CN103063945B - Flexible direct current transmission sub-module test device and test method thereof - Google Patents

Abstract

The invention relates to a flexible direct current transmission sub-module test device and a test method thereof. The test device comprises a direct current power supply, a resistor-switch series branch I, a tested-object sub-module SM1, a tested-object sub-module SM2 and a resistor-switch series branch II, wherein the resistor-switch series branch I, the tested-object sub-module SM1, the tested-object sub-module SM2 and the resistor-switch series branch II are connected with the direct current power supply in sequence and in parallel. A switch is connected between the direct current power supply and the resistor-switch series branch I, and a resistor is connected with the switch in parallel. Another switch is connected between direct current ends of the tested-object sub-module SM1 and the tested-object sub-module SM2. A load electric reactor is connected between anode ends of the tested-object sub-module SM1 and the tested-object sub-module SM2, a sensor is connected with grounding ends of the tested-object sub-module SM1 and the tested-object sub-module SM2, and a microprogrammed control unit (MCU) respectively communicates with the tested-object sub-module SM1 and the tested-object sub-module SM2 through optical fibers. According to the test method, pulse-width modulation (PWM) pulse of the test device is adjusted to carry out a thermal stability test to the tested-object sub-module SM1 and the tested-object sub-module SM2 and a test to a single-module insulated gate bipolar translator (IGBT) device. Through varied and flexible test modes and test return circuits, assessment of sub-modules is truly realized, and engineering application safety and reliability are improved.

Description

A kind of flexible direct current transmission sub-module test unit and test method thereof

Technical field

The present invention relates to Power System Flexible power transmission and distribution, power electronics and high voltage power transmission technical field, be specifically related to a kind of flexible direct current transmission sub-module test unit and test method thereof.

Background technology

Under the present situation that customary DC technology of transmission of electricity is day by day ripe, along with the development of flexible direct current emerging technology and the demand in market, transverter develops into many level by two level and three level.Both at home and abroad by modularization multi-level converter (Modular Multilevel Converter, be called for short MMC) be successfully applied in engineering as a kind of new multilevel converter, traditional multi-level inverter switching frequency is low, switching loss is little, high frequency noise is low, voltage change ratio is little advantage that it has had concurrently.Because domestic MMC technology is also in initial stage; this certainly will need supporting test unit and support, by carrying out actual test, analysis, calculating to MMC submodule electric current and voltage stress, component failure rate, device loss and Control protection ability etc. as design.Guarantee reliability and the security of autonomous Design product.

Summary of the invention

For the deficiencies in the prior art, the invention provides a kind of flexible direct current transmission sub-module test unit and test method thereof, the present invention both can complete the long-term electric steady state test continued, and also can carry out the electric performance test of moment transient state.Really reach the examination to submodule by changeable test mode flexibly and test loop, improve the safety and reliability of engineer applied.

The object of the invention is to adopt following technical proposals to realize:

A kind of flexible direct current transmission sub-module test unit, its improvements are, described test unit comprises direct supply, the resistance in parallel successively with direct supply-switch series arm I, test product submodule SM1, test product submodule SM2 and resistance switch series arm II; Between direct supply and resistance-switch series arm I, be connected with a switch, have a resistance and this switch in parallel; Another switch is connected with in the DC terminal of test product submodule SM1 and test product submodule SM2; Be connected with load reactance device at the positive terminal of test product submodule SM1 and test product submodule SM2, earth terminal is connected with sensor, and has microcontroller to be communicated with test product submodule SM2 with test product submodule SM1 respectively by optical fiber.

Wherein, described direct supply, resistance-switch series arm I, test product submodule SM1, test product submodule SM2, resistance switch series arm II and the equal ground connection of sensor; Described resistance-switch series arm I and resistance switch series arm II forms by the switch of resistance and series connection with it; Described sensor is Hall current sensor.

Wherein, described test product submodule SM1 and test product submodule SM2 includes direct current capacitors and the half-bridge structure in parallel with it; Described half-bridge structure is made up of two IGBT units in series, between direct current capacitors and half-bridge structure, be parallel with equalizing resistance; Each IGBT unit includes antiparallel upper pipe IGBT device and diode and antiparallel lower pipe IGBT device and diode; Submodule controller is all parallel with test product submodule SM1 and test product submodule SM2.

