DE3409631A1 - Circuit arrangement for a power converter drive of a vehicle with DC voltage supply - Google Patents

Abstract

In this circuit arrangement, an asynchronous machine (ASM) which serves as a drive machine of an electrical power unit is fed via a DC chopper converter (TH, LK, CK, TL, LU, TU, DF, DB), an intermediate-circuit restrictor (Ld) and an inverted rectifier (WR). The braking moment which occurs during braking operation can be larger in size due to the omission of the field attenuation mode, than the moment occurring during travelling mode. In order to limit the increased intermediate-circuit voltage (Ud) occurring as a result during braking operation, a drop resistor (RV1) with parallel bypassing thyristor (TV1) is provided between the inverted rectifier (WR) and the brake diode (DB2) which serves for feedback. Since the drop resistor (RV1) is directly assigned to the DC chopper converter, the bypassing thyristor (TV1) can be turned off by the turning-off device which is present in any case for the main thyristor (TH) of the converter. <IMAGE>

Description

BROWN, BOVERI & CIE AKTIENGESELLSCHAFT

Mannheim March 14, 1984

Mp. No. 540/84 ZPT / P3-Pn / Bt 10

Circuit arrangement for a converter drive of a vehicle with direct voltage supply

The invention relates to a circuit arrangement for a converter drive of a vehicle
DC voltage feed according to the generic term of

Claim 1 and is particularly suitable for electric traction vehicles.

Such a circuit arrangement for a converter drive of a vehicle with DC voltage feed is from Elektro Bahnen, 79- year., 1981, issue 4,
Pages 110 to 116 known. There the drive machines (three-phase asynchronous machines) are via a
DC chopper and a DC link inverter.

Such a circuit arrangement is shown in FIG. A DC chopper GS is on the one hand with the first pole of a DC voltage source G (DC voltage Ue)> on the other hand connected via an intermediate circuit choke Ld to the first input of an inverter WR

(Intermediate circuit current 1 ^, intermediate circuit voltage Ud). Of the The second pole of the DC voltage source G is connected to the second input of the inverter via a travel brake contact FB INV connected. The first pole of the DC voltage source G is connected to the second via a braking diode DB1 Input of the inverter WR. The second pole of the DC voltage source is connected via a freewheeling diode DF the common connection point of DC chopper GS and DC link choke Ld connected. At the same The connection point is also a braking thyristor TB1, which on the other hand is connected to the second via a braking resistor RB1 Input of the inverter WR is connected.

As mentioned, the inverter WR is used to feed one or more asynchronous machines ^) ASM. To reduce the voltage stress of the inverter WR when braking the vehicle are between the inverter WR and the traction motor three-phase, with a switching device S bridged motor series resistors RVM arranged.

The motor series resistors RVM are necessary because in braking operation, in contrast to driving operation, a higher torque is required. Because the field weakening mode is no longer available in braking mode, the machine voltage is higher than when driving.

Since the intermediate circuit voltage (rectified machine voltage) Ud takes on higher values than the DC voltage Ue (mains voltage) would be without the motor series resistors RVM no stable braking operation possible. The motor series resistors RVM are used in the area of high braking performance switched on at high speeds and bridged at falling speeds.

From DE-OS 30 44 129 it is known to use the driving brake

contact FB of a DC chopper through a regrouped thyristor to replace. Thus, the three-phase switching device S is disadvantageously the only mechanical one Switching element that has to switch power during operation and is therefore exposed to increased wear is. It is possible to switch the three-phase switching device S through three antiparallel thyristor pairs to replace. However, the current load on the semiconductors would be relatively high because the Semiconductors not only have to carry electricity during braking, but also during the entire driving process. Since the occurrence a positive voltage at the thyristors is not exactly known, the earliest possible ignition point is available not fixed, the control would therefore have to be done with long pulses.

On this basis, the invention is based on the object of a circuit arrangement for a converter drive of a vehicle with DC voltage supply of the type mentioned at the beginning, in which the braking torque In terms of amount, it can be greater than when driving and the connection in a contactless and simple manner an additional resistor in braking mode.

This object is achieved by the features characterized in claim 1.

