CN101127494A

CN101127494A - Switch power circuit for frequency converter

Info

Publication number: CN101127494A
Application number: CNA2007100436218A
Authority: CN
Inventors: 成爱军; 乔理峰; 金辛海
Original assignee: Shanghai Step Electric Co Ltd
Current assignee: Shanghai Step Electric Co Ltd
Priority date: 2007-07-10
Filing date: 2007-07-10
Publication date: 2008-02-20
Anticipated expiration: 2027-07-10
Also published as: CN100508351C

Abstract

The utility model relates to a switching power supply circuit of the frequency converter, comprising a power conversion circuit, a first PWM control circuit, a main transformer, an isolated feedback circuit, a sampling comparator, a reference voltage circuit, a first rectification circuit, a first filter circuit and a first output; the utility model also comprises at least more than one subordination transformer, a MOS transistor, a second PWM control circuit; wherein an output of the main transformer is connected directly with one or a plurality of inputs of the subordination transformer; the other end of the main transformer is connected with the source electrode of the MOS transistor; meanwhile the drain electrode of the MOS transistor is connected with one or a plurality of other ends of the subordination transformer; the output of the second PWM control circuit is connected with the grid electrode of the MOS transistor; after the output of the subordination transformer passes the second rectifier circuit and the second filter circuit, the second output becomes the input power supply of IGBT. The utility model has the advantages that the design of the main transformer and the subordination transformer is better and the precision is improved.

Description

The switching power circuit of frequency converter

Technical field

The present invention relates to a kind of frequency converter, relate in particular to the switching power circuit of this frequency converter.

Background technology

Frequency converter is by regulating mains frequency to regulate a kind of device of electromotor velocity.Frequency control has speed-regulating range width, the adjusting speed accuracy height, and dynamic response is fast, and low speed torque is good, saves energy, high efficiency, advantage such as easy to use.Use frequency control, motor is moved under energy-conservation rotating speed, but also can improve the control precision of motor speed greatly, promote processing quality and production efficiency.

By Fig. 1, Fig. 2 as seen: the switching power circuit figure of low power frequency conversion device, by power conversion circuit 6, pwm control circuit 7, main transformer 1, isolation feedback circuit 11, sampling comparison circuit 12, reference voltage circuit 13, rectification circuit 8, filter circuit 9 with export 10 and form.The output voltage kind of switching power supply of frequency converter is a lot, positive-negative power, fan and relay power, CPU and peripheral circuit power supply that the comparison amplifying circuit uses, 4 road IGBT driving powers etc. are arranged, big-power transducer IGBT driving power has 8 the tunnel more than, and so to be made on the transformer be very unpractical in Duo output.At first be that pin is too many,, need certain safe distance between the output of transformer, so want empty two pin between every group of output for security consideration.Be the power circuit of a low power frequency conversion device among Fig. 2, used skeleton number of pins is 30; If be applied on the big-power transducer, at least 46 of employed number of pins, so the skeleton of multitube pin is difficult to find.Next is a transformer coiling inconvenience, because the existence of leakage inductance is arranged, under the identical situation of coil turn, the output voltage of inner coil can be littler than skin, because the pressure reduction between the IGBT driving voltage is very big, can not be them around same one deck, so it is bigger with the voltage phase difference that designs to lay out the transformer output voltage that comes, the difficult control of precision.The consequence that causes even can burn out IGBT.

Summary of the invention

The technical issues that need to address of the present invention have provided a kind of switching power circuit of frequency converter, are intended to solve above-mentioned defective.

In order to solve the problems of the technologies described above, the present invention is achieved by the following technical solutions:

The present invention includes: power conversion circuit, first pwm control circuit, main transformer, isolation feedback circuit, sampling comparison circuit, reference voltage circuit, first rectification circuit, first filter circuit and first output; Also comprise at least more than one from transformer, metal-oxide-semiconductor, second pwm control circuit; One end of an output of described main transformer directly links to each other with one or more inputs from transformer, another termination metal-oxide-semiconductor source electrode of main transformer, and the metal-oxide-semiconductor drain electrode links to each other with one or more another inputs from transformer; The output of second pwm control circuit is connected to the grid of metal-oxide-semiconductor; From the output of transformer by second rectification circuit, second filter circuit after, second output is as the input power supply of IGBT;

Compared with prior art, the invention has the beneficial effects as follows: main transformer and from all better designs of transformer, and precision increases.

