CN105763037A - Precharge soft starting circuit for three-phase voltage type bi-directional PWM current transformer - Google Patents

Abstract

A precharge soft starting circuit for a three-phase voltage type bi-directional PWM current transformer comprises a first contactor K1, a three-phase diode rectifier bridge TM, a BUCK-BOOST circuit, a second contactor K2 and a DSP, wherein a three-phase alternating voltage source is connected with the alternating-current side of the three-phase diode rectifier bridge TM through the first contactor, the direct-current side of the three-phase diode rectifier bridge TM is connected with the BUCK-BOOST circuit, the BUCK-BOOST circuit is connected with the second contactor K2, the second contactor K2 is connected with the two sides of a direct-current end bus capacitor, and the first contactor K1, the controlled end of the BUCK-BOOST circuit and the second contactor K2 are all connected with the control end of the DSP. Current surge in the starting process is effectively avoided, so that service life is prolonged.

Description

It is applicable to the precharge soft starting circuit of the two-way PWM converter of three-phase voltage type

Technical field

The present invention relates to a kind of three-phase voltage type two-way PWM converter technology, particularly relate to three Phase voltage type two-way PWM converter precharge soft starting circuit.

Background technology

In recent years, along with the development of industry, some high-tech sensitive equipments were to electric energy matter The requirement of amount is more and more higher, in order to obtain the higher quality of power supply, and the two-way PWM of three-phase voltage type Current transformer research is gradually valued by the people.The two-way PWM converter of three-phase voltage type has especially And there is current on line side low harmony wave, unity power factor, energy in bidirectional flow and constant dc The advantages such as pressure, it is possible to realize " the green conversion " of electric energy.

During the two-way PWM converter of three-phase voltage type starts, current impact shows Obtaining increasingly important, excessive dash current can affect the stability of system, shortens making of current transformer The switching tube IGBT of current transformer even can be punctured with the life-span.

Summary of the invention

In order to overcome the start-up course of the two-way PWM converter of existing three-phase voltage type to be easily subject to Rush of current, affect the deficiency in service life, the invention provides one and be prevented effectively from and started The rush of current of journey, increase the service life be applicable to the two-way PWM converter of three-phase voltage type Precharge soft starting circuit.

The technical solution adopted for the present invention to solve the technical problems is:

A kind of precharge soft starting circuit being applicable to the two-way PWM converter of three-phase voltage type, Described soft starting circuit include the first catalyst K1, three-phase diode rectifier bridge TM, BUCK-BOOST step-up/step-down circuit, the second catalyst K2 and dsp processor, three-phase Alternating-current voltage source is connected with the AC of three-phase diode rectifier bridge TM by the first catalyst, The DC side of described three-phase diode rectifier bridge TM and BUCK-BOOST step-up/step-down circuit, Described BUCK-BOOST step-up/step-down circuit and the second catalyst K2 connect, and described second connects Tentaculum K2 is connected with the both sides of DC terminal bus capacitor, described first catalyst K1, The controlled end of BUCK-BOOST step-up/step-down circuit, the second catalyst K2 all with DSP at The control end of reason device connects.

Further, described BUCK-BOOST step-up/step-down circuit include controlled switch pipe IGBT7, Reactor L0, power diode VD and the first electric capacity C0, controlled switch pipe IGBT7 sends out Emitter-base bandgap grading is connected with the positive pole of three-phase diode rectifier bridge TM, the collection of controlled switch pipe IGBT7 Electrode is connected with the negative pole of power diode；Reactor L0 one end and controlled switch pipe IGBT7 Colelctor electrode be connected, the negative pole of the other end of reactor L0 and three-phase diode rectifier bridge TM It is connected；The positive pole of electrochemical capacitor C0 is connected with the positive pole of power diode VD, electrochemical capacitor The negative pole of C0 is connected with the negative pole of three-phase diode rectifier bridge TM, the positive pole of electrochemical capacitor C0 All it is connected with catalyst K2 with negative pole；The grid of described controlled switch pipe IGBT7 is The controlled end of BUCK-BOOST step-up/step-down circuit.

The technology of the present invention is contemplated that: the two-way PWM converter of described three-phase voltage type is pre-charged Soft starting circuit, improves certain reference voltage level in start-up course within a fixed time Mode dc-link capacitance is slowly charged, when dc-link capacitance is charged to reference voltage During value, start the two-way PWM converter of three-phase voltage type, when DC terminal current stabilization one timing Hou Hou, switches DC terminal resistance, increases electric current, enters normal mode of operation.This circuit is special Levy overshoot current when being to start little, start fast.