The advantages that can be achieved with the invention are in particular that only one series resistor and not three Series resistors as in the known case are necessary. There are lower material costs, a weight saving, a reduction in the cabling effort and a reduction in the installation volume. Furthermore, are omitted the switching noises previously occurring when the series resistors were switched on. The feed-in energy can depending on

Design around 20 to 30 $ compared to the known case increase. The high leveling process in the intermediate circuit current caused by the switching action up to now not applicable. Since the switching time is exactly known, a corresponding connection can be made.

Advantageous embodiments of the invention are characterized in the subclaims.

Embodiments of the invention are explained below with reference to the drawings.

Show it:

a first variant of a DC chopper with a directly assigned series resistor,

a second variant of a DC power converter with a directly assigned series resistor, an arrangement of the series resistor in any contactless two-quadrant converter circuit,

the possible feedback energy of the DC power converter,

7 the time courses of currents and voltages of interest in the first variant, 8 shows the time courses of currents and voltages of interest in the second variant.

In Figures 2 and 3, two variants are shown, which show how a with little circuit effort High speeds and torques additionally required series resistor directly assigned to the DC chopper can be.

In Fig. 2 is a first variant of a DC converter shown with a directly assigned series resistor. A DC voltage source G with a DC voltage Ug

Fig. 2 Fig. 3 Fig. 4th Fig. 5 Fig. 6th Fig. 8th

• «Γ '

is connected with its first pole via a main thyristor TH (RLT, thyristor with parallel-connected oppositely directed resonance diode) and a commutation choke LK with the intermediate circuit choke Ld of the direct current intermediate circuit. The second pole of the DC voltage source G lies above a regrouping thyristor TS (voltage at the thyristor: Uts, current through the thyristor: its) ^{at the} second pole of the direct current intermediate circuit. The regrouping thyristor TS is conductive when driving and blocked when braking. The intermediate circuit current flowing in the direct current intermediate circuit is denoted by Id.

A quenching thyristor TL for the main thyristor TH is connected on the one hand to the first pole of the DC voltage source G and on the other hand via a commutation capacitor CK to the connection point A between the commutation inductor LK and the intermediate circuit inductor Ld. The voltage across the capacitor CK is denoted by UcK »the current flowing through the capacitor is denoted by Iq ^ . The connection point of the quenching thyristor TL / capacitor CK is also connected to the connection point A.

The connection point Umschwingthyristor TU / Umschwingdrossel LU lies above a quenching diode DL for the regrouping thyristor TS, a bridging thyristor TV1 (voltage at the thyristor: Utvi »current through the thyristor: ITVi) ^{and (} * a current rise limiting choke LTV at the second pole of the DC link. LTV, the series connection of an auxiliary capacitor CV1 and a current rise limiting choke LCV is parallel. The voltage at the auxiliary capacitor CV1 is Ucvi » ^the current through the capacitor

tor designated with icV1. The auxiliary capacitor CVI lies a series resistor RV1 in parallel.

The common connection point of DL, TV1, CV1 and RV1 is via a braking diode DB2 (voltage at the diode:

^U DB2> current through the diode: iDB2 ^ ^{connected to the first Po1 of} the direct voltage source G. The connection point A is also connected to the second pole of the DC voltage source via a freewheeling diode DF. G connected. 10

The braking branch between the connection point A and the first pole of the DC voltage source G exists from the series connection of a braking thyristor TB2 and a braking resistor RB2, the braking resistor RB2 is subject to induction.

An inverter WR is connected to the poles of the direct current intermediate circuit, with a three-phase Asynchronous machine ASM is connected.

In Fig. 3, a second variant of a DC chopper is shown with an associated series resistor. the from the units G, TH (voltage at thyristor: UtH »current through the thyristor: ίχΗ), LK, Ld, WR, ASM, TS, RB2, TB2, TL, CK, LU and TU existing arrangement is as described under FIG. In contrast to the circuit 2 is a regrouping clear thyristor at the common connection point of LU and TU or CK and LU TLS (voltage at the thyristor: Utls »current through the thyristor: itls) connected, the other hand directly with is connected to the second pole of the DC link.

