CN201690360U

CN201690360U - Shunting type active power factor correcting circuit

Info

Publication number: CN201690360U
Application number: CN2010201579451U
Authority: CN
Inventors: 李钧
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-03-16
Filing date: 2010-03-16
Publication date: 2010-12-29
Anticipated expiration: 2020-03-16

Abstract

The utility model provides a shunting type active power factor correcting circuit, and relates to the input current harmonic suppression of an electrical appliance. The shunting type active power factor correcting circuit comprises a rectifier bridge B1, a rectifier bridge B2, an inductor L, a power switch pipe M, a diode D, an electrolytic capacitor E, a control component 1, a capacitor C, a plurality of sampling resisters R1-R5, and the like. At a peak vulvae region of input sine wave voltage, the first rectifier bridge B1 directly supplies the electricity to a load and charges the capacitor E, wherein the average current is larger; and the active power factor correcting circuit which consists of devices such as the second rectifier bridge B2 and the like supplies the electricity to the load and charges the capacitor E only at a non-voltage peak value region. Therefore, the shunting type active power factor correcting circuit can adopt the inductor L with lower cost and a power device M, thereby not only reducing the cost, but also being capable of obtaining higher DC output voltage compared with the conventional passive or partial active power factor correcting circuit or higher efficiency and reliability compared with the conventional active power factor correcting circuit. The shunting type active power factor correcting circuit can be widely applied to the input electric current harmonic suppression of medium power electrical appliances such as the conversion air conditioner, the plate color TV, the high-frequency induction welder, the switch power supply and the like.

Description

A kind of bypass type APFC

Under technical field the utility model relate to a kind of appliance power factor correcting circuit, the circuit that the Harmonics of Input of transducer air conditioning is suppressed especially.The Harmonics of Input that can be widely used in mid power electrical equipment such as transducer air conditioning, large screen color tv, high-frequency electrical (arc) welding machine, Switching Power Supply, electromagnetic oven suppresses.

The Harmonics of Input of the present transducer air conditioning of background technology suppresses technology except traditional passive, Active Power Factor Correction Technology, and some partly Active Power Factor Correction Technology are also arranged recently.But the common feature of above-mentioned technology is the DC load electric current is all to flow through inductor in the circuit of power factor correction.Because of convertible frequency air-conditioner power bigger, the average current of inductor and power device of flowing through is bigger, for avoiding inductor by dc magnetization, must adopt the iron core of large-size and thicker lead, not only increase cost, weight and volume, but also can cause the decline of output dc voltage after the PPFC (Passive Power Factor Correction) or the decline of APFC efficient and reliability; And existing part Active Power Factor Correction Technology, only in 180 degree scopes of alternating voltage, open no more than 3 current impulse and load current all flows through inductor, need the very big inductor of big inductance quantity, exist not only heavily but also greatly equally, the bigger shortcoming of loss falls in higher cost and inductor voltage.

Summary of the invention is at the deficiency of above-mentioned circuit of power factor correction, the utility model provides a kind of bypass type APFC, only some flows through inductor to its load current, can use less inductor and can satisfy the input power factor and the harmonic requirement of power electrical equipment in the convertible frequency air-conditioner etc., and higher electrical efficiency and reliability are arranged than the power device of low capacity.

The technical scheme that its technical problem that solves the utility model adopts is: this bypass type APFC, comprise two rectifier bridges, inductor, power switch pipe, diode, electrochemical capacitor, control assembly, capacitor and sampling resistor etc., the ac input end that it is characterized in that two rectifier bridges is connected on the input AC electricity loop after the parallel connection respectively, the DC-end also links together, but the anode of first rectifier bridge is directly connected to dc output end DC+, and the anode of second rectifier bridge is through inductor, deliver to dc output end DC+'s again after isolating fly-wheel diode; Power switch pipe is connected between node between inductor and the diode and the DC-end, and the control of controlled assembly is opened or turn-offed; Control assembly is connected with various data sampling resistance respectively, and according to sampled data power switch pipe is carried out pulse width modulation.Input ac voltage is pressed sine law and is changed, at the generating positive and negative voltage peak region by first rectifier bridge directly to the electrochemical capacitor charging with power to the load; Input voltage is lower in non-voltage peak zone, and the booster circuit that is made of second rectifier bridge, inductor, power switch pipe and isolation fly-wheel diode boosts earlier to lower input voltage, again to exporting the electrochemical capacitor charging and powering to the load.In this technical scheme, the average current that provides because of the peak region of input sine wave voltage is big and without inductor and power switch pipe, the inductor so branch is flowed through in the booster circuit and the average current of power device just can significantly reduce, and have realized that the purpose that loss can not reduce output dc voltage falls in the power device and the inductor voltage of available less lighter, lower-cost inductor and small electric current capacity.

The beneficial effects of the utility model are: have than most in the output DC load electric current and directly supplied with by first rectifier bridge, thereby make shunting significantly reduce for the average current of second rectifier bridge, inductor and power switch pipe, can adopt the power device of less lighter, lower-cost inductor and small electric current capacity, both reduced cost and improved efficient, can also obtain than traditional passive or the partly much higher VD of APFC or efficient and the reliability more much higher than traditional APFC.