The present invention is based on the test method of a kind of flexible direct current transmission sub-module test unit that another object provides, its improvements are, described method, by regulating the pwm pulse of test unit, carries out heat stabilization test and single module IGBT device testing experiment to test product submodule SM1 and test product submodule SM2.

Wherein, described heat stabilization test adopts the H bridge mode of test unit, by regulating the phase differential between the dutycycle of pwm pulse and test product submodule, what control IGBT device turns on and off time span, affect the thermocurrent and peak point current that flow through IGBT device and direct current capacitors, wherein thermocurrent≤600A, peak point current≤1800A; By obtaining overcurrent protection value and the IGBT device loss of IGBT device driving to the mutation analysis of above-mentioned two kinds of electric currents, comprise the steps:

A, direct supply are respectively the direct current capacitors charging of test product submodule SM1 and test product submodule SM2;

When B, direct current capacitors charge to 700V, give enable signal and microcontroller and test product submodule SM1 are communicated with test product submodule SM2 foundation;

The switch of C, closed resistance-switch series arm I, and the charging connecting valve opening test product submodule SM1 and SM2 DC terminal, make to form resonant tank between test product submodule SM1 and SM2 and load reactance device;

The fpga chip of D, microcontroller sends the pwm pulse unlock command of test product submodule SM1 and SM2, by the PWM pulsewidth width t in each cycle in microcontroller inquiry sine table, and determining pwm pulse rising edge and negative edge moment in each cycle by formula (10000-t)/2 and (10000+t)/2, in triggers test product submodule SM1 and SM2, each IGBT device turns on and off;

After E, test product submodule SM1 and SM2 internal receipt to the pwm pulse unlock command of microcontroller, order about IGBT and driven control is turned on and off to each IGBT device in test product submodule SM1 and SM2;

F, rising DC capacitor voltage make it reach rated voltage, and resonant tank enters steady state (SS);

G, by the electric current of each IGBT device in test product submodule SM1 and SM2 and magnitude of voltage, determine the loss of each IGBT device in test product submodule SM1 and SM2.

Wherein, in described step D, draw sine table according to the rising edge detected and negative edge:

5000×sin(2π×i/20+2π/20/2)+5000,i＝0,1,2…19 ①；

Wherein: i indicating impulse number, in one-period, 20 pwm pulses are had.

Wherein, in described step G, in test product submodule SM1 and SM2, each IGBT device comprises on-state loss and switching loss; 2. and 3. the calculating of on-state loss and switching loss drawn by following formula:

Pcon＝Vce×Ic ②；

Psw＝fsw×(Eon+Eoff) ③；

Wherein: Pcon represents the on-state loss of IGBT device; Vce represents the instantaneous on-state voltage drop of IGBT device; Ic represents the instantaneous on state current flowing through IGBT device; Psw represents the switching loss of IGBT device; Fsw represents that switching frequency Eon and Eoff of IGBT device represents that IGBT device turns on and off the energy in moment respectively.

Wherein, described single module IGBT device testing experiment is tested separately each test product submodule, and single module IGBT device testing experiment comprises the test of overcurrent superpotential and the short-circuit current test of single module IGBT device; Perform following operation before the test:

I, load inductance is connected in parallel on the upper pipe IGBT device two ends of test product submodule, and keeps pipe IGBT device to be up and down in blocking;

II, direct supply are the direct current capacitors charging of single test product submodule;

The switch that III, disconnection are connected with direct supply;

IV, the pulse producer be connected is driven to produce pipe IGBT device conducting under monopulse or the single test product submodule of Two-pulse triggering by with single test product submodule IGBT;

V, measure pipe IGBT device under single test product submodule and turn off superpotential, excess current and di/dt protection value.

Wherein, the overcurrent of described IGBT device and superpotential test comprise the steps:

(1) calculate pulse producer export bi-pulse width and carry out actual test, described bi-pulse width t is expressed from the next:

$t=\frac{\mathrm{Ic}*L}{U}$ ④；

Wherein: Ic represents the maximum current value that needs reach; L represents load inductance value; U represents the maximum voltage value that needs apply;

(2) trigger pipe IGBT device under single test product submodule to open and turn off and produce excess current and superpotential;

(3) determine the loop stray inductance value Ls of single test product submodule, represent with following formula: 5.;

Wherein: Us represents stray inductance induced voltage; The escalating rate of electric current I c when di/dt represents that lower pipe IGBT device is opened.