At the second pole of the DC link there is also a series resistor RV2 connected in parallel Bridging thyristor TV2 (voltage at the thyristor: U "pv2j

Current through the thyristor: iTV2) · This parallel connection is on the other hand via a current rise limiting choke Li1 with a braking diode DB3 (voltage on the diode: UdB3, current through the diode: 1DB3). 5

In Fig. 4 is an arrangement of the series resistor in any contactless two-quadrant converter circuit shown. The first pole of the DC voltage source G is via a main branch ZH and the Intermediate circuit choke Ld connected to the inverter WR (first pole of the direct current intermediate circuit). Of the The second pole of the DC voltage source G is located on a drive grouping branch ZS on the inverter WR (second pole of the DC link). The inverter WR in turn feeds the asynchronous machine ASM.

The second pole of the DC voltage source G is connected via a freewheeling branch ZF to the common connection point of the main branch ZH and the intermediate circuit choke Ld. closed. The first pole of the DC voltage source G is via a feedback branch ZR and a series resistor RV3 connected to the second pole of the DC link. The series circuit is connected to the series resistor RV3 a bypass thyristor TV3 with a current rise limiting reactor Li2 in parallel. Further an auxiliary capacitor CV2 can be connected in parallel to the series resistor RV3.

The circuit can optionally be equipped with a brake branch ZB1 or ZB2. The braking branch ZB1 is included parallel to the main branch ZH. As an alternative to this, the braking branch ZB2 is between the common connection point of the main branch ZH and the intermediate circuit choke Ld as well connected to the common connection point of the feedback branch ZR and series resistor RV3.

The free-running branch ZF and the Rüok feed branch ZR can consist of a diode or a controllable semiconductor (thyristor) and one in series with it Current rise limiting choke included. 5

The main branch ZH and the driving grouping branch ZS contain a controllable semiconductor with a quenching device. A current rise limiting choke can in turn be connected in series with the controllable semiconductor be. The controllable semiconductor can be a GTO (gate-turn-off thyristor) or a thyristor with a corresponding Be extinguishing device. The braking branch ZB consists of a thyristor and a thyristor arranged in series with it Braking resistor.

The mode of operation of the DC chopper circuit with regard to the ignition and extinction of the bypass thyristor TV1 is explained below with reference to FIGS. 6 and 7 for the variant according to FIG. In Figures 6 and 7, the time curves of the currents ΐχυ, * iTS, iTV1, iDB2 »iCV1» iCKi of the voltages Utu, Uts> ^Ü TV1> ^U DB2> ^U CV1 »UcK and the ignition pulses for TS, TU, TV1 and TH shown.

The initial state is that the DC chopper is in braking mode. The braking thyristor TB2 is conductive and the intermediate circuit current i (j would flow via LTV, TV1, DB2, RB2, TB2, Ld.

The voltage at the commutation capacitance CK is accordingly the polarity specified in Fig. 2 is positive.

The bypass thyristor TV is basically deleted in two main steps: In a first step, after TB2 and TH have been deleted, TS is ignited and TV1 is extinguished (period

4ή

to t3) · ^In a second step, TS is extinguished by igniting TU (period between t3 and

To carry out the first step, the main thyristor TH must first be ignited when the brake thyristor TB2 is conductive will.

The current commutates aperiodically from RB2, TB2 on TH, LK. A current flows through LTV, TV1, DB2, TH, LK, Ld. The ignition of the main thyristor TH This is followed by the ignition of the reversing thyristor TU, which also results in a current flow via CK, LU and TU. Towards the end of the capacitor voltage oscillation, the quenching half-oscillation is activated by the firing of the quenching thyristor TL initiated.

After the quenching half-oscillation, the time-linear charge reversal via LTV, TV1, DB2, TL, CK, Ld follows. As soon the voltage at CK has reached the input voltage Ue, starts commutation from TL, CK to Ue> DF, i.e. TL goes out and there is a current flow via LTV, TV1, DB2, G, DF, Ld.

After a minimum time after the quenching half-oscillation, the regrouped thyristor TS is triggered at time ti. The intermediate circuit current i ^ commutates from DB to TS. In addition, there is a current flow via CV1. This commutation is completed at time t2. In the period between t £ and t% there are current flows via WR, TS, DF, Ld and via LTV, TV1, CV1, LCV.

