JPH10191638A - Switching power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a switching power supply device in which a countermeasure for suppressing harmonic waves is accomplished without using a large choke coil as a countermeasure against the harmonic waves. SOLUTION: A changeover means SW changes over the connection of two choke coils L1, L2 having two coils on the same core as a countermeasure against harmonic waves to a parallel connection when the power of 100V class AC is supplied from an AC power supply 1 and to a series connection when the power of 200V class AC is supplied from the AC power supply 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching power supply, and more particularly, to a switching power supply in which a choke coil for preventing harmonics is inserted in an AC power supply line.

[0002]

2. Description of the Related Art As shown in FIG. 3, a conventional switching power supply device has a choke coil L101 inserted into one line of an AC power supply and a rectifying and smoothing AC power supply 1 to output a DC voltage. Rectifying means D and smoothing means C
And the power supply circuit 2, and the choke coil L101
Is inserted into one line of the AC power supply, thereby increasing the conduction angle of the current flowing to the AC input and reducing the harmonic component.

[0003]

In a conventional switching power supply device, when an input from an AC 100 V system to an AC 200 V system is supported, a choke coil L101 for harmonic countermeasures is used.
Is required to have twice the current capacity at the time of AC200V system input at the time of AC100V system input, and four times the inductance at the time of AC100V system input at the time of AC200V system input. I had to.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a switching power supply which realizes harmonic countermeasures without increasing the size of the choke coil for harmonic countermeasures.

[0005]

In order to solve the above-mentioned problems, a switching power supply according to the present invention comprises a 100 V AC.
AC power supply for supplying power of the AC and 200 V systems, rectifying means and smoothing means for rectifying and smoothing the AC power supply and outputting a DC voltage, and a power supply for switching the DC voltage output from the rectifying means and smoothing means A circuit, two choke coils inserted between the AC power supply and the rectifier and wound around the same core,
When 0 V system power is supplied, the two choke coils are connected in parallel, and when AC 200 V system power is supplied from the AC power, switching means for switching the two choke coils to connect in series is provided. It is characterized by comprising.

In order to solve the above-mentioned problems, a switching power supply according to the present invention includes a voltage dividing resistor connected between the smoothing means and a power supply circuit for dividing the DC voltage,
Detecting means for detecting the output voltage divided by the voltage dividing resistor, switching means for switching the connection of the two choke coils by the output signal of the detecting means, and when the AC power supply is supplied from the AC power supply. Controls the two choke coils to be connected in parallel, and when the AC power is supplied from the AC power supply, the switching means controls the switch means to connect the two choke coils in series. It is characterized by comprising.

[0007]

Next, a switching power supply according to a first embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a switching power supply according to a first embodiment of the present invention.

As shown in FIG. 1, a switching power supply according to a first embodiment of the present invention includes an AC power supply 1 for supplying AC 100 V and AC 200 V power, and a rectifying and smoothing DC power supply for the AC power supply 1. Rectifying means D and smoothing means C for outputting a voltage, and rectifying means D and smoothing means C
Power supply circuit 2 for switching DC voltage output from
And two choke coils L1 and L2 inserted between the AC power supply 1 and the rectifying means D and wound around the same core, and two choke coils L1 and L2 when the AC power supply 1 supplies 100V AC power. And a switching means SW for switching the two choke coils L1 and L2 so as to be connected in series when the AC 200V power is supplied from the AC power supply 1.

Next, the operation of the switching power supply according to the first embodiment of the present invention will be described with reference to the drawings.

The operation of the switching power supply according to the first embodiment of the present invention, as shown in FIG.
Connection of the choke coils L1 and L2 having two coils,
When AC100V power is supplied from AC power supply 1,
The two choke coils L1 and L2 are connected in parallel, and when AC 200 V system power is supplied from the AC power supply 1, switching is performed by the switching means SW so that the two choke coils L1 and L2 are connected in series.

Next, a switching power supply according to a second embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is a block diagram of a switching power supply according to a second embodiment of the present invention.

As shown in FIG. 2, a switching power supply according to a second embodiment of the present invention includes an AC power supply 1 for supplying AC 100 V and AC 200 V power, and a rectifying and smoothing DC power supply for the AC power supply 1. A rectifier D and a smoother C for outputting a voltage, and resistors R1 and R1 for dividing a DC voltage.
R2, a constant voltage diode ZD for detecting the voltage divided by the resistors R1 and R2, and a constant voltage diode ZD
And a relay RL for switching the connection by the switching control of the transistor Q, and two choke coils L1 and L2 on the same core inserted into one line of the AC power supply.

Next, the operation of the switching power supply according to the second embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 2, the operation of the switching power supply according to the second embodiment of the present invention is as follows. A DC voltage obtained by rectifying and smoothing an input AC voltage 1 by rectifying means D and smoothing means C by resistors R1 and R2. The voltage is divided, and the divided voltage is detected by the Zener voltage of the constant voltage diode ZD.
At the time of V system input, the current does not flow through the winding while the transistor Q remains OFF, and the relay RL does not operate.

As a result, while the choke coils L1 and L2 inserted in one line of the AC power supply remain connected in parallel,
When a C200V system is input, the transistor Q is turned on, a current flows through the winding of the relay RL, and the choke coils L1 and L2 inserted into one line of the AC power supply are connected in series.

[0018]

As described above, according to the switching power supply of the present invention, when the AC 100 V system is input, the AC2
Because the current capacity is twice as large as that at the time of 00V system input, a choke coil for harmonic countermeasures is connected in parallel. At 200V AC input, the inductance is four times that at 100V AC input,
By connecting a choke coil for harmonic countermeasures in series, it is possible to satisfy the requirements of both the current capacity and the inductance, and it is possible to avoid increasing the size of the choke coil for harmonic countermeasures.

[Brief description of the drawings]

FIG. 1 is a block diagram of a switching power supply according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a switching power supply according to a second embodiment of the present invention.

FIG. 3 is a block diagram of a conventional switching power supply device.

[Explanation of symbols]

 Reference Signs List 1 AC power supply 2 Power supply circuit C Smoothing means D Rectifying means L1, L2 Choke coil Q Detecting means (transistor) R1, R2 Voltage dividing resistor RL Switch means (relay) SW Switching means ZD detecting means (constant voltage diode)

Claims (2)

[Claims] 1. An AC power supply for supplying AC100V and AC200V power, a rectifier and a smoother for rectifying and smoothing the AC power and outputting a DC voltage, and an output from the rectifier and smoother. A power supply circuit for switching a DC voltage, two choke coils inserted between the AC power supply and the rectifier and wound around the same core, and the two chokes when the AC power supply of 100 V is supplied from the AC power supply. A switching power supply device comprising: a switching unit configured to connect coils in parallel, and to switch the two choke coils so as to be connected in series when the AC power is supplied from the AC power supply. 2. A dividing resistor connected between the smoothing means and the power supply circuit for dividing the DC voltage, detecting means for detecting an output voltage divided by the dividing resistance, and an output of the detecting means. Switch means for switching the connection between the two choke coils by a signal; and when AC 100 V system power is supplied from the AC power supply, control is performed so that the two choke coils are connected in parallel.
2. The switching power supply device according to claim 1, further comprising: the switching means for controlling the switching means so as to connect the two choke coils in series when system power is supplied.