Wherein, the short-circuit current test of described IGBT device comprises the steps:

(1) pipe IGBT device on the single test product submodule of low self-induction wire short circuit is adopted;

(2) pulse producer produces monopulse, and single pulse width is by 3. formula calculating;

(3) pipe IGBT device make this pipe generation instantaneous short circuit under the single test product submodule of monopulse triggering and conducting, tolerance moment kA level electric current, makes pipe IGBT device under single test product submodule drive and starts di/dt protection instantaneously.

Compared with the prior art, the beneficial effect that the present invention reaches is:

1, flexible direct current transmission sub-module test unit provided by the invention, by regulating pwm pulse, can realize examination and analyses SM being carried out to voltage, electric current and thermal stress under different operating mode.

2, heat stabilization test adopts H bridge mode, and by regulating the phase differential between the dutycycle of PWM and submodule, control IGBT opens turn-off time length, affects the thermocurrent and peak point current that flow through IGBT and capacitor.By obtaining actual overcurrent protection value and the IGBT device loss of IGBT driving to the mutation analysis of above-mentioned two kinds of electric currents, the energy that in test, loop consumes is compensated by this device and reaches balance.The advantage main manifestations of heat stabilization test be following some:

1) by the parameter of regulating load reactor L and controller, the submodule current stress test of wide region can be realized, check tolerance situation and the hotspot's distribution of IGBT device and capacitor;

2) applying of high direct voltage, withstand voltage between the end examining capacitor internal coat of metal core and IGBT device, realize the voltage stress test of antithetical phrase inside modules device;

3) resonant topology loop can realize comparatively real Electromagnetic Interference Test between intermodule and inside modules device, checks the serious point of electromagnetic interference (EMI) that design exists;

4) adjustment of phase differential in heat stabilization test, under can be implemented in low watt current, to the examination of device peak electric current tolerance.

3, the testing experiment of single module IGBT device adopts single module series system; under high pressure complete the relay protections such as the short circuit of IGBT, excess current and superpotential; the di/dt protection value of test I GBT, overcurrent protection value (actual monitoring VCE voltage), maximum shutoff overvoltage value and loop stray inductance under actual condition, and then infer the self-induction of capacitor.Single module test advantage mainly contain following some:

1) by superpotential and the anti-phase restoring current of generation in test, IGBT can be checked to drive overvoltage protection value and accurately loop stray inductance accurately; And impact each other;

2) overcurrent test under high/low temperature, can test out the overcurrent protection scope that IGBT drives more accurately, make it be limited in the safety operation area of IGBT;

3) short-circuit current test, the width that can adjust pulse accurately measures the di/dt tetra-segment protect value of IGBT driving, limits the irreversible damage of too fast current changing rate to IGBT.

4, the present invention provides reliable test method to inspection IGBT device matching property aspect, the advantage that test unit has versatility and arranges flexibly.

Accompanying drawing explanation

Fig. 1 is flexible direct current transmission sub-module test unit schematic diagram provided by the invention;

Fig. 2 is single module device detection circuit theory diagrams provided by the invention.

Embodiment

Below in conjunction with accompanying drawing, the specific embodiment of the present invention is described in further detail.

As shown in Figure 1, test unit comprises direct supply, the resistance in parallel successively with direct supply-switch series arm I, test product submodule SM1, test product submodule SM2 and resistance switch series arm II to flexible direct current transmission sub-module test unit schematic diagram; Between direct supply and resistance-switch series arm I, be connected with a K switch c, have a resistance Rc in parallel with this K switch c; Be connected with another K switch 3 in the DC terminal (F and G) of test product submodule SM1 and test product submodule SM2, and have load reactance device and connect and switch ends; Hall current sensor is connected with at the earth terminal (H and I) of test product submodule SM1 and test product submodule SM2; Test unit and microcontroller adopt Fiber connection to communicate, all reliable and secure ground connection of earth terminal needed for test unit.