Description of drawings

Fig. 1 is the switch power module figure of prior art frequency converter;

Fig. 2 is the concrete line map of the Switching Power Supply of prior art frequency converter;

Fig. 3 is a module map of the present invention;

Fig. 4 is a concrete line map of the present invention;

Embodiment

Below in conjunction with accompanying drawing and embodiment the present invention is described in further detail:

As seen from Figure 3: the present invention includes: power conversion circuit 60, first pwm control circuit 70, main transformer 1000, isolation feedback circuit 110, sampling comparison circuit 120, reference voltage circuit 130, first rectification circuit 80, first filter circuit 90 and first output 100; Also comprise at least more than one from transformer 2000, metal-oxide-semiconductor 3000, second pwm control circuit 71; One end of an output of described main transformer 1000 directly links to each other with one or more inputs from transformer 2000, another termination metal-oxide-semiconductor 3000 source electrodes of main transformer 1000, metal-oxide-semiconductor 3000 drain electrodes link to each other with one or more another inputs from transformer 2000; The output of second pwm control circuit 71 is connected to the grid of metal-oxide-semiconductor 3000; Export 101 input power supplys from the output of transformer 2000 by second rectification circuit 81, second filter circuit, 91 backs, second as IGBT;

Described can be a plurality of parallel connections from transformer 2000, and has adopted the topological structure of normal shock;

As seen from Figure 4: original circuit is still used in power conversion circuit, first pwm control circuit, main transformer, isolation feedback circuit, sampling comparison circuit, reference voltage circuit, first rectification circuit, first filter circuit and output among the present invention; The output way of main transformer becomes 5 the tunnel by 8 the tunnel, has reduced by 3 tunnel outputs.The output voltage of main transformer comprises: relatively positive-negative power, fan and the relay power, CPU and the peripheral circuit power supply that use of amplifying circuit, from the driving power of transformer.

The present invention has increased several from transformer, a lot of roads output voltage of an original Switching Power Supply is divided into several small transformers exports.Only need the skeleton of 16 pins to get final product.Pwm control circuit is used for control switch frequency, duty ratio etc.From transformer can be a plurality of parallel connections, and promptly the input of transformer links to each other in twos, and has adopted the topological structure of normal shock.This architectural feature is: transformer imput current is identical with end of the same name with output current, and output voltage and duty ratio and switching frequency are irrelevant.The advantage of this structure is: ripple current is little, the efficient height.

An outlet line figure of main transformer has only drawn among Fig. 4.

Described input voltage from transformer is 26V, is 1: 1 from the turn ratio of transformer, and the output voltage from transformer also is 26V so, by bleeder circuit can obtain-8.2 and the voltage of 17.8V to drive IGBT.Because the average driving current of IGBT is less, so can greater impact not arranged to input voltage.

Claims

1. the switching power circuit of a frequency converter comprises: power conversion circuit (60), first pwm control circuit (70), main transformer (1000), isolation feedback circuit (110), sampling comparison circuit (120), reference voltage circuit (130), first rectification circuit (80), first filter circuit (90) and first output (100); It is characterized in that: also comprise at least more than one from transformer (2000), metal-oxide-semiconductor (3000), second pwm control circuit (71); One end of an output of described main transformer (1000) directly links to each other with one or more inputs from transformer (2000), another termination metal-oxide-semiconductor (3000) source electrode of main transformer (1000), metal-oxide-semiconductor (3000) drain electrode links to each other with one or more another inputs from transformer (2000); The output of second pwm control circuit (71) is connected to the grid of metal-oxide-semiconductor (3000); Export (101) input power supply from the output of transformer (2000) by second rectification circuit (81), second filter circuit (91) back, second as IGBT;

2. the switching power circuit of frequency converter according to claim 1, it is characterized in that: described can be a plurality of parallel connections from transformer (2000), and has adopted the topological structure of normal shock.

3. the switching power circuit of frequency converter according to claim 1 and 2, it is characterized in that: described turn ratio from transformer is 1: 1.