CN203554300U - High-voltage DC power distribution device - Google Patents

Abstract

The utility model discloses a high-voltage DC power distribution device which includes a dynamo-electric-mixing switch unit A, a precharging unit B and a discharging freewheeling-circuit unit C, wherein the main switch unit A includes a contactor T and an insulated-gate bipolar transistor K1; the precharging unit B includes a power resistor R2 and a charging switch K2; and the discharging freewheeling circuit unit C includes a power resistor R3, a discharging switch K3 and a freewheeling diode D. The high-voltage DC power distribution device effectively solves problems that the contactor is easy to be burned and surge currents occur at a switch-on moment when a large capacitor is switched on and problems of residual release of load capacitance when the large capacitor is switched off and compatibility of the power distribution device with different loads in a high-voltage DC power distribution system.

Description

High voltage direct current power distribution equipment

Technical field

The utility model relates to power electronics and electrical technology field, relates in particular to a kind of circuit structure of high voltage direct current power distribution equipment.

Background technology

Along with vehicle improves constantly the dependence of electrical system, the especially appearance of pure electric automobile, the capacity of power distribution system for vehicle improves constantly.Low-voltage direct distribution is because electric current is large, and distributing cable wire diameter is large, and weight is high.In order to alleviate vehicle distributing cable wire diameter and weight thereof, in vehicle, DC distribution voltage improves constantly.Along with the raising of distribution voltage, the problem of bringing is contactor when cutting off load, because of arc extinguishing difficulty even electric arc cannot extinguish and cause probe of contactor sintering, cause contactor to burn.In order to address this problem, can adopt electromechanical switch device, referring to Fig. 1.It normally opens shutoff sequential: after first connecting IGBT during connection, connect contactor; After first turn-offing contactor during shutoff, turn-off IGBT, referring to Fig. 2.

In direct-flow distribution system, between positive and negative busbar, generally there are a large amount of energy storage filter capacitors, as the typical motor load of Fig. 3.Switching device has the impulse current switching device of flowing through connecting moment connecting during this type of load.In high pressure, large electric capacity situation, when switching device is contactor, this impulse current likely makes probe of contactor sintering; When switching device is electromechanical switch device, IGBT likely burns IGBT greatly because connecting loss.

Utility model content

The utility model object is that the defect existing for existing DC switchgear proposes a kind of novel high voltage direct current power distribution equipment, the problem of burning panel switches when efficiently solving the arc extinguishing problem of contactor in high voltage direct current distribution system and connecting capacitive load.

The utility model for achieving the above object, adopts following technical scheme:

A kind of high voltage direct current power distribution equipment, comprise DC power supply and load, characterized by further comprising electromechanical switch unit A, precharge unit B and electric discharge continuous current circuit unit C, after electromechanical switch unit A and precharge unit B parallel connection, be serially connected between the positive output end of DC power supply and the positive input terminal of load, continuous current circuit unit C is in parallel with load in electric discharge, wherein

Electromechanical switch unit A comprises contactor T and insulated gate bipolar transistor K ₁, the input of contactor T connects insulated gate bipolar transistor K ₁collector electrode, the output of contactor T connects insulated gate bipolar transistor K ₁emitter;

Precharge unit B comprises power resistor R ₂with charge switch K ₂, power resistor R ₂with charge switch K ₂series connection;

Electric discharge continuous current circuit unit C comprises power resistor R ₃, discharge switch K ₃and sustained diode, power resistor R ₃with discharge switch K ₃in parallel with sustained diode after series connection, the negative electrode of sustained diode connects the positive input terminal of load, the negative input end of the anodic bonding load of sustained diode.

The beneficial effects of the utility model are as follows:

1, from the life-span of power distribution equipment, topological structure efficiently solves the problem of panel switches arc extinguishing difficulty in cutting-off process, has greatly improved the working life of panel switches under high direct voltage condition.