Test product submodule SM1 and test product submodule SM2 includes direct current capacitors C and the half-bridge structure in parallel with it; Described half-bridge structure is made up of two IGBT units in series, is parallel with equalizing resistance R between direct current capacitors C and half-bridge structure; Each submodule unit includes pipe IGBT device T1 and fly-wheel diode and lower pipe IGBT device T2 and fly-wheel diode; Test product submodule SM1 and test product submodule SM2 adopts Fiber connection by the key control unit of microcontroller and its inside.

Resistance-switch series arm I is made up of the K switch 1 of resistance R1 and series connection with it, and resistance switch series arm II is made up of the K switch 2 of resistance R2 and series connection with it.

Comprise the steps: when carrying out heat stabilization test

A, direct supply are that the direct current capacitors C of test product submodule SM1 and SM2 charges simultaneously;

After B, draw-out power supply normally start, give test product submodule SM1 and SM2 enable signal, microcontroller is set up with test product submodule SM1 with SM2 and communicates;

The K switch 1 of C, closed resistance-switch series arm I, and the charging connecting valve Kc opening test product submodule SM1 and SM2, make to form resonant tank between submodule SM1 and SM2 and load reactance device;

D, micro control unit MCU core devices FPGA send the pwm pulse unlock command of test product submodule SM1 and SM2, and pwm pulse is made up of the carrier wave of 1KHz and the modulating wave of 50Hz, has 20 pulses in one-period.

Pulse be by the timer in microcontroller produce 1 1KHz Interruption inquiry sine table mode realize, the radix of each pwm pulse is 10000, so resolution is 0.1us.1. sine table can be drawn out by following formula, pwm pulse width t in sine table in each cycle, calculated rising edge and the negative edge moment of pwm pulse by formula (10000-t)/2 and (10000+t)/2, what complete each IGBT device in test product submodule SM1 and SM2 turns on and off operation;

5000×sin(2π×i/20+2π/20/2)+5000,i＝0,1,2…19 ①；

Wherein: i indicating impulse number, in one-period, 20 pwm pulses are had.

After E, test product submodule SM1 and SM2 internal receipt to the pwm pulse unlock command of microcontroller, order about IGBT and driven control is turned on and off to each IGBT device in test product submodule SM1 and SM2;

The voltage of F, the respectively direct current capacitors of rising test product submodule SM1 and SM2, to rated voltage, guarantees that resonant tank enters steady state (SS);

Dutycycle and phase differential by adjusting pwm pulse in G, process of the test realize the change of current peak and effective value.In this operational process, can carry out the calculating of core devices IGBT loss according to real data, wherein 2. and 3. the calculating of on-state loss and switching loss drawn respectively by following formula:

Pcon＝Vce×Ic ②；

Psw＝fsw×(Eon+Eoff) ③；

Wherein: Pcon represents the on-state loss of IGBT device; Vce represents the instantaneous on-state voltage drop of IGBT device; Ic represents the instantaneous on state current flowing through IGBT device; Psw represents the switching loss of IGBT device; Fsw represents the switching frequency of IGBT device; Eon and Eoff represents that IGBT turns on and off the energy in moment respectively.

Single module IGBT device testing experiment is tested separately each test product submodule, and this test comprises the test of overcurrent superpotential and the short-circuit current test of single module IGBT device; As shown in Figure 2, following operation is performed before the test:

I, load inductance L is connected in parallel on the upper pipe IGBT device two ends of single test product submodule, and keeps pipe IGBT device to be up and down in blocking;

II, direct supply are that the direct current capacitors C of single test product submodule charges, and progressively reach the magnitude of voltage of testing requirements;

The K switch c that III, disconnection are connected with direct supply;

IV, trigger lower pipe IGBT device conducting by driving the external auxiliary adjustable pulse generator be connected to produce monopulse (or dipulse) with single test product submodule IGBT;

V, accurately measurement IGBT turn off superpotential, excess current and di/dt protection value.

Single module IGBT device testing experiment comprise single module IGBT device overcurrent superpotential test and short-circuit current test.

