Power factor correction using current sensing on an output

• US 20070133233A1
• Filed: 01/13/2006
• Published: 06/14/2007
• Est. Priority Date: 12/09/2005
• Status: Active Grant

• Current Assignee: Delta-Q Technologies Corp. (ZAPI S.p.A.)
• Original Assignee: Delta-Q Technologies Corp. (ZAPI S.p.A.)
• Inventors: Cameron, Robert, MacCallum, Haakon
• Granted Patent: US 7,616,455 B2
• Time in Patent Office: Days
• US Class Current: 363/16
• CPC Class Codes: G05F 1/70 Regulating power factor; Regulating reactive current or power
• CPC Class Codes: H02M 1/4258 using a single converter stage both for correction of AC input power factor and generation of a regulated and galvanically isolated DC output voltage H02M1/4241 takes precedence
• 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
• CPC Class Codes: Y02P 80/10 Efficient use of energy, e.g. using compressed air or pressurized fluid as energy carrier

Abstract

A method and apparatus for circuit conditioning, such as for providing power factor correction, is provided, using existing or minimal additional circuitry, at minimal or no additional cost to the manufacture of the circuit. The circuit conditioning is implemented by controlling an output side of the circuit based on a value sensed on the output side of the circuit and a relationship between the output side and an input side of the circuit.

Claims

1. A conditioner for an electrical circuit having an input side and an output side, said conditioner comprising:

a sensor for measuring an output electrical parameter of said output side; and

a controller connected to said sensor, said controller receiving a value indicative of said output parameter and generating a control signal to control said output parameter based on a known relationship between said output parameter and a corresponding input parameter of said input side;

wherein controlling said output parameter conditions said corresponding input parameter.

2. The conditioner of claim 1 included in a power supply wherein said input parameter is an AC signal, said output parameter is a DC signal, said input side is galvanically isolated from said output side, and controlling said output parameter provides power factor correction.

3. The conditioner of claim 1 wherein said control signal is generated with respect to a reference waveform, said reference waveform being a function of a desired waveform of said input parameter and an input-to-output transfer function of said circuit.

4. The conditioner of claim 1 further comprising a zero crossing detection circuit for indicating to said controller, when said input parameter has a value of zero.

5. The conditioner of claim 1 wherein said control signal is a pulse width modulated (PWM) signal, said control signal being varied by adjusting the duty cycle of said PWM signal.

6. The conditioner of claim 1 wherein said controller is implemented using one of an integrated circuit (IC), digital signal processor (DSP), and software.

7. The conditioner of claim 2 wherein said power supply operates in a continuous current mode.

8. The conditioner of claim 2 wherein said input and output parameters are one of electrical current and electrical voltage.

9. The conditioner of claim 2 utilizing a high frequency switching topology including one of a Clark, current-fed push-pull, and flyback topology.

10. A method for conditioning an electrical circuit having an input side and an output side, said method comprising the steps of:

sensing an output electrical parameter of said output side;

generating a control signal based on a known relationship between said output parameter and a corresponding input parameter of said input side; and

using said control signal to control said output parameter for conditioning said corresponding input parameter.

11. The method of claim 10 used in a power supply wherein said input parameter is measured from an AC signal, said output parameter is measured from a DC signal, said input side is galvanically isolated from said output side, and controlling said output parameter provides power factor correction.

12. The method of claim 10 wherein said control signal is generated with respect to a reference waveform, said reference waveform being a function of a desired waveform of said input parameter and an input-to-output transfer function of said circuit.

13. The method of claim 10 further comprising the step of detecting when said input parameter has a value of zero using a zero crossing detection circuit.

14. The method of claim 10 wherein said control signal is a pulse width modulated (PWM) signal, and further comprising the step of adjusting the duty cycle of said PWM signal when generating said control signal and using a variation of said duty cycle to control said output parameter.

15. The method of claim 11 wherein said power supply operates in a continuous current mode.