Bipolar power control

• US 9,219,428 B2
• Filed: 01/26/2009
• Issued: 12/22/2015
• Est. Priority Date: 02/02/2008
• Status: Active Grant

• Current Assignee: Redisem Ltd.
• Original Assignee: Russell Jacques
• Inventors: Jacques, Russell
• Primary Examiner(s): Laxton, Gary L
• Assistant Examiner(s): LEE III, HENRY E
• Application Number:
  US12/735,594
• Publication Number:
  US 20110007525A1
• Time in Patent Office: 2,521 Days
• Field of Search: 363 17- 19
• US Class Current: 1/1
• CPC Class Codes: H02M 7/537 using semiconductor devices only, e.g. single switched pulse inverters
• CPC Class Codes: H05B 41/2827 using specially adapted components in the load circuit, e.g. feed-back transformers, piezoelectric transformers; using specially adapted load circuit configurations
• CPC Class Codes: H05B 41/2828 using control circuits for the switching elements H05B41/2827 takes precedence
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A circuit for controlling a power converter featuring BJTs, through use of a control winding on the transformer that provides the base drive for the BJTs is disclosed. This controller can control the control winding current, thus modifying the commutating of the current or stopping the oscillations. It can provide unidirectional shorts to prevent commutation and can also provide an initial power pulse to control the start or operation of the power converter.

Claims

1. A controller for controlling a power converter, the power converter having first and second bipolar junction transistors (BJTs) as switches, a first drive winding connected between a base and an emitter of the first BJT and a second drive winding connected between a base and an emitter of said second BJT, said first and second drive windings being magnetically coupled to a load winding which carries the power converter load current, the controller having a current control element comprising:

first and second control winding connections for connection to a control winding magnetically coupled to the load and drive windings;

first and second switches, said first and second switches being bidirectional electronic switches arranged in series with each other between the first and second control winding connections to provide a bidirectional short-circuit between said first and second control winding connections when said first and second switches are closed; and

a first diode connected in parallel with the first switch to provide a unidirectional short-circuit between said first and second control winding connections when only said second switch is closed.

2. The controller according to claim 1, wherein electric paths are formed between each of the first and second switches and a respective one of the control winding connections and the paths include no diode.

3. The controller according to claim 1, further comprising a control unit for controlling the first and second switches.

4. The controller according to claim 3, wherein the control unit is operable to control the first and second switches to selectively close both the first and second switch to provide a bidirectional short-circuit between the first and second control winding connections.

5. The controller according to claim 3, wherein the control unit is operable to control the first and second switches to selectively open the first switch and close the second switch to provide a unidirectional short-circuit between the first and second control winding connections via the first diode.

6. The controller according to claim 3, wherein the control unit is operable to control the first and second switches to selectively open both the first and second switches to electrically disconnect the first and second control winding connections.

7. The controller according to claim 3, wherein the current control element further comprises a third switch coupled between a first power supply connection and the first control winding connection.

8. The controller according to claim 7, wherein said control unit is operable to control said third switch to selectively provide a connection between the first power supply connection and the first control winding connection.

9. The controller according to claim 7, wherein said current control element further comprises a fourth switch coupled between said first power supply connection and said second control winding connection.

10. The controller according to claim 9, wherein said control unit is operable to control the fourth switch to selectively provide a connection between the first power supply connection and the second control winding connection.

11. The controller according to claim 10, wherein the control unit is arranged to selectively close the third or fourth switches to control the direction of the current flow in the control winding.

12. The controller according to claim 7, wherein a second power supply connection is coupled between the first switch and the second switch.

13. The controller according to claim 3, further comprising a second diode connected in parallel with the second switch and oriented in opposition to the first diode to prevent current flowing through both the first and second diodes simultaneously, and wherein the control unit is arranged to selectively close the first switch and open the second switch to provide a unidirectional short-circuit between the control winding connections via the second diode.

14. The controller according to claim 1, further comprising a second diode connected in parallel with the second switch and oriented in opposition to the first diode to prevent current flowing through both the first and second diodes simultaneously.

34. The controller according to claim 1, wherein said first and second bidirectional electronic switches are Field Effect Transistors.

35. The controller according to claim 3, wherein the control unit has one or more voltage sensing connections electrically coupled to one of said switches in the current control element to measure the current flowing through them.

36. The controller according to claim 35, wherein the control unit controls the switches based on the voltage on one or more of the voltage sensing connections.