One, the overcurrent superpotential test of IGBT device comprises the steps:

(1) calculate pulse producer export bi-pulse width and carry out actual test, described bi-pulse width t is expressed from the next:

$t=\frac{\mathrm{Ic}*L}{U}$ ④；

Wherein: Ic represents the maximum current value that needs reach; L represents load inductance value; U represents the maximum voltage value that needs apply;

(2) under triggering single test product submodule, pipe IGBT device T2 opens shutoff, produces excess current and superpotential.

(3) stray inductance of submodule home loop stray electrical inductance value Ls(mainly direct current capacitors and busbar thereof is determined), represent with following formula:

$\mathrm{Ls}=\mathrm{Us}\×\frac{1}{\mathrm{di}/\mathrm{dt}}$ ⑤；

Wherein: Us represents stray inductance induced voltage; The escalating rate of electric current I c when di/dt represents that lower pipe IGBT device is opened.

Two, the short-circuit current test of IGBT device comprises the steps:

(1) pipe IGBT device T1 in the single test product submodule of low self-induction wire short circuit is adopted;

(2) pulse producer produces monopulse, and single pulse width is by 3. formula calculating;

(3) pipe IGBT device T2 make this pipe generation instantaneous short circuit under the single test product submodule of monopulse triggering and conducting, tolerance moment kA level electric current, makes lower pipe IGBT device T2 drive and starts di/dt protection instantaneously, ensure that IGBT device T1 and T2 is not damaged.

Flexible direct current transmission sub-module test unit provided by the invention, by regulating pwm pulse, can realize examination and analyses SM being carried out to voltage, electric current and thermal stress under different operating mode.Reliable test method is provided to inspection IGBT device matching property aspect, the advantage that test unit has versatility and arranges flexibly.

Finally should be noted that: above embodiment is only in order to illustrate that technical scheme of the present invention is not intended to limit, although with reference to above-described embodiment to invention has been detailed description, those of ordinary skill in the field are to be understood that: still can modify to the specific embodiment of the present invention or equivalent replacement, and not departing from any amendment of spirit and scope of the invention or equivalent replacement, it all should be encompassed in the middle of right of the present invention.

Claims (5)

1. the test method of a flexible direct current transmission sub-module test unit, it is characterized in that, described test unit comprises direct supply, the resistance in parallel successively with direct supply-switch series arm I, test product submodule SM1, test product submodule SM2 and resistance switch series arm II; Between direct supply and resistance-switch series arm I, be connected with a switch, have a resistance and this switch in parallel; Charging connecting valve is connected with in the DC terminal of test product submodule SM1 and test product submodule SM2; Be connected with load reactance device at the positive terminal of test product submodule SM1 and test product submodule SM2, earth terminal is connected with sensor, and has microcontroller to be communicated with test product submodule SM2 with test product submodule SM1 respectively by optical fiber;

Described direct supply, resistance-switch series arm I, test product submodule SM1, test product submodule SM2, resistance switch series arm II and the equal ground connection of sensor; Described resistance-switch series arm I and resistance switch series arm II forms by the switch of resistance and series connection with it; Described sensor is Hall current sensor;

Described test product submodule SM1 and test product submodule SM2 includes direct current capacitors and the half-bridge structure in parallel with it; Described half-bridge structure is made up of two IGBT units in series, between direct current capacitors and half-bridge structure, be parallel with equalizing resistance; Each IGBT unit includes antiparallel upper pipe IGBT device and diode and antiparallel lower pipe IGBT device and diode; Test product submodule SM1 and test product submodule SM2 is all parallel with submodule controller;

Described method, by regulating the pwm pulse of test unit, carries out heat stabilization test and single module IGBT device testing experiment to test product submodule SM1 and test product submodule SM2;

Described heat stabilization test adopts the H bridge mode of test unit, by regulating the phase differential between the dutycycle of pwm pulse and test product submodule, what control IGBT device turns on and off time span, affects the thermocurrent and peak point current that flow through IGBT device and direct current capacitors; By obtaining overcurrent protection value and the IGBT device loss of IGBT device driving to the mutation analysis of above-mentioned two kinds of electric currents, comprise the steps:

A, direct supply are respectively the direct current capacitors charging of test product submodule SM1 and test product submodule SM2;

