CN103532410B - A kind of three-level rectifier low switching losses control method - Google Patents

Abstract

A kind of three-level rectifier low switching losses control method disclosed by the invention, is particularly suited for being controlled diode clamp type three-level rectifier.Voltage and current detection device is set between three phase network and three-phase reactor, voltage and current data are obtained by current sensing means measurement, and the output order reference voltage of three phase network is obtained by controller, revise three-phase effective impulse action time, three-phase effective impulse is sent to controller action time, produce output pulse by controller, drive three-level rectifier to carry out low switching losses work.Owing in three phase network, three-phase operates simultaneously, it is equal to three-phase and is injected simultaneously into zero-sequence component, thus change the electric current flowing through midpoint, achieve the balance to DC capacitor voltage to control, and do not change output line voltage virtual value, simplify amount of calculation, by alignment potential fluctuation situation and commutator operating mode, it is carried out low switching losses control, reduce the purpose of rectifier switch loss.

Description

A kind of three-level rectifier low switching losses control method

Technical field

The present invention relates to a kind of three-level rectifier control method, especially one and be applicable to diode clamp type topology knot The three-level rectifier low switching losses control method of structure.

Background technology

Diode clamp type three-level rectifier is with the output of high-quality voltage waveform, relatively low voltage change ratio with to electricity The current harmonics of net injects, and runs occasion obtain a wide range of applications at middle pressure, high-power four-quadrant the most in recent years.But due to The high performance control method comparison of three level converter plants is complicated, additionally, along with power and the raising of voltage, three-level current transformer Loss steeply rises, and skewness weighing apparatus, and these shortcomings limit its further genralrlization application.

Summary of the invention

Technical problem: it is an object of the invention to the weak point overcome in prior art, it is provided that a kind of method is simple, easily-controllable System, the three-level rectifier low switching losses control method that using effect is good.

Technical scheme, the three-level rectifier low switching losses control method of the present invention, including using three phase network and three Phase electrical network be connected three-phase reactor, three-phase reactor connect three-level rectifier, three-level rectifier connect respectively controller, Voltage check device, voltage check device connects controller and DC side load resistance, voltage check device and DC side respectively The D.C. contactor being connected with controller it is connected with between load resistance；Its control method comprises the following steps:

A., voltage and current detection device is set between three phase network and three-phase reactor, is surveyed by current sensing means Measure voltage and current data, and obtained a, b, c three-phase output order reference voltage of three phase network by controller

B. when a phase output order reference voltageTime, make a phase pulse train switching mark F_a=0；When Seasonal a phase pulse train switching mark F_a=1, in like manner according to b, c phase output order reference voltageObtain b, c Phase pulse train switching mark F_b、F_c；

C. by formula:

Calculate A, b, c three-phase effective impulse t action time of three phase network_a、t_b、t_c, in formula: V_dcFor bus voltage value, T_sFor modulation period；

D. when midpoint potential is low, by formula t_min=min (t_a,t_b,t_c) try to achieve three-phase effective impulse time t_a、t_b、t_c Minima t_min, and pass through formulaObtain revised three-phase effective impulse t action time_a′、t_b′、t_c′；

When midpoint potential height, by formula t_max=max (t_a,t_b,t_c) try to achieve three-phase effective impulse time t_a、t_b、t_c's Maximum t_max, and pass through formulaObtain revised three-phase effective impulse t action time_a′、t_b′、 t_c′；

Obtain revised a, b, c three-phase effective impulse t action time_a′、t_b′、t_c', produce output by controller (5) Pulse, drives three-level rectifier to carry out low switching losses work.

Beneficial effect: owing to have employed technique scheme, what its correction was carried out is that in three phase network, three-phase is grasped simultaneously Make, be equal to three-phase and be injected simultaneously into zero-sequence component, thus change the electric current flowing through midpoint, it is achieved that to DC capacitor voltage Balance control, and do not change output line voltage virtual value；Owing to taking the maximum of three-phase effective acting time, minimum when revising Value, reduces the on-off times of the power device of corresponding phase near the positive and negative peak point of commutator phase current, and this measure can significantly reduce The switching loss of commutator；Only need to carry out simple calculations and i.e. can get the three-phase effective impulse time, then by pulse distribution, i.e. The pulsewidth modulation effect compared favourably with space vector of voltage performance can be obtained, while balanced capacitor voltage, reduce switch damage Consumption, such that it is able to significantly reduce processor operand, reduces hardware cost, reduces device temperature rise simultaneously, improve the reliable of device Property.