Described three-phase voltage type two-way PWM converter precharge soft starting circuit, at DC side Use boost booster circuit that dc-link capacitance carries out oblique line formula boost charge, make current transformer Start at nominal target magnitude of voltage, effectively eliminated dash current when starting.

Beneficial effects of the present invention is mainly manifested in: be prevented effectively from start-up course rush of current, Increase the service life.

Accompanying drawing explanation

Fig. 1 is to comprise the present invention to be pre-charged the three-phase voltage type two way convertor of soft starting circuit Schematic diagram.

Fig. 2 is the workflow diagram of precharge soft starting circuit.

Detailed description of the invention

The invention will be further described below in conjunction with the accompanying drawings.

See figures.1.and.2, a kind of be applicable to the pre-of the two-way PWM converter of three-phase voltage type Charging soft starting circuit, described soft starting circuit includes the first catalyst K1, three-phase diode At rectifier bridge TM, BUCK-BOOST step-up/step-down circuit, the second catalyst K2 and DSP Reason device, three-phase alternating current potential source is by the friendship of the first catalyst with three-phase diode rectifier bridge TM Stream side connects, the DC side of described three-phase diode rectifier bridge TM and BUCK-BOOST liter Reduction voltage circuit, described BUCK-BOOST step-up/step-down circuit and the second catalyst K2 connect, Described second catalyst K2 is connected with the both sides of DC terminal bus capacitor, described first catalyst The controlled end of K1, BUCK-BOOST step-up/step-down circuit, the second catalyst K2 are all and DSP The control end of processor connects.

Further, described BUCK-BOOST step-up/step-down circuit include controlled switch pipe IGBT7, Reactor L0, power diode VD and the first electric capacity C0, controlled switch pipe IGBT7 sends out Emitter-base bandgap grading is connected with the positive pole of three-phase diode rectifier bridge TM, the collection of controlled switch pipe IGBT7 Electrode is connected with the negative pole of power diode；Reactor L0 one end and controlled switch pipe IGBT7 Colelctor electrode be connected, the negative pole of the other end of reactor L0 and three-phase diode rectifier bridge TM It is connected；The positive pole of electrochemical capacitor C0 is connected with the positive pole of power diode VD, electrochemical capacitor The negative pole of C0 is connected with the negative pole of three-phase diode rectifier bridge TM, the positive pole of electrochemical capacitor C0 All it is connected with catalyst K2 with negative pole；The grid of described controlled switch pipe IGBT7 is The controlled end of BUCK-BOOST step-up/step-down circuit.

The three-phase voltage type two way convertor of the present embodiment includes three-phase alternating current potential source Es, LCL Wave filter, the first switching tube IGBT1, second switch pipe IGBT2, the 3rd switching tube IGBT3, 4th switching tube IGBT4, the 5th switching tube IGBT5, the 6th switching tube IGBT6, preliminary filling Soft starting circuit, catalyst K3, catalyst K4, catalyst K5, load R7, electric power storage Pond group.

Described precharge soft starting circuit includes: three-phase diode rectifier bridge TM, catalyst K1, Catalyst K2, power diode VD, reactor L0, the 7th switching tube IGBT7 (are i.e. subject to Control switching tube), electrochemical capacitor C0.

Described dsp processor selects the dsp processor of Texas Instrument 2000 series.

The electrolysis electricity of the electrochemical capacitor Cbus on described dc bus, the most optional 10000uF Hold, it is achieved stable DC side voltage and the effect of suppression direct current harmonic wave.

The reactance value of the reactor L0 of DC side and the capacitance of electrochemical capacitor C0 are all chosen bigger Value.

The magnitude of voltage of DC side and relevant, the concrete formula of the dutycycle of the 7th switching tube IGBT7 For:

$U_0=\frac{t_{on}}{t_{off}}E=\frac{1-\mathrm{\α}}{\mathrm{\α}}E$

In formula: U₀For output end voltage, E is three-phase commutation bridge output voltage, t_onIt it is a cycle Interior 7th switching tube ON time, t_offBeing the 7th switching tube turn-off time in the cycle, α is i.e. It is that the 7th switching tube accounts for many ratios in a cycle.

