CN208939563U - A kind of output earthing short circuit protection circuit with inhibition frequency converter interference - Google Patents

Abstract

The utility model discloses a kind of with the output earthing short circuit protection circuit for inhibiting frequency converter interference, including short-circuit signal processing circuit, IGBT module gate drive circuit and HF current transformer, the output end of HF current transformer is electrically connected with the input terminal of short-circuit signal processing circuit, the input terminal of the main control unit of the output end electrical connection frequency converter of short-circuit signal processing circuit, and the input terminal of the output end electrical connection IGBT module gate drive circuit of main control unit, the control terminal of the major loop inversion unit of the output end electrical connection frequency converter of IGBT module gate drive circuit, HF current transformer includes ferrite bead and enamel insulated wire, enamel insulated wire is set around on ferrite bead, the lead-out wire of the three-phase output of frequency converter passes through the ferrite bead.The lead-out wire of the three-phase output of frequency converter is passed through from ferrite bead simultaneously, is able to suppress frequency converter and is generated radiation interference and reduce the leakage current of frequency converter.

Description

A kind of output earthing short circuit protection circuit with inhibition frequency converter interference

Technical field

The utility model relates to export earthing short circuit protection circuit, has more specifically to one kind and inhibit frequency converter dry The output earthing short circuit protection circuit disturbed.

Background technique

Currently, in the output earthing short circuit protection circuit of frequency converter, generally using Hall current sensor detection short circuit electricity The method of the saturation voltage drop of stream or detection module.On the one hand, in the method using Hall current sensor detection electric current, Hall electricity Flow sensor price is higher, and needs to increase additional power supply and signal processing circuit, with Hall current sensor phase interworking Connection is closed, causes Global Macros response speed slow in this way, and the high current of ground connection protection level is easily saturated；Using detection The method of the saturation voltage drop of module, circuit itself are poor to the compatibility of various modules, need the saturation according to disparate modules Pressure drop adjustment protection benchmark, that is, the saturation voltage drop of each module is different, and the saturation voltage drop of the module of different manufacturers is not yet Equally, therefore short circuit current is detected with the method for detection saturation voltage drop, it just must be for the saturation voltage drop spy of every kind of module on circuit Property does the adjustment of circuit parameter.On the other hand, the saturation pressure of short circuit current or detection module is detected using Hall current sensor The method of drop, both detection methods do not have the function of inhibiting frequency converter output interference and reduce frequency converter leakage current.

Utility model content

The purpose of the utility model is to provide it is a kind of with inhibit frequency converter interference output earthing short circuit protection circuit, It is able to suppress the radiation interference of frequency converter generation and reduces the leakage current of frequency converter, and production cost is low, fast response time, it is right Module is required without matching.

In order to achieve the above objectives, the solution of the utility model is:

A kind of output earthing short circuit protection circuit with inhibition frequency converter interference, including short-circuit signal processing circuit, IGBT module gate drive circuit and HF current transformer, the output end and short-circuit signal of the HF current transformer are handled The input terminal of circuit is electrically connected, the input of the main control unit of the output end electrical connection frequency converter of the short-circuit signal processing circuit End, and the output end of the main control unit is electrically connected the input terminal of the IGBT module gate drive circuit, the IGBT module The output end of gate drive circuit is electrically connected the control terminal of the major loop inversion unit of the frequency converter, the high-frequency current mutual inductance Device includes ferrite bead and enamel insulated wire, and the enamel insulated wire is set around on the ferrite bead, wherein frequency converter Three-phase output lead-out wire pass through the ferrite bead.

The ferrite bead is nickel-zinc ferrite magnet ring.

After adopting the above structure, the utility model has the following beneficial effects: extraction by being exported in frequency converter three-phase The ferrite bead for being able to suppress frequency converter high frequency radiation interference is added at line, is wound with insulated paint on this ferrite bead Envelope curve, this ferrite bead and enamel insulated wire collectively form a HF current transformer, the master of normal condition low-converter The three-phase output electric current resultant current value of circuit inversion unit is zero, influence electricity in the enamel insulated wire of HF current transformer Stream；When frequency converter three-phase exports ground short circuit, the moment of three-phase output ground short circuit can generate uneven high current, will be in height The low current (short circuit current) of equal proportion is induced in frequency current transformer, short-circuit signal processing circuit detects this short circuit current Amplitude size, outputs signal to main control unit, and main control unit is exported control signal and gives IGBT module gate drive circuit, closed with this The IGBT of the major loop inversion unit of disconnected frequency converter, to be grounded short-circuit protection.

