Active control system and amplifiers including damping loops and power supplies with over-voltage protection pre-regulators

• US 6,529,073 B1
• Filed: 05/05/2000
• Issued: 03/04/2003
• Est. Priority Date: 05/06/1999
• Status: Expired due to Fees

• Current Assignee: Lord Corporation (Parker-Hannifin Corporation)
• Original Assignee: Lord Corporation (Parker-Hannifin Corporation)
• Inventors: Cranmer, Jeffrey, Ferguson, Matthew K., Highfill, John H. III
• Primary Examiner(s): NGUYEN, PATRICIA T
• Application Number:
  US09/565,726
• Time in Patent Office: 1,033 Days
• Field of Search: 330/298, 330/207.P
• US Class Current: 330/207.00P
• CPC Class Codes: H03F 1/523 for amplifiers using field-effect devices H03F1/526 takes precedence
• CPC Class Codes: H03F 3/2171 with field-effect devices H03F3/2173 - H03F3/2178 take precedence
• CPC Class Codes: H03F 3/2173 of the bridge type

Abstract

Over-voltage protection circuits are provided for power supplies that may limit input voltage spikes to a power converter and amplifiers including a damping loop that may damp filter resonance. Active damping systems incorporating the over-voltage protection circuits and/or damping loops of the present invention are also provided which may be particularly advantageous in applications such as aircraft or other vehicle applications where size and power consumption are important design considerations. The over-voltage protection circuit in various embodiments senses AC and/or DC voltage levels above a detection threshold level and momentarily disconnects the voltage input to thereby reduce the maximum voltage level input transients seen by the power converter. A capacitor may be provided to maintain the input voltage to the power converter while the input is switched out. The amplifier circuit damping loop in various embodiments is nested with a control circuit current feedback loop which may compensate for feedback problems such as instability which may result when an inductor-capacitor-inductor (L-C-L) filter is included on the output of the amplifier.

Claims

1. A power supply comprising:

a voltage source input;

a power converter coupled to the voltage source input, said power converter produces a converted voltage source signal;

a switch coupled between the voltage source input and the power converter;

a controller coupled to the voltage source input and the switch that opens the switch responsive to detection of a voltage on the voltage source input that exceeds a prescribed limit and that closes the switch responsive to detection of a voltage on the voltage source input that does not exceed the prescribed limit to limit over-voltage transients seen by the power converter;

an input voltage sense circuit having a voltage sense input coupled to the voltage source input, the input voltage sense circuit outputs an input voltage signal to the controller;

a first voltage sense circuit having a first voltage sense input coupled to the power converter, the first voltage sense circuit outputs a converted voltage signal to the controller; and

wherein the controller comprises;

a first threshold comparator coupled to the input voltage signal;

a second threshold comparator coupled to the converted voltage signal; and

a switch drive circuit that opens and closes the switch responsive to the first and second threshold comparators.

2. The power supply of claim 1 wherein the controller is further configured to generate a switch drive command signal coupled to the switch that opens the switch responsive to detection of a voltage on the voltage source input that exceeds a prescribed limit and closes the switch responsive to detection of a voltage on the voltage source input that does not exceed the prescribed limit to limit over-voltage transients seen by the power converter.

3. The power supply of claim 2 wherein the power converter is a DC to DC converter.

4. The power supply of claim 2 wherein the voltage source input comprises a DC rail.

5. The power supply of claim 2 further comprising a capacitor coupled between a high side and a low side of the voltage source input.

6. The power supply of claim 2 wherein the voltage source input comprises an AC input, the power supply further comprising:

an AC to DC converter coupled between the AC input and the switch; and

wherein the switch is coupled to the power converter by a DC rail.

7. The power supply of claim 6 wherein the controller is further configured to open the switch responsive to detection of a voltage on the DC rail that exceeds a second prescribed limit to limit over-voltage transients seen by the power converter.

8. The power supply of claim 7 wherein the power converter is a DC to DC power converter and further comprising a capacitor coupled to the DC rail.

9. The power supply of claim 1 wherein the further comprising a voltage reference signal coupled to a reference input of the second threshold comparator and wherein the switch drive circuit opens the switch responsive to the second threshold comparator when the converted voltage signal exceeds the voltage reference signal.

10. The power supply of claim 9 wherein the first and second threshold comparators are hysteretic comparators.

11. The control system of claim 1 wherein the voltage source input comprises an AC input, the system further comprising:

an AC to DC converter coupled between the AC input and the switch;

wherein the switch is coupled to the power converter by a DC rail; and

wherein the controller is further configured to open the switch responsive to detection of a voltage on the DC rail that exceeds a second prescribed limit to limit over-voltage transients seen by the power converter.