Accompanying drawing explanation

Fig. 1 is the major loop schematic diagram of the three-level rectifier of the present invention；

Fig. 2 is the three-level rectifier three-phase effective impulse time diagram of the present invention；

Fig. 3 is the three-level rectifier output a phase port alignment voltage oscillogram of the present invention；

Fig. 4 is the three-level rectifier output a phase current waveform figure of the present invention；

Fig. 5 is the three-level rectifier output DC side midpoint potential deviation oscillogram of the present invention；

Fig. 6 is the three-level rectifier output DC voltage oscillogram of the present invention；

Fig. 7 is the three-level rectifier output a phase port alignment voltage oscillogram under traditional method controls.

In figure: 1-three phase network, 2-voltage and current detection device, 3-three-phase reactor, 4-three-level rectifier, 5-is controlled Device processed, 6-voltage check device, 7-D.C. contactor, 8-DC side load resistance.

Detailed description of the invention

Below in conjunction with the accompanying drawings one embodiment of the present of invention is further described:

The three-level rectifier low switching losses control method of the present invention, including three phase network 1, is connected with three phase network 1 Three-phase reactor 3, three-phase reactor 3 connects three-level rectifier 4, and three-level rectifier 4 connects controller 5, voltage respectively Detection device 6, voltage check device 6 connects controller 5 and DC side load resistance 8, voltage check device 6 and DC side respectively The D.C. contactor 7 being connected with controller 5 it is connected with between load resistance 8；Three-level rectifier low switching losses control method walks Rapid as follows:

A., voltage and current detection device 2 is set between three phase network 1 and three-phase reactor 3, is filled by current detecting Put 2 measurements and obtain voltage and current data, and obtain a, b, c three-phase output order of three phase network 1 with reference to electricity by controller 5 Pressure

B. when a phase output order reference voltageTime, make a phase pulse train switching mark F_a=0；When Seasonal a phase pulse train switching mark F_a=1, in like manner according to b, c phase output order reference voltageObtain b, c Phase pulse train switching mark F_b、F_c；

C. by formula:

Calculate Three phase network a, b, c three-phase effective impulse t action time_a、t_b、t_c, Fig. 2 is to show the three-level rectifier three-phase effective impulse time It is intended to, in formula: V_dcFor bus voltage value, T_sFor modulation period；

D. when midpoint potential is low, by formula t_min=min (t_a,t_b,t_c) try to achieve three-phase effective impulse time t_a、t_b、t_c Minima t_min, and pass through formulaObtain revised three-phase effective impulse t action time_a′、t_b′、t_c′；

When midpoint potential height, by formula t_max=max (t_a,t_b,t_c) try to achieve three-phase effective impulse time t_a、t_b、t_c's Maximum t_max, and pass through formulaObtain revised three-phase effective impulse t action time_a′、t_b′、 t_c′；

Obtain revised a, b, c three-phase effective impulse t action time_a′、t_b′、t_c', produce output arteries and veins by controller 5 Punching, drives three-level rectifier 4 to carry out low switching losses work.

As it is shown in figure 1, the three-level rectifier that converter is diode clamp type in described three-level rectifier, three The AC of level rectifier 4 is connected to three phase network 1 by three-phase reactor 3, three-phase reactor 3 and three phase network 1 it Between connect and have the detection device 2 of voltage and current；The DC side of three-level rectifier 4 is connected to direct current by D.C. contactor 7 Lateral load resistance 8, the DC side in three-level rectifier 4 is also associated with voltage check device 6；Voltage, current sensing means 2 and The signal that voltage check device 6 detection obtains is sent in controller 5, the pulsed drive three-level rectifier 4 of controller 5 output, There is a road signal for controlling D.C. contactor 7 simultaneously.Wherein dc bus command voltage V_dcFor 300V, three-phase 190V is used to enter Row controlled rectification obtains, electric capacity C₁、C₂Value is 5000uF, T_a1、T_a2、T_a3、T_a4、T_b1、T_b2、T_b3、T_b4、T_c1、T_c2、T_c3、T_c4Adopt With the insulated gate bipolar transistor of 1200V/200A, D_a1、D_a2、D_b1、D_b2、D_c1、D_c2Use fast two poles again of 1200V/200A Pipe, DC side uses resistance as rectifier load, and wherein resistance is 16 ohm, and switching frequency elects 2000 hertz as, specifically walks Rapid as follows:

I. in zero moment, three-level rectifier 4 is by uncontrollable rectifier, and DC bus-bar voltage is charged to 135V；

II. after DC bus-bar voltage reaches 135V, three-level rectifier 4 puts into operation, and controller 5 is according to given voltage DC bus-bar voltage is regulated to 300V after overvoltage, current double closed-loop control by 300V；

III. after DC bus-bar voltage is stable, putting into DC side ohmic load 8, now three-level rectifier 4 is due to load Variation DC bus-bar voltage declines, and causes the dynamic regulation of voltage, current double closed-loop；

IV. during the regulation of voltage, current double closed-loop, DC capacitor voltage fluctuates, and voltage check device 6 is surveyed Feed back to controller 5 is carried out neutral-point potential balance regulation after measuring magnitude of voltage, carry out the effective of switching loss reduction simultaneously Burst length adjusts；

V. send into after the adjustment of three-phase effective impulse time in controller 5 hardware, produce pulse output and drive three level rectifyings Device 4, the three-level rectifier low switching losses reaching simplification controls.