Description of drawings further specifies the utility model below in conjunction with drawings and Examples.

Accompanying drawing is an electrical block diagram of the present utility model.

Among the figure, AC is an ac input end, and DC+ is the anode of direct current output, and DC-is the negative terminal of direct current output.B1 is first rectifier bridge, and B2 is second rectifier bridge; C is the power factor compensation input filter condenser of holding concurrently; L is the afterflow boost inductor; M is a power switch pipe; The 1st, harmonic wave suppresses control assembly; D is the afterflow isolating diode; E is a direct current energy storage electrochemical capacitor; R1 is the input current sampling resistor, and R2, R3 are the dividing potential drop sampling resistors of VD, and R4, R5 are the dividing potential drop sampling resistors of input ac voltage.

Embodiment is as shown in the figure: ac input end is connected with the ac input end of two rectifier bridge B1 and B2 respectively; The negative terminal of two rectifier bridge B1 and B2 links together, and with the DC-end that is connected to direct current output after sampling resistor R1 connects; The anode of rectifier bridge B1 is directly connected to the DC+ end of direct current output; The anode of B2 is connected with filtering capacitor C with inductor L, and the other end of inductor L is connected with leakage (current collection) utmost point of diode D anode and power switch pipe M; The DC+ end of the negative terminal of diode D and direct current output joins; The other end of the source of power switch pipe M (emission) utmost point and current sampling resistor R1 joins, and is connected to the DC-end of direct current output simultaneously; Be connected to voltage dividing potential drop sampling resistor R2 and R3 between dc output end DC+ and the DC-, its output dc voltage sampled value is delivered to control assembly (1) and is carried out data processing; Exchange input dividing potential drop sampling resistor R4, R5 and filter capacitor C and be connected across between the positive and negative end of second rectifier bridge B2, the AC sampling voltage after R4, R5 dividing potential drop is also delivered to control assembly (1) and is carried out data processing; Between holding with DC-, the DC+ of direct current output also is connected to electrochemical capacitor E.

This circuit is work like this: output dc voltage is set lower slightly than input ac voltage peak value, the alternating voltage of AC input is pressed sine law and is changed, at the generating positive and negative voltage peak region when input voltage is higher than voltage on the output electrochemical capacitor E, first rectifier bridge B1 conducting is also directly exported electrochemical capacitor E and electric to direct current, and bigger supply current can be born in this loop; In non-voltage peak zone, because of input voltage is low rectifier bridge B1 is ended, the booster circuit that is made of second rectifier bridge B2, inductor L, power switch pipe M and isolation sustained diode boosts to lower input voltage earlier, again to exporting the electrochemical capacitor charging and powering to the load.That is to say that two commutating circuits are shunting work.

Current harmonics suppresses principle: control assembly (1) sends pulse with tens thousand of hertz frequency, makes device for power switching M conducting constantly, ends, and makes in the whole periodic regime of input sine wave voltage and can both produce electric current.When switching device M conducting, diode D has isolated output electrochemical capacitor E, input ac voltage forms current loop through the negative terminal that rectifier bridge B2 anode, inductor L, power device M, current sampling resistor R1 get back to rectifier bridge B2, because of the electric current of inductor L must continuously and can not suddenly change, input current progressively increases, and can not cause the current break of power switch pipe M; When control assembly (1) when closing driving pulse, power switch pipe M ends, and inductor L will keep the primary current size and Orientation constant, can only flow to output electrochemical capacitor E and load by sustained diode, that is to say that inductor L has played the effect of boosting with afterflow.Like this, control assembly (1) constantly sends pulse, power switch pipe M conducting constantly or end, flow direction output electrochemical capacitor E and load that the input AC electricity just is able to continuously; The sine voltage signal that control assembly (1) provides according to dividing potential drop sampling resistor R4, R5 can keep guaranteeing that with the input ac voltage homophase with sine law control average current input input current has very low current harmonics; When input current reached limit value, by the current signal that current sampling resistor R1 provides, control assembly (1) can be closed power device M automatically; When output dc voltage near or when reaching setting voltage, control assembly (1) can be transferred narrow conducting pulse duration or shutoff automatically; Thereby possess functions such as overcurrent protection and output over-voltage protection, guarantee the highly reliable work of power switch pipe M.

Claims

1. a bypass type APFC comprises rectifier bridge B1﹠amp; B2, inductor L, power switch pipe M, diode D, electrochemical capacitor E, control assembly 1, capacitor C and sampling resistor R1-R5 etc., the ac input end that it is characterized in that rectifier bridge B1 and B2 is in parallel respectively, the DC-end also links together, but have one to be to be directly connected to dc output end DC+ as the B1 anode, another B2 anode is delivered to dc output end DC+'s again through inductor L, isolation sustained diode; Power switch pipe M is connected with node between inductor L and the diode D; Controlled assembly 1 control of power switch pipe M is opened or is turn-offed; Control assembly 1 is connected with data sampling resistance R 1-R5 respectively, and according to sampled data power switch pipe M is carried out pulse width modulation; In addition, between the positive and negative terminal of rectifier bridge B2, also be connected to capacitor C.