Power factor correction converter

• US 7,919,950 B2
• Filed: 01/05/2010
• Issued: 04/05/2011
• Est. Priority Date: 07/09/2007
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Tokugawa, Tomokuni, Uno, Yoshiyuki, Hosotani, Tatsuya
• Primary Examiner(s): Riley; Shawn
• Application Number:
  US12/652,103
• Publication Number:
  US 20100097829A1
• Time in Patent Office: 455 Days
• Field of Search: 323/207, 323/222, 363/89, 363/127
• US Class Current: 323/207
• CPC Class Codes: H02M 1/0085 Partially controlled bridges
• CPC Class Codes: H02M 1/4225 using a non-isolated boost converter
• CPC Class Codes: H02M 1/44 Circuits or arrangements for compensating for electromagnetic interference in converters or inverters
• CPC Class Codes: H02M 3/157 with digital control
• 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 power factor correction converter includes a diode bridge arranged to perform full-wave rectification on an AC input power supply, a switching element arranged to perform switching on an output voltage thereof, an inductor arranged to pass a current interrupted by the switching element and to accumulate and emit excitation energy, a diode, and a smoothing capacitor defining a step-up chopper circuit. A digital signal processing circuit detects a phase of an input voltage, and a switching frequency of the switching element is modulated in accordance with the phase. Accordingly, the switching frequency can be appropriately modulated without depending on an input voltage, so that a wide range of input voltages can be accepted while suppressing EMI noise with a peak generated in the switching frequency and higher-order frequency components thereof.

Claims

1. A power factor correction converter comprising:

at least two switching circuits arranged to perform switching on an AC voltage input from an AC input power supply;

an inductor arranged to pass a current interrupted by the at least two switching circuits;

a smoothing circuit arranged to smooth an output voltage in a stage after the inductor;

a phase detecting circuit arranged to detect a phase of a voltage of the AC input power supply; and

a switching frequency modulating circuit arranged to modulate a switching frequency of the at least two switching circuits in accordance with a phase of a voltage waveform of the AC input power supply, a half cycle of the voltage waveform of the AC input power supply defining one cycle.

3. The power factor correction converter according to claim 1, wherein, based on the phase of the voltage of the AC input power supply, the switching frequency modulating circuit decreases the switching frequency of the switching circuit when an instantaneous value of the voltage of the AC input power supply is at a lower limit or in the vicinity of the lower limit, and increases the switching frequency of the switching circuit when the instantaneous value of the voltage of the AC input power supply is at an upper limit or in the vicinity of the upper limit.

4. The power factor correction converter according to claim 1, wherein the switching frequency modulating circuit is arranged to obtain a peak value or an effective value of an input voltage based on an instantaneous value obtained through sampling of the voltage of the AC input power supply and to shift a modulation range of the switching frequency of the switching circuit to a low frequency side as the peak value or the effective value is increased.

5. The power factor correction converter according to claim 1, wherein the phase detecting circuit includes a waveform shaping circuit arranged to shape a waveform of a voltage signal of the AC input power supply to generate a substantially-rectangular-wave signal, and a circuit arranged to detect a rise and/or fall time of the rectangular-wave signal.

6. The power factor correction converter according to claim 1, wherein the phase detecting circuit is arranged to sample a voltage signal of the AC input power supply and detect at least one of a time when an instantaneous value of the voltage signal reaches a peak, a time when the instantaneous value is a minimum, and a time when the instantaneous value is a predetermined value.

2. A power factor correction converter comprising:

a rectifier circuit arranged to perform full-wave rectification on an AC input power supply;

a switching circuit arranged to perform switching on an output voltage of the rectifier circuit;

an inductor arranged to pass a current interrupted by the switching circuit;

a smoothing circuit arranged to smooth the output voltage in a stage after the inductor;

a phase detecting circuit arranged to detect a phase of a voltage of the AC input power supply; and

a switching frequency modulating circuit arranged to modulate a switching frequency of the switching circuit in accordance with a phase of a voltage waveform of the AC input power supply, a half cycle of the voltage waveform of the AC input power supply defining one cycle.

7. The power factor correction converter according to claim 2, wherein, based on the phase of the voltage of the AC input power supply, the switching frequency modulating circuit decreases the switching frequency of the switching circuit when an instantaneous value of the voltage of the AC input power supply is at a lower limit or in the vicinity of the lower limit, and increases the switching frequency of the switching circuit when the instantaneous value of the voltage of the AC input power supply is at an upper limit or in the vicinity of the upper limit.

8. The power factor correction converter according to claim 2, wherein the switching frequency modulating circuit is arranged to obtain a peak value or an effective value of an input voltage based on an instantaneous value obtained through sampling of the voltage of the AC input power supply and to shift a modulation range of the switching frequency of the switching circuit to a low frequency side as the peak value or the effective value is increased.

9. The power factor correction converter according to claim 2, wherein the phase detecting circuit includes a waveform shaping circuit arranged to shape a waveform of a voltage signal of the AC input power supply to generate a substantially-rectangular-wave signal, and a circuit arranged to detect a rise and/or fall time of the rectangular-wave signal.

10. The power factor correction converter according to claim 2, herein the phase detecting circuit is arranged to sample a voltage signal of the AC input power supply and detect at least one of a time when an instantaneous value of the voltage signal reaches a peak, a time when the instantaneous value is a minimum, and a time when the instantaneous value is a predetermined value.