As in figure 2 it is shown, the control method of soft start may is that

A., when the two-way PWM converter of three-phase voltage type starts, three-phase commutation bridge is first detected Whether the voltage of input, i.e. line voltage is stable, if after unlatching limited of magnitude of voltage Stablize in the range of normal voltage value in cycle, open precharge soft starting circuit, if voltage Value fluctuated within limited cycle, beyond normal range, continued three-phase commutation bridge input Voltage detects, and waits that voltage recovers normal.

B. 0～0.01s, catalyst K1, catalyst K2, and initial by DC terminal are closed Voltage reference value is set as 0 volt.Calculate controlled switch pipe IGBT7 control signal PWM ripple Dutycycle, the now dutycycle 0 of PWM ripple, control signal perseverance is low level, controlled opens Close pipe IGBT7 to turn off.

C. at 0.01s～0.02s, the voltage reference value of DC terminal is set as 5 volts, calculates phase The dutycycle answered, when control signal is high level, switching tube IGBT7 turns on, for reactance Device L0 charges.When control signal is low level, switching tube IGBT7 turns off, due to power The one-way conduction effect of diode VD, electric current flows out from the lower end of reactor L0, and upper end is flowed Enter and charge for electric capacity C0 and DC terminal electric capacity Cbus, make magnitude of voltage stable at 5 volts.

D. between Kt～(K+1) t, t is 0.01s, the two-way PWM converter of three-phase voltage type It is 5V that precharge soft starting circuit DC side reference voltage level is set to KU, △ U.Now The voltage of three-phase voltage type two-way PWM converter precharge soft starting circuit DC side is less than KU, dsp processor, according to voltage reference value, adjusts on the 7th switching tube IGBT7 grid The dutycycle of pulse-width signal PWM, makes DC terminal voltage stable in desired value KU.

The most above-mentioned K is positive integer, K takes 1 successively, 2,3 ..., n, the above step of circulation Suddenly, DC terminal voltage is raised to desired value from 0, until DC terminal voltage value stabilization is in target Magnitude of voltage.

F. stable after desired value when DC terminal voltage, dsp processor output two-way low level

Signal at stop catalyst K1, catalyst K2, and export a road high level signal simultaneously Guan Bi DC terminal soft starting circuit catalyst K5 and six road pwm control signals, three-phase voltage Type PWM two way convertor normally works, when the magnitude of voltage of current transformer DC terminal is stablized Reference value limited long-time after, dsp processor exports a road low level signal and closes catalyst K5, exports a road high level signal Guan Bi catalyst K4, increases the charging current of DC terminal, So far three-phase voltage type two-way PWM converter soft start is complete.

Claims (2)

1. it is applicable to a precharge soft starting circuit for the two-way PWM converter of three-phase voltage type, its It is characterised by: described soft starting circuit includes the first catalyst K1, three-phase diode rectifier bridge TM, BUCK-BOOST step-up/step-down circuit, the second catalyst K2 and dsp processor, three Cross streams voltage source is connected by the AC of the first catalyst with three-phase diode rectifier bridge TM Connecing, the DC side of described three-phase diode rectifier bridge TM lifts piezoelectricity with BUCK-BOOST Road, described BUCK-BOOST step-up/step-down circuit and the second catalyst K2 connect, and described Two catalyst K2 are connected with the both sides of DC terminal bus capacitor, described first catalyst K1, The controlled end of BUCK-BOOST step-up/step-down circuit, the second catalyst K2 all with DSP process The control end of device connects.

It is applicable to the precharge of the two-way PWM converter of three-phase voltage type the most as claimed in claim 1 Soft starting circuit, it is characterised in that: described BUCK-BOOST step-up/step-down circuit includes controlled Switching tube IGBT7, reactor L0, power diode VD and the first electric capacity C0, controlled open The emitter stage closing pipe IGBT7 is connected with the positive pole of three-phase diode rectifier bridge TM, controlled switch The colelctor electrode of pipe IGBT7 is connected with the negative pole of power diode；Reactor L0 one end is with controlled The colelctor electrode of switching tube IGBT7 is connected, the other end of reactor L0 and three-phase diode rectification The negative pole of bridge TM is connected；The positive pole phase of the positive pole of electrochemical capacitor C0 and power diode VD Even, the negative pole of electrochemical capacitor C0 is connected with the negative pole of three-phase diode rectifier bridge TM, electrolysis The positive pole of electric capacity C0 and negative pole are all connected with catalyst K2；Described controlled switch pipe IGBT7 The controlled end that grid is BUCK-BOOST step-up/step-down circuit.