor with a driving voltage according to an on or off state of the plurality of switching elements; and
a control unit that repeatedly operates at a predetermined cycle, that generates a pulse width modulation signal based on a command signal and a signal selected from a plurality of predetermined signals having different frequencies at the start of operation, and that controls the on or off state of the plurality of switching elements of the driving unit by using the generated pulse width modulation signal,
wherein the control unit determines one of the plurality of predetermined signals as a reference signal and corrects a pulse width modulation signal generated based on a signal other than the reference signal, such that a driving voltage generated by using the pulse width modulation signal based on the signal other than the reference signal becomes equal to a driving voltage generated by using a pulse width modulation signal based on the reference signal.

10. The motor driving device according to claim 9 , wherein the control unit corrects the pulse width modulation signal based on the signal other than the reference signal, such that substantial values become equal, the substantial values being the pulse width modulation signal based on the reference signal and the pulse width modulation signal based on the signal other than the reference signal from each of which an influence of dead time is excluded.

Assignees

• Denso Corp

Inventors

• Otsuka Hikaru

Classifications

• H02P27/06

  using DC to AC converters or inverters (H02P27/05 takes precedence) · CPC title

• H02P27/045

  whereby the speed is regulated by measuring the motor speed and comparing it with a given physical value · CPC title

• B60H1/00428

  electric · CPC title

• H02P27/085 Primary

  wherein the PWM mode is adapted on the running conditions of the motor, e.g. the switching frequency · CPC title

• B60H1/00642

  Control systems or circuits; Control members or indication devices for heating, cooling or ventilating devices (B60H1/3201 - B60H1/3208, B60H1/3225 take precedence) · CPC title