Detailed description of the invention

Fig. 1 is the application circuit that the utility model exports that earthing short circuit protection is applied on frequency converter.

Fig. 2 is the circuit diagram of the utility model.

10- lead-out wire 20- ferrite bead

30- enamel insulated wire

Specific embodiment

In order to which the technical solution of the utility model is explained further, below by specific embodiment come to the utility model into Row elaborates.

As shown in Figs. 1-2, the application circuit that earthing short circuit protection circuit is applied on frequency converter is exported for the utility model Figure, main circuit of frequency converter circuit includes power input connecting terminal, major loop rectification filtering unit, major loop inversion unit, master Control unit and inversion output wiring terminal, the power input connecting terminal be sequentially connected electrically major loop rectification filtering unit, Major loop inversion unit and inversion output wiring terminal.

Power input connecting terminal, the power supply as frequency converter is single-phase or three-phase input supply terminals；Major loop rectification Filter unit is rectified and is filtered for the alternating voltage to input converter, is transformed into DC voltage；Major loop inversion list Member, for rectified and filtered DC voltage to be reverse into the adjustable PWM alternating voltage of three-phase；Inversion output wiring terminal, Pass through lead-out wire 10 respectively for U, V, W three-phase with major loop inversion unit to be electrically connected, then inversion output wiring terminal with External load electrical connection.

The utility model exports earthing short circuit protection circuit, including short-circuit signal processing unit, IGBT module gate-drive Circuit and HF current transformer, the input terminal of the output end electrical connection short-circuit signal processing circuit of HF current transformer are short The input terminal of main control unit, the output end electrical connection of main control unit in the output end electrical connection frequency converter of road signal processing circuit The output end of the input terminal of IGBT module gate drive circuit, IGBT module gate drive circuit is electrically connected major loop inversion unit Control terminal, high-frequency current sensor includes ferrite bead 20 and enamel insulated wire 30, and enamel insulated wire 30 is set around ferrite On magnet ring 20, the lead-out wire 10 drawn respectively from U, V, W three-phase of major loop inversion unit, i.e. three lead-out wires 10 press phase Mutual parallel form passes through ferrite bead 20, is then linked at inversion outlet terminal.Preferably, three extractions above-mentioned Line 10 can also by mutual parallel form on high-frequency mutual inductor one circle of coiling or multiturn, with enhance inhibit frequency converter it is defeated The ability of radiation interference and reduction leakage current out.Wherein, ferrite bead is nickel-zinc ferrite magnet ring.

It, will sense in HF current transformer when any ground short circuit all the way of frequency converter output U, V, W in the utility model A short circuit current should be gone out, short-circuit signal processing circuit receives this short circuit current signal and handled, and treated, and voltage is believed It number is transmitted in main control unit, main control unit exports control signal and gives IGBT module gate drive circuit, and IGBT module gate pole drives Dynamic circuit directly turns off the IGBT of major loop inversion unit, has the function that protect major loop inverter circuit with this.

The utility model induces the coiling of the size selection enamel insulated wire of short circuit current according to HF current transformer The line footpath size of the number of turns and enamel insulated wire.

