Power factor correction circuit

• US 6,465,990 B2
• Filed: 03/15/2001
• Issued: 10/15/2002
• Est. Priority Date: 03/15/2001
• Status: Expired due to Fees

• Current Assignee: Bensys Incorporated
• Original Assignee: Bensys Incorporated
• Inventors: Acatrinei, Beniamin, Lesea, Ronald A.
• Primary Examiner(s): Patel, Rajnikant B.
• Application Number:
  US09/810,807
• Publication Number:
  US 20020130640A1
• Time in Patent Office: 579 Days
• Field of Search: 323/222, 323/282, 323/284, 323/283, 323/285, 363/21.01, 363/127, 363/131
• US Class Current: 323/222
• CPC Class Codes: G05F 1/70 Regulating power factor; Regulating reactive current or power
• CPC Class Codes: H02M 1/4208 Arrangements for improving power factor of AC input
• 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 Parallel Charge, Series Discharge method and apparatus for power factor correction and improved efficiency comprising an energy source, two (or more) impedance(s) capable of storing and delivering electrical energy, a switching circuit having one position so that inpedance(s) charge in a parallel mode with a fraction of the electrical energy incoming from one (or more) rectified AC input generator(s), and another position so that inpedance(s) discharge some of the electrical energy stored into the load, the switch having a frequency and duty cycle so that the input current rectified waveform from the energy source will approximate the voltage rectified waveform from the energy source.

Claims

1. A power factor correction system for improving the power factor during transfer of power from an AC power source to a reactive time-varying or non-linear load comprising:

a full-wave rectifier circuit operatively connected to said AC power source for transforming an AC power signal to a DC power signal;

a reactive load;

a first impedance capable of storing energy, said first impedance coupled to said rectifier circuit so as to receive energy;

a second impedance capable of storing energy, said second impedance coupled to said first impedance and coupled to said load;

a switch coupled at one end to said first impedance and said second impedance, said switch having an open and closed state, said closed state causing said first impedance and said second impedance to store energy, said open state causing said first impedance and said second impedance to discharge energy; and

a control circuit for controlling said switch so that the input current waveform into said full-wave rectifier will approximate the voltage waveform into said full-wave rectifier input.

2. The system of claim 1 wherein said first impedance includes an inductor and said second impedance includes a capacitor.

3. A parallel charge, series discharge system for power factor correction during transfer of power from an AC power source comprising:

a full-wave rectifier circuit coupled to said AC power source;

a reactive load;

at least two impedances capable of storing electrical energy and coupled to said full-wave rectifier circuit and also coupled to said reactive load; and

a switching circuit having at least a first and second position, said first position resulting in at least two of said impedances connected in parallel for storing energy received by said full-wave rectifier, and said second position resulting in at least two of said impedances being coupled in series for discharging energy into at least one load.

4. The system of claim 3, wherein one of said impedances is an inductor and another of said impedances is a capacitor.

5. The system of claim 3 wherein said switching circuit comprises a transistor coupled to a control circuit for providing ON and OFF signals to the input terminal of said transistor, said signals corresponding to said first and second position of said switch.

6. An electronic system for improving the power factor in a circuit by means of an internal energy charge and energy discharge process comprising:

inductance means for storing and discharging electrical energy;

capacitance means for storing energy and discharging electrical energy, said capacitance means coupled to said inductance means; and

a switch connected at one end to said inductance means and said capacitance means, said switch having at least a first and second position, said first position resulting in said inductance means and said capacitance means storing electrical energy, said second position resulting in said inductance means and said capacitance means discharging electrical energy, and the frequency of said switch timing of the first and second positions such that the current waveform shape into said electronic system is approximately the same as the voltage waveform shape into said electronic system.

7. The system of claim 6 wherein said switch comprises at least one transistor and a control circuit for providing ON and OFF signals to the input terminal of said transistor, said signals corresponding to said first and second position of said switch.