When B, direct current capacitors charge to 700V, give enable signal and microcontroller and test product submodule SM1 are communicated with test product submodule SM2 foundation;

The switch of C, closed resistance-switch series arm I, and the charging connecting valve opening test product submodule SM1 and SM2 DC terminal, make to form resonant tank between test product submodule SM1 and SM2 and load reactance device;

The fpga chip of D, microcontroller sends the pwm pulse unlock command of test product submodule SM1 and SM2, by the PWM pulsewidth width t in each cycle in microcontroller inquiry sine table, and determining pwm pulse rising edge and negative edge moment in each cycle by formula (10000-t)/2 and (10000+t)/2, in triggers test product submodule SM1 and SM2, each IGBT device turns on and off;

After E, test product submodule SM1 and SM2 internal receipt to the pwm pulse unlock command of microcontroller, order about IGBT and driven control is turned on and off to each IGBT device in test product submodule SM1 and SM2;

F, rising DC capacitor voltage make it reach rated voltage, and resonant tank enters steady state (SS);

G, by the electric current of each IGBT device in test product submodule SM1 and SM2 and magnitude of voltage, determine the loss of each IGBT device in test product submodule SM1 and SM2;

Described single module IGBT device testing experiment is tested separately each test product submodule, and single module IGBT device testing experiment comprises the test of overcurrent superpotential and the short-circuit current test of single module IGBT device; Perform following operation before the test:

I, load inductance is connected in parallel on the upper pipe IGBT device two ends of test product submodule, and keeps pipe IGBT device to be up and down in blocking;

II, direct supply are the direct current capacitors charging of single test product submodule;

The switch that III, disconnection are connected with direct supply;

IV, the pulse producer be connected is driven to produce pipe IGBT device conducting under monopulse or the single test product submodule of Two-pulse triggering by with single test product submodule IGBT;

V, measure pipe IGBT device under single test product submodule and turn off superpotential, excess current and di/dt protection value.

2. test method as claimed in claim 1, is characterized in that, in described step D, draws sine table according to the rising edge detected and negative edge:

5000×sin(2π×i/20+2π/20/2)+5000,i＝0,1,2…19 ①；

Wherein: i indicating impulse number, in one-period, 20 pwm pulses are had.

3. test method as claimed in claim 1, it is characterized in that, in described step G, in test product submodule SM1 and SM2, each IGBT device comprises on-state loss and switching loss; 2. and 3. the calculating of on-state loss and switching loss drawn by following formula:

Pcon＝Vce×Ic ②；

Psw＝fsw×(Eon+Eoff) ③；

Wherein: Pcon represents the on-state loss of IGBT device; Vce represents the instantaneous on-state voltage drop of IGBT device; Ic represents the instantaneous on state current flowing through IGBT device; Psw represents the switching loss of IGBT device; Fsw represents the switching frequency of IGBT device; Eon and Eoff represents that IGBT device turns on and off the energy in moment respectively.

4. test method as claimed in claim 1, is characterized in that, the overcurrent superpotential test of described IGBT device comprises the steps:

(1) calculate pulse producer export bi-pulse width and carry out actual test, described bi-pulse width t is expressed from the next:

④；

Wherein: Ic represents the maximum current value that needs reach; L represents load inductance value; U represents the maximum voltage value that needs apply;

(2) trigger pipe IGBT device under single test product submodule to open and turn off and produce excess current and superpotential;

(3) determine the loop stray inductance value Ls of single test product submodule, represent with following formula:

⑤；

Wherein: Us represents stray inductance induced voltage; The escalating rate of electric current I c when di/dt represents that lower pipe IGBT device is opened.

5. test method as claimed in claim 1, is characterized in that, the short-circuit current test of described IGBT device comprises the steps:

(1) pipe IGBT device on the single test product submodule of low self-induction wire short circuit is adopted;

(2) pulse producer produces monopulse, and single pulse width is by 4. formula calculating;

(3) pipe IGBT device make this pipe generation instantaneous short circuit under the single test product submodule of monopulse triggering and conducting, tolerance moment kA level electric current, makes pipe IGBT device under single test product submodule drive and starts di/dt protection instantaneously.