In the utility model, this short-circuit signal processing circuit includes resistance R1, bias bleeder circuit, comparator reference reference Potential circuit and benchmark decision circuitry, the both ends of enamel insulated wire respectively correspond the two pins of electric connection resistance R1, resistance R1's Second pin ground connection, the short circuit current induced are converted into voltage signal V1 after resistance R1, export U, V, W according to frequency converter Current direction when short-circuit, V1 can be positive voltage, can also be negative voltage.Bias bleeder circuit includes resistance R2, R3, resistance R1's The first pin of first pin electric connection resistance R2, what the second pin of resistance R2 was electrically connected 3rd resistor R3 second draws The positive polarity input terminal of foot, the negative polarity input terminal of comparator U1 and comparator U2, the first pin and Switching Power Supply of resistance R3 VCC electrical connection, wherein the resistance value of resistance R2 is equal to the resistance value of resistance R3, as V1=0V, V2=VCC/2, by V1 from positive voltage Or negative voltage bias is at positive voltage V2.Comparator reference reference voltage circuit includes resistance R4 and zener diode D1, resistance R4 The first pin be electrically connected Switching Power Supply VCC, second pin is electrically connected the cathode and resistance R5 of zener diode D1 First pin, the plus earth of zener diode D1, the first pin of the second pin electric connection resistance R6 of resistance R5, resistance R6 Second pin electric connection resistance R7 the first pin, the second pin ground connection of resistance R7, also, resistance R5, resistance R6 and electricity Two sections of R7 partial pressures of resistance.Benchmark decision circuitry includes two comparator U1, U2 and resistance R8, and the positive polarity input terminal of comparator U1 is electrically connected The second pin of connecting resistance R5, the second pin of the negative polarity input terminal electric connection resistance R6 of comparator U2, obtains difference with this The output end of protection benchmark level voltage value V4, V5 of polar earth short circuit current, comparator U1 and comparator U2 are electrically connected First pin of the second pin of connecting resistance R8, resistance R8 is electrically connected with Switching Power Supply VCC, IGBT module gate drive circuit The input terminal of input terminal and main control unit is electrically connected with the second pin of resistance R8；Wherein, comparator U1 realizes voltage V1 The benchmark judgement of earthing short circuit protection when for positive voltage, i.e., when positive voltage V2 is when VCC/2-VCC is within the scope of this, comparator U1 is acted so that voltage V6 becomes low potential by high potential；Comparator U2 realizes earthing short circuit protection when voltage V1 is negative voltage Benchmark judgement, i.e., when positive voltage V2 is in 0V-VCC/2 (positive voltage V2 do not include VCC/2) this range, comparator U2 movement So that voltage V6 becomes low potential by high potential, voltage signal V6 is sent to IGBT module gate drive circuit and main control list simultaneously In member, main control unit output order gives IGBT module gate drive circuit, and IGBT gate drive circuit is in time by major loop inversion The IGBT of unit is turned off.

The utility model is a kind of with the output earthing short circuit protection circuit for inhibiting frequency converter interference, by frequency converter three The ferrite bead for being able to suppress frequency converter high frequency radiation interference is mutually added at the lead-out wire of output, on this ferrite bead It is wound with enamel insulated wire, this ferrite bead and enamel insulated wire collectively form a HF current transformer.Normal condition Under, the three-phase output electric current resultant current value of the major loop inversion unit of frequency converter is zero, the insulated paint of HF current transformer Non-inductive electric current in envelope curve；Uneven high current is generated when the moment of frequency converter three-phase output ground short circuit, it will be in high-frequency current The low current (short circuit current) of equal proportion is induced in mutual inductor, the amplitude that short-circuit signal processing circuit detects this short circuit current is big It is small, to be grounded short-circuit protection.

The utility model it is a kind of with inhibit frequency converter interference output earthing short circuit protection circuit, compared to it is general suddenly That current sensor, production cost is low, fast response time；Compared to the method for the saturation voltage drop using detection module, this is practical It is novel that each unit is required without matching.In addition, the lead-out wire that the three-phase of frequency converter exports is passed through from ferrite bead simultaneously, energy Frequency converter is enough inhibited to generate radiation interference and reduce the leakage current of frequency converter, structure is simple, strong antijamming capability.

The foregoing is merely the preferred embodiment of the present embodiment, all equalizations done with the utility model claims range Variation and modification, should belong to the scope of the claims of the utility model.

Claims (2)

1. a kind of with the output earthing short circuit protection circuit for inhibiting frequency converter interference, it is characterised in that: at short-circuit signal Manage circuit, IGBT module gate drive circuit and HF current transformer, the output end of the HF current transformer and short circuit The input terminal of signal processing circuit is electrically connected, the main control unit of the output end electrical connection frequency converter of the short-circuit signal processing circuit Input terminal, and the output end of the main control unit is electrically connected the input terminal of the IGBT module gate drive circuit, described The output end of IGBT module gate drive circuit is electrically connected the control terminal of the major loop inversion unit of the frequency converter, the high frequency Current transformer includes ferrite bead and enamel insulated wire, and the enamel insulated wire is set around on the ferrite bead, In, the lead-out wire of the three-phase output of frequency converter passes through the ferrite bead.

2. according to claim 1 a kind of with the output earthing short circuit protection circuit for inhibiting frequency converter interference, feature Be: the ferrite bead is nickel-zinc ferrite magnet ring.