Method to control loads using isolated drive circuits
Methods and apparatus for providing DC motor gate driver isolation. In embodiments, first and second DC input signals are received at a supply control module, which generates first and second control signals for controlling first and second switches. A first transformer has a primary winding having one end coupled to the first DC input signal and another end coupled to the first switch A second transformer has a primary winding having one end coupled to the second DC input signal and another end coupled to the second switch. The supply control module controls the first and second control signals so that a secondary winding of the first or second transformer energizes an isolated AC bus coupled to the first and second transformers. First and second gate drivers receive respective isolated AC signals from the isolated AC bus. Conversion of the isolated AC signals back to DC occurs at the point of use.
1. A method, comprising:
receiving a first DC input signal and a second DC input signal at a supply control module;
generating, by the supply control module, a first control signal for controlling a first switch, and a second control signal for controlling a second switch,
wherein a first transformer has a primary winding having one end coupled to the first DC input signal and another end coupled to the first switch, and a second transformer has a primary winding having one end coupled to the second DC input signal and another end coupled to the second switch;
controlling, by the supply control module, the first and second control signals so that a secondary winding of the first or second transformer energizes an isolated AC bus coupled to the first and second transformers;
receiving a first isolated AC signal at a first gate driver module for a motor phase, wherein the first isolated AC signal is generated by first and second coupled inductors, wherein the first coupled inductor is connected to the isolated AC bus; and
receiving a second isolated AC signal at a second gate driver module for the motor phase, wherein the second isolated AC signal is generated by third and fourth coupled inductors, wherein the third coupled inductor is connected to the isolated AC bus.
2. The method according to claim 1 , wherein the second coupled inductor is coupled to a first terminal configured for coupling to a high side drive of the motor phase.
3. The method according to claim 2 , wherein the fourth coupled inductor is coupled to a first terminal configured for coupling to a low side drive of the motor phase.
4. The method according to claim 3 , wherein the first coupled inductor is coupled to the isolated AC bus.
5. The method according to claim 4 , wherein the first gate driver module controls a first motor switch configured for coupling the positive DC input to the motor phase, and the second gate driver module controls a second motor switch configured for coupling the negative DC input to the motor phase, and wherein the second coupled inductor is coupled to a node between the first and second motor switches.
6. The method according to claim 5 , wherein an isolated AC voltage on the second coupled winding is referenced to the voltage at the motor phase connection.
7. The method according to claim 1 , wherein the supply control module comprises an IC package.
8. The method according to claim 7 , wherein the first and second gate driver modules comprise IC packages.
9. The method according to claim 1 , wherein there is no conversion back to DC of the first DC input signal and/or the second DC input signal until DC rectification in the first and second gate driver modules.
10. The method according to claim 1 , wherein the supply control module comprises an oscillator and a regulator in a feed forward regulation configuration.
11. The method according to claim 1 , wherein the supply control module automatically switches between primary operation where the first DC input signal energizes the isolated AC bus and secondary operation wherein the second DC input signal energizes the isolated AC bus.
12. The method according to claim 1 , further including rectifying, by the first and second gate driver modules, which comprises IC packages, the first isolated AC signal for generating voltage supply signals for the first and second gate driver modules.
13. The method according to claim 12 , wherein the voltage supply signals include a first voltage supply signal, a negative voltage supply signal, and a programmable voltage supply signal.
14. A system, comprising:
a supply control module configured to receive a first DC input signal and a second DC input signal and to generate a first control signal for controlling a first switch and a second control signal for controlling a second switch;
a first transformer including a primary winding having one end configured for coupling to the first DC input signal and another end coupled to the first switch, and a second transformer including a primary winding having one end configured for coupling to the second DC input signal and another end coupled to the second switch, wherein the supply control module is configured to control the first and second control signals so that a secondary winding of the first or second transformer energizes an isolated AC bus coupled to the first and second transformers;
a first gate driver module for a motor phase configured to receive a first isolated AC signal generated by first and second coupled inductors, wherein the first coupled inductor is connected to the isolated AC bus; and
a second gate driver module for the motor phase configured to receive a second isolated AC signal generated by third and fourth coupled inductors, wherein the third coupled inductor is connected to the isolated AC bus.
15. The system according to claim 14 , wherein the second coupled inductor is coupled to a first terminal configured for coupling to a high side driver of the motor phase.
16. The system according to claim 15 , wherein the fourth coupled inductor is coupled to a first terminal configured for coupling to a low side driver of the motor phase.
17. The system according to claim 16 , wherein the first coupled inductor is coupled to the isolated AC bus.
18. The system according to claim 17 , wherein the first gate driver module controls a first motor switch configured for coupling the positive DC input to the motor phase, and the second gate driver module controls a second motor switch configured for coupling the negative DC input to the motor phase, and wherein the second coupled inductor is coupled to a node between the first and second motor switches.
19. The system according to claim 18 , wherein an isolated AC voltage on the second coupled winding is referenced to the motor phase during operation of the motor.
20. The system according to claim 14 , wherein the supply control module comprises an IC package.
21. The system according to claim 20 , wherein the first and second gate driver modules comprise IC packages.
22. The system according to claim 14 , wherein the system is configured such that there is no conversion back to DC of the first DC input signal and/or the second DC input signal until DC rectification in the first and second gate driver modules.
23. The system according to claim 14 , wherein the supply control module comprises an oscillator and a regulator in a feed forward regulation configuration.
24. The system according to claim 14 , wherein the supply control module is configured to automatically switch between primary operation where the first DC input signal energizes the isolated AC bus and secondary operation wherein the second DC input signal energizes the isolated AC bus.
25. The system according to claim 14 , wherein the first and second gate driver modules, which comprise IC packages, include a rectifier for generating voltage supply signals for the first gate driver module.
26. The system according to claim 25 , wherein the voltage supply signals include a first voltage supply signal, a negative voltage supply signal, and a programmable voltage supply signal.