Method to reduce electromagnetic interference in switching circuit applications

Patent metadata

Field	Value
Publication number	US-10243500-B2
Application number	US-201615567584-A
Country	US
Kind code	B2
Filing date	Apr 20, 2016
Priority date	Apr 20, 2015
Publication date	Mar 26, 2019
Grant date	Mar 26, 2019

Abstract

A method for providing electromagnetic compatibility to a motor control circuit is provided. A base pulse width modulated signal is selected to apply to a motor control circuit, and comprises a duty cycle for controlling an affiliated motor. Sensed system conditions are inputted for selecting a hopping frequency and a hopping amplitude of an electro magnetic compatibility management signal. The hopping frequency and the hopping amplitude are overlayed on to the base pulse width modulated signal to create a control pulse width modulated signal. The hopping frequency dithers the frequency of the control pulse width modulated signal. The hopping amplitude restricts the amplitude of the frequency dither.

First claim

We claim:

1. A method for providing electromagnetic compatibility to a motor control circuit, comprising:
selecting a base pulse width modulated signal (BPWM) to apply to a motor control circuit, the base pulse width modulated signal comprising a duty cycle for controlling a motor affiliated with the motor control circuit;
inputting sensed system conditions;
selecting a hopping frequency and a hopping amplitude of an electro magnetic compatibility management signal based on the sensed system conditions; and
overlaying the hopping frequency and the hopping amplitude on to the base pulse width modulated signal to create a control pulse width modulated signal (CPWMS),
wherein the hopping frequency dithers the frequency of the control pulse width modulated signal, and
wherein the hopping amplitude restricts the amplitude of the frequency dither.

2. The method of claim 1 , wherein dithering the frequency of the control pulse width modulated signal comprises ramping the frequency of the motor control circuit operation in a triangular fashion over time.

3. The method of claim 1 , comprising restricting the frequency dither to +/−10% of the base pulse width modulated signal frequency.

4. The method of claim 1 , comprising restricting the frequency dither to +/−5% of the base pulse width modulated signal frequency.

5. The method of claim 1 , wherein inputted sensed system conditions comprise one or more of a clutch current hysteresis and a clutch position hysteresis.

6. The method of claim 1 , wherein inputted sensed system conditions comprise a DC BUS current of the motor control circuit.

7. The method of claim 1 , wherein inputted sensed system conditions comprise one or more of a velocity hysteresis and a current hysteresis of a pump.

8. The method of claim 1 , wherein inputted sensed system conditions comprise one or more of a clutch position, a clutch torque command, a clutch pressure, a motor speed, a motor current, and an elapsed time at the control pulse width modulated signal.

9. The method of claim 1 , wherein inputted sensed system conditions comprise one or more of a velocity of a pump, a flow rate through a pump, a fluid pressure output from the pump, a fluid pressure of a fluid input to the pump, a motor speed, a motor current, and an elapsed time at the control pulse width modulated signal.

10. A method for providing electromagnetic compatibility to a motor control circuit, comprising:
selecting a base pulse width modulated signal (BPWM) to apply to a motor control circuit, the base pulse width modulated comprising a duty cycle for controlling a motor affiliated with the motor control circuit;
inputting sensed system conditions;
selecting a hopping frequency and a hopping amplitude of an electro magnetic compatibility management signal based on the sensed system conditions; and
overlaying the hopping frequency and the hopping amplitude on to the base pulse width modulated signal to create a control pulse width modulated signal (CPWMS);
sensing the inputted sensed system conditions comprising sensing a condition at a control point; and
switching one or both of the hopping frequency and the hopping amplitude of the electro magnetic compatibility management signal in response to the sensed condition at a control point,
wherein the hopping frequency dithers the frequency of the control pulse width modulated signal, and
wherein the hopping amplitude restricts the amplitude of the frequency dither.

11. The method of claim 10 , further comprising:
sensing the inputted sensed system conditions comprising sensing a condition at a second control point; and
returning one or both of the hopping frequency and the hopping amplitude to the hopping frequency and the hopping amplitude of the electro magnetic compatibility management signal applied to the base pulse width modulated signal.

12. The method of claim 10 , wherein inputted sensed system conditions comprise one or more of a clutch current hysteresis and a clutch position hysteresis.

13. The method of claim 10 , wherein inputted sensed system conditions comprise a DC BUS current of the motor control circuit.

14. The method of claim 10 , wherein inputted sensed system conditions comprise one or more of a velocity hysteresis and a current hysteresis of a pump.

15. The method of claim 10 , wherein inputted sensed system conditions comprise one or more of a clutch position, a clutch torque command, a clutch pressure, a motor speed, a motor current, and an elapsed time at the control pulse width modulated signal.

16. The method of claim 10 , wherein inputted sensed system conditions comprise one or more of a velocity of a pump, a flow rate through a pump, a fluid pressure output from the pump, a fluid pressure of a fluid input to the pump, a motor speed, a motor current, and an elapsed time at the control pulse width modulated signal.

17. A method for providing electromagnetic compatibility to a motor control circuit, comprising:
selecting a base pulse width modulated signal (BPWM) to apply to a motor control circuit, the base pulse width modulated comprising a duty cycle for controlling a motor affiliated with the motor control circuit;
inputting sensed system conditions;
selecting a hopping frequency and a hopping amplitude of an electro magnetic compatibility management signal based on the sensed system conditions; and
overlaying the hopping frequency and the hopping amplitude on to the base pulse width modulated signal to create a control pulse width modulated signal (CPWMS);
switching the duty cycle of the base pulse width modulated signal to switch a motor operation mode from a first mode to a second mode; and
switching one or both of the hopping frequency and the hopping amplitude of the electro magnetic compatibility management signal in response to the switched duty cycle,
wherein the hopping frequency dithers the frequency of the control pulse width modulated signal, and
wherein the hopping amplitude restricts the amplitude of the frequency dither.

18. The method of claim 17 , further comprising:
sensing the inputted sensed system conditions comprising sensing a condition at a control point; and
switching one or both of the switched hopping frequency and the switched hopping amplitude of the electro magnetic compatibility management signal in response to the sensed condition at a control point.

19. A method for providing electromagnetic compatibility to a motor control circuit, comprising:
selecting a base pulse width modulated signal (BPWM) to apply to a motor control circuit, the base pulse width modulated comprising a duty cycle for controlling a motor affiliated with the motor control circuit;
inputting sensed system conditions;
selecting a hopping frequency and a hopping amplitude of an electro magnetic compatibility management signal based on the sensed system conditions; and
overlaying the hopping frequency and the hopping amplitude on to the base pulse width modulated signal to create a control pulse width modulated signal (CPWMS);
initializing a pulse width modulation counter in a pulse width modulation register;
storing the hopping frequency as a base hopping frequency in a hopping frequency register; and
storing the hopping amplitude as a base hopping amplitude in a hopping amplitude register,
wherein the hopping frequency dithers the frequency of the control pulse width modulated signal, and
wherein the hopping amplitude restricts the amplitude of the frequency dither.

20. The method of claim 19 , further c

Assignees

• Eaton Corp
• Eaton Intelligent Power Ltd

Inventors

• David James
• Suda Bharath Kumar
• Soni Asheesh

Classifications

• H02M7/53871

  with automatic control of output voltage or current · CPC title

• H04L25/4902 Primary

  Pulse width modulation; Pulse position modulation · CPC title

• H04L25/03

  Shaping networks in transmitter or receiver, e.g. adaptive shaping networks · CPC title

• H02P2207/05

  Synchronous machines, e.g. with permanent magnets or DC excitation · 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