2, from restriction, connect capacitive load impulse current, topological structure efficiently solves and when connecting capacitive load, has impulse current and cause power distribution equipment to burn problem, has improved the reliability of power distribution equipment.

Accompanying drawing explanation

Fig. 1 is electromechanical switch device circuit structure chart.

Fig. 2 is electromechanical switch device control sequential chart.

Fig. 3 is typical motor load diagram in direct-flow distribution system.

Fig. 4 is the high voltage direct current power distribution equipment main circuit structure figure of the utility model design.

Fig. 5 is the utility model high voltage direct current power distribution equipment control sequential chart.

Fig. 6 is that power distribution equipment is opened shutoff oscillogram under resistive load condition.

Fig. 7 is that power distribution equipment is opened shutoff oscillogram under resistance sense loading condition.

Fig. 8 is that power distribution equipment is opened shutoff oscillogram under capacitive load condition.

Embodiment

Embodiment 1

Below in conjunction with accompanying drawing, the technical solution of the utility model is elaborated:

As shown in Figure 4, high voltage direct current power distribution equipment comprises DC power supply V to circuit of the present utility model _dCand load, also comprise electromechanical switch unit A, precharge unit B and electric discharge continuous current circuit unit C.After electromechanical switch unit A and precharge unit B parallel connection, be serially connected between the positive output end of DC power supply and the positive input terminal of load, continuous current circuit unit C is in parallel with load in electric discharge, ground connection after the negative output terminal of the negative input end connection DC power supply of load.

Wherein electromechanical switch unit A is by contactor T and insulated gate bipolar transistor K ₁composition; The input of contactor T connects insulated gate bipolar transistor K ₁collector electrode after connect the positive output end of DC power supply, the output of contactor T connects insulated gate bipolar transistor K ₁emitter after connect the positive input terminal of load.

Precharge unit B is by power resistor R ₂with charge switch K ₂composition, power resistor R ₂with charge switch K ₂series connection, power resistor R ₂one end connect the positive output end of DC power supply, the other end connects charge switch K ₂input, charge switch K ₂output connect the positive input terminal of load.

Continuous current circuit unit C is by power resistor R in electric discharge ₃, discharge switch K ₃and sustained diode composition.Power resistor R ₃with discharge switch K ₃in parallel with sustained diode after series connection.Discharge switch K ₃input connect the positive input terminal that connects load after the negative electrode of sustained diode, discharge switch K ₃output connect power resistor R ₃one end, power resistor R ₃the other end connect the negative input end that connects load after the anode of sustained diode.

Below introduce the operation principle of the utility model DC switchgear:

During normal work, circuit working state is analyzed:

Fig. 5 is the control sequential schematic diagram of power distribution equipment, t ₀moment control system receives provisioning instruction, and control system receives to be opened after control command, and control system is first sent discharge switch K ₃shutoff instruction, K switch to be discharged ₃close the t having no progeny completely ₁in the moment, control system is sent charge switch K ₂go code and carry out trial charging to load, until load voltage, reach the t after stable ₂in the moment, control system is sent insulated gate bipolar transistor K ₁go code, treat insulated gate bipolar transistor K ₁t after connecting completely ₃in the moment, control system is sent going code of contactor T and is sent charge switch K simultaneously ₂shutoff instruction, now complete whole opening process.

At t ₁and t ₂in the moment, when load is resistive load, expression of load voltage is

u _lOADfor load voltage, V _dCfor direct current system supply voltage, R ₂for the power resistor in precharge unit B, R _lOADfor load resistance; When load is resistance inductive load, expression of load voltage is $u_{\mathrm{LOAD}}\left(t\right)=\frac{V_{\mathrm{DC}}}{R_2+R_{\mathrm{LOAD}}}(1-e^{-\frac{t}{\mathrm{\τ}}})R_{\mathrm{LOAD}}+V_{\mathrm{DC}}{e}^{-\frac{t}{\mathrm{\τ}}},$ U _lOADfor load voltage, V _dCfor direct current system supply voltage, R ₂for the power resistor in precharge unit B, R _lOADfor load resistance, τ=L/ (R ₂+ R _lOAD), L is load inductance; When load is capacitive load, expression of load voltage is