8. The system of claim 7 wherein said control circuit includes a pulse generator.

9. A power factor correction system for improving the power factor and efficiency during transfer of power from an AC power source to a reactive, time-varying or non-linear load comprising:

a full-wave rectifier circuit for transforming an AC signal from said AC power source to a DC signal;

a load;

an inductive circuit capable of storing energy, said inductive circuit coupled to said full-wave rectifier;

a diode coupled at the anode to said full-wave rectifier and said inductive circuit;

a capacitive circuit capable of storing energy, said capacitive circuit coupled to the cathode of said diode, said capacitive circuit coupled to said inductive circuit and to said load;

a switch circuit coupled to said capacitive circuit and said inductive circuit at one end and coupled to circuit common at said other end, said switch having at least a first and second state, said first state causing said capacitive circuit and said inductive circuit to be in parallel with said load and said full-wave rectifier thereby allowing said capacitive circuit and said inductive circuit to store energy, said second state causing said capacitive circuit and said inductive circuit be in series with said load and said full-wave rectifier thereby causing said capacitive and said inductive circuit to discharge energy into said load; and

a control circuit comprising a pulse generator and a transistor for controlling the frequency and duty cycle of said switch states so that the input current waveform into said full-wave rectifier will approximate the voltage waveform into said rectifier input whereby the power factor is greater than 0.97 and the efficiency of the system is over 95%.

10. The system of claim 9 wherein said pulse generator is a timer 555 circuit.

11. The system of claim 9 wherein said pulse generator is a comparator oscillator circuit.

12. The system of claim 9 wherein said pulse generator is a square wave generator.

13. The system of claim 9 wherein said pulse generator is a rectangular wave generator.

14. A power factor correction system for improving the power factor during transfer of power from an AC power source to a reactive, time-varying or non-linear load comprising:

a full-wave rectifier circuit for transforming an AC signal from said AC power source to a DC signal;

a load;

an inductive circuit capable of storing energy, said inductive circuit receiving energy from said full-wave rectifier;

a capacitive circuit having a first and second terminal and capable of storing energy, said capacitive circuit coupled at said first terminal to said full-wave rectifier and said inductive circuit, said second terminal coupled and to said load;

a diode coupled at the anode to said full-wave rectifier and said inductive circuit, said diode coupled at the cathode to said load and said capacitive circuit second terminal;

a switch circuit coupled to said first terminal of said capacitive circuit and said inductive circuit, said switch having a first and second state, said first state causing said capacitive circuit and said inductive circuit to store energy and to be in parallel with said load and said full-wave rectifier, said second state causing said capacitive circuit and said inductive circuit to discharge energy and to be in series with said load and said full-wave rectifier; and

a control circuit for controlling the frequency and duty cycle of said switch states, so that the input current waveform into said full-wave rectifier will approximate the voltage waveform into said rectifier input.

15. A power factor correction system for improving the power factor and efficiency during transfer of power from an AC power source to a reactive, time-varying or non-linear load comprising:

a full-wave rectifier circuit for transforming an AC signal from said AC power source to a DC signal;

a load;

a first inductive circuit having a first and second terminal, said inductive circuit coupled at said first terminal to said full-wave rectifier and the return of said load;

a second inductive circuit having a first and second terminal, said first terminal coupled to said first inductive circuit;

a first diode coupled at the anode to said first and second said inductive circuits;

a capacitive circuit capable of storing energy and having a first and second terminal, said capacitive circuit coupled said first terminal to said first diode cathode, said capacitive circuit coupled at said second terminal to said second terminal of said second inductive circuit;

a second diode coupled at the anode to said first terminal of said capacitive circuit, said diode coupled at the cathode to said load;

a switch circuit having at least two terminals, said switch circuit coupled at said first terminal to said second terminal of said capacitive circuit and said second inductive circuit at said second terminal and coupled to circuit common at said other terminal, said switch having at least two states, said first state causing said capacitive circuit and said first and second inductive circuits to be in parallel with said load and said full-wave rectifier thereby allowing said capacitive circuit and said first and second inductive circuits to store energy, said second state causing said capacitive circuit and said inductive circuit be in series with said load and said full-wave rectifier thereby causing said capacitive and said first and second inductive circuits to discharge energy into said load; and

a control circuit comprising a pulse generator and a transistor for controlling the frequency and duty cycle of said switch states so that the input current waveform into said full-wave rectifier will approximate the voltage waveform into said rectifier input.