15. A controller for controlling a power converter, the power converter having first and second bipolar junction transistors (BJTs) as switches, a first drive winding connected between a base and an emitter of the first BJT and a second drive winding connected between a base and an emitter of said second BJT, said first and second drive windings being magnetically coupled to a load winding which carries the power converter load current, the controller having a current control element comprising:

first and second control winding connections for connection to a control winding magnetically coupled to the load and drive windings; and

a first switch in the form of a Field Effect Transistor (FET) arranged between the first and second control winding connections to provide a bidirectional short-circuit between the first and second control winding connections that does not include a diode and thereby effectively providing a short circuit between the base and the emitter of the respective first and second BJTs to control oscillation of the converter.

16. The controller according to claim 15, wherein the current control element further comprises a second switch arranged between a first power supply connection and the first control winding connection.

17. A controller for controlling a power converter, the power converter having first and second bipolar junction transistors (BJTs) as switches, a first drive winding connected between a base and an emitter of the first BJT and a second drive winding connected between a base and an emitter of said second BJT, said first and second drive windings being magnetically coupled to a load winding which carries the power converter load current, the controller having a current control element comprising:

first and second control winding connections for connection to a control winding magnetically coupled to the load and drive windings;

a first switch, said first switch being a bidirectional electronic switch arranged between the first and second control winding connections to provide a bidirectional short-circuit between the first and second control winding connections when said first switch is closed; and

a second switch arranged between a first power supply connection and the first control winding connection to provide power to said control winding.

18. The controller according to claim 17, wherein electric paths are formed between the first switch and each of the first and second control winding connections and the paths include no diode.

19. The controller according to claim 17, further comprising a control unit to control the first and second switches.

20. The controller according to claim 19, wherein the control unit is operable to control the first switch to selectively close to provide a bidirectional short-circuit between the first and second control winding connections.

21. The controller according to claim 19, wherein the control unit is operable to control the second switch to selectively provide a connection between the first power supply connection and the first control winding connection.

22. The controller according to claim 19, wherein the current control element further comprises a third switch coupled between said first power supply connection and said second control winding connection.

23. The controller according to claim 22, wherein the control unit is operable to control the third switch to selectively provide a connection between the first power supply connection and the second control winding connection.

24. The controller according to claim 22, wherein the current control element further comprises:

a fourth switch, said fourth switch being a bidirectional electronic switch coupled between said first switch and said second control winding connection; and

a first diode connected in parallel with the first switch.

25. The controller according to claim 24, wherein said control unit is arranged to control said first and fourth switches to selectively open the first switch and close the fourth switch, to provide a unidirectional short-circuit between the first and second control winding connections via the first diode.

26. The controller according to claim 24, further comprising a second diode connected in parallel with the fourth switch and oriented in opposition to the first diode to prevent current flowing through both the first and second diode simultaneously.

27. The controller according to claim 26, wherein the control unit is arranged to control the first and fourth switches to selectively close the first switch and open the fourth switch, to provide a unidirectional short-circuit between the first and second control winding connections via the second diode.

28. The controller according to claim 24, further comprising a second power supply connection coupled between the first and second switch.

29. The controller according to claim 19, wherein the control unit has one or more voltage sensing connections electrically coupled to one of said switches in the current control element for measuring the current flowing through them.

30. The controller according to claim 29, wherein the control unit controls the switches based on the voltage on one or more of the voltage sensing connections.

31. A method for controlling a power converter, the power converter having first and second bipolar junction transistors (BJTs) as switches, a first drive winding connected between a base and an emitter of the first BJT and a second drive winding connected between a base and an emitter of said second BJT, said first and second drive windings being magnetically coupled to a load winding which carries the power converter load current, wherein control over the power converter is achieved by controlling a control winding magnetically coupled to said drive winding, the method comprising the step of selectively providing a bidirectional short-circuit across the control winding that does not include a diode and thereby effectively providing a short circuit between the base and the emitter of the respective first and second BJTs to control oscillation of the converter.

33. The method of claim 31, further comprising the step of selectively controlling the current in the control winding by providing additional current to the control winding to modify the current in the drive winding.

37. The method of claim 31, further comprising the step of selectively controlling the current in the control winding by providing additional current to the control winding to modify the current in the drive winding.

32. A method for controlling a power converter, the power converter having first and second bipolar junction transistors (BJTs) as switches, a first drive winding connected between a base and an emitter of the first BJT and a second drive winding connected between a base and an emitter of said second BJT, said first and second drive windings being magnetically coupled to a load winding which carries the power converter load current, wherein control over the power converter is achieved by controlling a control winding magnetically coupled to said drive winding, the method comprising the step of selectively providing one of:

a bidirectional short-circuit across the control winding and thereby effectively providing a short circuit between the base and the emitter of the respective first and second BJTs to control oscillation of the converter;

a unidirectional short-circuit across the control winding and thereby effectively providing a short circuit between the base and the emitter of one of the first and second BJTs to control oscillation of the converter; and

no electrical path across the control winding.