SWITCHING POWER SUPPLY DEVICE

• US 20130127432A1
• Filed: 02/20/2012
• Published: 05/23/2013
• Est. Priority Date: 06/02/2011
• Status: Active Grant

• Current Assignee: Fuji Electric Company Limited (Fuji Electric Systems Company Limited)
• Original Assignee: Fuji Electric Company Limited (Fuji Electric Systems Company Limited)
• Inventors: Chen, Jian
• Granted Patent: US 8,878,506 B2
• Time in Patent Office: Days
• US Class Current: 323/282
• CPC Class Codes: G05F 1/10 Regulating voltage or current G05F1/02 takes precedence; for electric railways B60M3/02
• CPC Class Codes: H02M 1/12 Arrangements for reducing harmonics from ac input or output
• CPC Class Codes: H02M 1/4225 using a non-isolated boost converter
• 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

An object of the present invention is to achieve the reduction of EMI, the improvement of conversion efficiency, and simplification of the input filter. Provided is a switching power supply device that comprises: a chopper circuit that turns on/off the passage of a current to an inductor by means of a switching element; and a switching control circuit that switches the switching element so that an input voltage and an input current have the same phase and a similar shape. The switching control circuit is configured to switch the switching element at a switching frequency that is proportional to an input voltage dependent term of a formula that expresses a third harmonic component of ripples of the current flowing to the inductor.

Claims

1. A switching power supply device, comprising:

a chopper circuit that turns on/off the passage of a current to an inductor by means of a switching element; and

a switching control circuit that switches the switching element so that an input voltage waveform and an input current waveform with respect to a phase of an input voltage become substantially similar in shape,

wherein the switching control circuit is configured to switch the switching element at a switching frequency that is proportional to an input voltage dependent term of a formula that expresses a third harmonic component of ripples of the current flowing to the inductor.

2. The switching power supply device according to claim 1, wherein the switching control circuit has:

an oscillator circuit in which an oscillating frequency is controlled by a switching frequency control voltage and the switching frequency of the switching element is defined by the oscillating frequency; and

a computing circuit that computes the switching frequency control voltage based on an input voltage of the chopper circuit and an output voltage of the chopper circuit.

3. The switching power supply device according to claim 1, wherein the switching control circuit is configured to define a minimum value of the switching frequency.