16. A power factor correction system for improving the power factor and efficiency during transfer of power from an AC power source to a reactive, time-varying or non-linear load comprising:

a full-wave rectifier circuit for transforming an AC signal from said AC power source to a DC signal;

a load;

a first inductive circuit having a first and second terminal, said inductive circuit coupled at said first terminal to said full-wave rectifier;

a second inductive circuit having a first and second terminal, said first terminal coupled to said second terminal of said first inductive circuit;

a capacitive circuit capable of storing energy and having a first and second terminal, said first terminal coupled to said second terminal of said first inductive circuit;

a first diode coupled having an anode and cathode, said anode coupled to said second terminal of said capacitive circuit, said cathode coupled to said load;

a second diode coupled having an anode and cathode, said anode coupled to said first terminal of said first inductive circuit, said cathode coupled to said second terminal of said capacitive circuit;

a third diode having an anode and cathode, said anode coupled to said second end of said second inductive circuit, said cathode coupled to said anode of said first diode;

a switch circuit having at least two terminals, said switch coupled to said second inductive circuit at said second terminal and coupled to circuit common at said second terminal, said switch having at least two states, said first state causing said capacitive circuit and said first and second inductive circuits to store energy, said second state causing said capacitive circuit and said first and second inductive circuits to discharge energy into said load; and

a control circuit comprising a pulse generator and a transistor for controlling said switch states so that the input current waveform into said full-wave rectifier will approximate the voltage waveform into said rectifier input.

19. A power factor correction system of claim 16 further including a second capacitor circuit having a first and second terminals, said second capacitor circuit first terminal coupled to said full-wave rectifier and said second capacitor circuit second terminal coupled to said second terminal of said second inductor, a third capacitor circuit having a first and second terminal, said third capacitor circuit first terminal coupled to said second terminal of said second inductor and said third capacitor circuit second terminal coupled to said circuit common, a fourth capacitor circuit having a first and second terminal, said fourth capacitor circuit first terminal coupled to said second terminal of said second inductor, said fourth capacitor circuit having a second terminal coupled to said load.

17. A method of parallel charge, series discharging for power factor correction in a circuit having two or more impedances and comprising:

rectifying an AC voltage wave form using a rectifier circuit coupled to an external AC power source so that a load receives a DC voltage waveform;

activating a switching circuit having at least a first and second position, said activation of switch resulting in a first position, resulting in at least two of said impedances to store energy from said full-wave rectifier circuit and said load;

storing electrical energy in at least two said impedances;

activating said switching circuit to a second position resulting in at least two of said impedances discharging energy into said load;

discharging energy stored in at least two of said impedances from said DC waveform and said load into said load; and

repeating the above steps by controlling the activation of said switch positions so that the input current waveform into said rectifier circuit will closely approximate the voltage waveform into said rectifier input.

18. The method of claim 17 wherein the activation of said switching circuit has a substantially constant duty cycle between said first and second positions whereby the power factor is greater than 0.97 and the efficiency of the system is over 95%.

20. A power factor correction system for improving the power factor and efficiency during transfer of power from an AC generator to a reactive, time-varying or non-linear load comprising:

a full-wave rectifier circuit for transforming an AC signal from the AC generator to a DC signal;

a load;

an inductive circuit having a first and second terminal, said inductive circuit first terminal coupled to said full-wave rectifier, said inductive circuit capable of storing energy from said full-wave rectifier circuit;

a capacitive circuit having a first and second terminal, said capacitive circuit first terminal coupled to said second terminal of said inductive circuit, said capacitive circuit second terminal coupled to said reactive load, said capacitive circuit capable of storing energy from said load;

a first diode having an anode coupled to said capacitive circuit first terminal, said diode having a cathode coupled to said second capacitive circuit second terminal, said diode allowing said capacitive circuit to store energy from said load;

a switch circuit having a first and second terminal, said first terminal of said switch coupled to said first terminal of said capacitive circuit and said second terminal of said inductive circuit, said second terminal of said switch coupled to circuit ground, said switch having at least two states, said first state causing said capacitive circuit to store energy from said load and said inductive circuit to store energy from said full-wave rectifier circuit, said second state causing said capacitive circuit and said inductive circuit to discharge energy into said reactive load; and

a control circuit for providing the frequency and duty cycle of said switch states so that the input current waveform into said full-wave rectifier will approximate the voltage waveform into said rectifier input.