u _cfor load voltage, V _dCfor direct current system supply voltage, τ=R ₂c, R ₂for the power resistor in precharge unit B, C is load capacitance.In order to promote the load compatibility of power distribution equipment, when detecting that load voltage reaches du/dt< ε, control system connects insulated gate bipolar transistor K ₁, du/dt represents load voltage interconversion rate, and ε is set point, and ε has stipulated that precharge unit is load while carrying out trial charging, judges that load reaches stable state and makes power distribution equipment enter the standard of next operation mode.Suppose in high-voltage direct current, supply voltage is V _dC, in system, maximum capacitor is C, when capacitance voltage reaches the a% of supply voltage in trial charging process, thinks that electric capacity precharge is complete, ε can be determined by following formula:

$\mathrm{\&epsiv;}=\frac{V_{\mathrm{DC}}(1-a\%)}{R_{2}C}$

T ₄moment control system receives shutoff instruction, and control system receives turn-offs after instruction, and control system is first sent the shutoff instruction of contactor T, the t after tentaculum waiting turn-offs ₅in the moment, control system is sent insulated gate bipolar transistor K again ₁shutoff instruction, treat insulated gate bipolar transistor K ₁close the t having no progeny completely ₆in the moment, control system is sent discharge switch K ₃go code, so far, complete whole turn off process.

The parameter designing in an example of the present utility model:

Line voltage distribution V _dc=900V, circuit rated current I _n=200A, load resistance R _l=5 Ω, load capacitance C _l=8400 μ F, load inductance L _l=1.6mH;

R ₂=200Ω，R ₃=200Ω；

The contactor T, the insulated gate bipolar transistor K that in the present embodiment, adopt ₁, power resistor R ₂, charge switch K ₂, power resistor R ₃, discharge switch K ₃, sustained diode is ripe conventional products.

Fig. 6, Fig. 7, Fig. 8 be the designed circuit of the utility model while adopting the parameter of design resistive load, resistance inductive load and capacitive load open the oscillogram while turn-offing.As can be seen from the figure:

1, when load is resistive load, resistance inductive load and capacitive load, contactor T opens in shutoff without arcing process, the designed circuit of the utility model efficiently solves the problem of panel switches arc extinguishing difficulty in cutting-off process, has greatly improved the working life of panel switches under high direct voltage condition;

Impulse current when 2, the utility model designed panel switches have effectively suppressed to connect capacitive load, effectively solves the problem of burning of power distribution equipment, has improved the reliability of power distribution equipment;

3, the designed panel switches of the utility model can adapt to resistive load, resistance inductive load and capacitive load, under different loadtypes, according to control strategy, carry out intelligent power distribution, and load compatibility is good.

Claims (1)

1. a high voltage direct current power distribution equipment, comprise DC power supply and load, characterized by further comprising electromechanical switch unit A, precharge unit B and electric discharge continuous current circuit unit C, after electromechanical switch unit A and precharge unit B parallel connection, be serially connected between the positive output end of DC power supply and the positive input terminal of load, continuous current circuit unit C is in parallel with load in electric discharge, wherein

Electromechanical switch unit A is by contactor T and insulated gate bipolar transistor K ₁composition, the input of contactor T connects insulated gate bipolar transistor K ₁collector electrode, the output of contactor T connects insulated gate bipolar transistor K ₁emitter;

Precharge unit B is by power resistor R ₂with charge switch K ₂composition, power resistor R ₂with charge switch K ₂series connection;

Continuous current circuit unit C is by power resistor R in electric discharge ₃, discharge switch K ₃and sustained diode composition, power resistor R ₃with discharge switch K ₃in parallel with sustained diode after series connection, the negative electrode of sustained diode connects the positive input terminal of load, the negative input end of the anodic bonding load of sustained diode.

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