Fig. 2 show diode clamp type three-level rectifier three-phase effective impulse time diagram, uses control of the present invention The three-phase effective impulse time of the three-level rectifier under Zhi, it is the loading time that DSP hardware unit is supported, in calculating directly Corresponding.

Fig. 3 show diode clamp type three-level rectifier output a phase port alignment voltage oscillogram；Use this Three-level rectifier output voltage, current waveform under bright control are good, and switch motion number of times significantly reduces, and switching loss is relatively Low.

Fig. 4 show the diode clamp type three-level rectifier output a phase current waveform figure of the present invention, uses the present invention Three-level rectifier output current wave under Kong Zhiing is sinusoidal, and waveform quality is higher.

Fig. 5 show the diode clamp type three-level rectifier output DC side midpoint potential deviation oscillogram of invention, Three-level rectifier DC side midpoint potential deviation under using the present invention to control is the least, fluctuates near zero, without accumulation skew Phenomenon, shows that midpoint potential deviation controls preferably.

The diode clamp type three-level rectifier output DC voltage that Fig. 6 show under control method of the present invention controls Oscillogram, the three-level rectifier DC voltage under the present invention controls makees fuctuation within a narrow range, table around given DC voltage 300V Bright DC voltage deviation is the least, and voltage regulation result is good.

Fig. 7 show the diode clamp type three-level rectifier a phase port alignment voltage wave used under Traditional control Shape figure；By waveform in figure it can be seen that commutator a phase switch motion number of times is more more than the present invention, damage at large-power occasions switch Consume higher.

Claims (1)

1. a three-level rectifier low switching losses control method, is connected with three phase network (1) including three phase network (1) Three-phase reactor (3), three-phase reactor (3) connects three-level rectifier (4), and three-level rectifier (4) connects controller respectively (5), voltage check device (6), voltage check device (6) connects controller (5) and DC side load resistance (8), voltage respectively It is connected with, between detection device (6) and DC side load resistance (8), the D.C. contactor (7) being connected with controller (5)；Its feature exists In: control method comprises the following steps:

A., voltage and current detection device (2) is set between three phase network (1) and three-phase reactor (3), by voltage and electricity Flow detection device (2) is measured and is obtained voltage and current data, and is obtained a, b, c three-phase of three phase network (1) by controller (5) Output order reference voltage

B. when a phase output order reference voltageTime, make a phase pulse train switching mark F_a=0；WhenTime Make a phase pulse train switching mark F_a=1, in like manner according to b, c phase output order reference voltageObtain b, c phase Pulse train switching mark F_b、F_c；

C. by formula:

$t_a=T_s\·F_a+\frac{V_{a\_ref}^{*}\·T_s}{V_{dc}},t_b=T_s\·F_b+\frac{V_{b\_ref}^{*}\·T_s}{V_{dc}},t_c=T_s\·F_c+\frac{V_{c\_ref}^{*}\·T_s}{V_{dc}},$ Calculate a, b, C three-phase effective impulse t action time_a、t_b、t_c, in formula: V_dcFor bus voltage value, T_sFor modulation period；

D. when midpoint potential is low, by formula t_min=min (t_a,t_b,t_c) try to achieve three-phase effective impulse time t_a、t_b、t_c? Little value t_min, and pass through formula $\left\{\begin{array}{c}{t}_a^{\′}=t_a-t_{min}\\ t_b^{\′}=t_b-t_{\min }\\ t_c^{\′}=t_c-t_{\min }\end{array}\right.$ Obtain revised three-phase effective impulse t ' action time_a、t′_b、t′_c；

When midpoint potential height, by formula t_max=max (t_a,t_b,t_c) try to achieve three-phase effective impulse time t_a、t_b、t_cMaximum Value t_max, and pass through formula $\left\{\begin{array}{c}{t}_a^{\′}=t_a-t_{max}+T_s\\ t_b^{\′}=t_b-t_{max}+T_s\\ t_c^{\′}=t_c-t_{\max }+T_s\end{array}\right.$ Obtain revised three-phase effective impulse t ' action time_a、t′_b、t′_c；

Obtain revised a, b, c three-phase effective impulse t ' action time_a、t′_b、t′_c,

Produce output pulse by controller (5), drive three-level rectifier (4) to carry out low switching losses work.