At the point in time t%, the electricity in TV goes out. Until the reversing thyristor TU ignites at time tjj, the voltage across the auxiliary capacitance CV1 can decay exponentially, ie there is a current flow through CV1 and

. RV1.

The reversal caused by the ignition of TU commutation capacitor voltage (current via LU, TU, CK), which ends at time t5, commutation closes from DF, TS to LCV, CV1, RV1, DL, LU, CK. this commutation process is ended at time to.

From the time t3 on, the thyristor TS is loaded in the reverse direction. At the same time, the linear charge reversal of the commutation capacitance CK begins. The current flow is LCV, CV, RV1, DL, LU, CK, Ld.

The closed time of the regrouping thyristor TS ends at time tj. The linear charge reversal from CK continues until the main thyristor TH is triggered at time tg.

The main thyristor TH is only ignited when it is sufficiently high to cancel the intermediate circuit current Voltage at CK is reached (this requirement is met at time t8). There are current flows over LCV, CV1, RV1, DB2, TH, LK, Ld and DL, LU, CK. From time t8, the actuator works again in braking mode.

At time tg, the commutation of CK, LU, DL is on DB2, TH, LK ended. The current flow is LCV, RV1, DB2, TH, LK, Ld.

At time t-jq (see Fig. 7), the bypass thyristor becomes TV1 ignited. The damping of the parallel resonant circuit RV1, CV1, LCV and LTV is such that the Current 1TV1 at time tu cannot become zero. It this results in a commutation from LCV, RV1 to LTV, TV1.

The mode of operation of the second variant of the DC chopper circuit according to FIG. 3 is described below the deletion of the bypass thyristor TV2 is explained with reference to FIG.

8 shows the time curves of the currents iTÜ> iTLS »iTV2, iDB3, iCK, the voltages ÜTH> ^Ü TLS, UTV2, ÜDB3, ^U CK and the ignition pulses for TU, TLS, TH and TL.

The initial state is the same as in variant 1. The braking thyristor TB2 is conductive and the intermediate circuit current I _d flows via TV2, Li1, DB3, RB2, TB2 and Ld. The voltage at CK is positive as defined in FIG.

After the DC chopper has been extinguished by triggering the corresponding thyristors (TH, TU, TL, see Variant 1) the intermediate circuit current I ^ flows via TV2, Li1, DB3, G, DF and Ld.

At time t-j, the reversing thyristor TU and

the regrouping quenching thyristor TLS ignited. The intermediate

Circulating current I ^ commutates from TV2, Li1, DB3, G, DF and on TU, TLS.

At the same time, the oscillation current iCK of the commutation half-oscillation is superimposed on the current in TU. 30th

At time t2, the current in DB3 and TV2 goes out.

The commutation capacitor voltage swing ends _{at time t 3.} At this point in time, the current Id flows into TU and TLS

The commutation capacitor voltage tries to swing back via the still current-carrying thyristor TU and causes the current in TU to be extinguished at time t4.

From the point in time ti \ , the commutation capacity is reloaded linearly via TLS, LU, CK. Until the capacitor voltage Uck crosses zero, at time t $, DB3 is loaded in the reverse direction.

The main thyristor TH is triggered at the instant t3. The intermediate circuit current commutates from TLS, LU, CK to RV2, LiI, DB3, TH, LK.

The commutation is ended at time tj , and the closed time tsLS begins for the thyristor TLS. Before the next deletion is initiated by ignition of TU, a period of time necessary to wait, which is as long at least as the required recovery time TSLS ^it d thyristor TLS.

In all the circuit examples, the additional series resistor RVl, 2, 3 is used by the bridging thyristor TV1,2,3 shorted. The bridging thyristor is always deleted by the one for the main thyristor TH existing extinguishing device.

In the variant according to FIG. 2, the auxiliary capacitor CV1 ensures an increase in the closed season of TS, where dimension and weight of the capacitor CV1 and the choke LCV compared to the conventional switching device S low are.

In the variant according to FIG. 3, the additional capacitance CV1 can be omitted. The quenching diode DL according to the variant However, Fig. 2 is to be replaced by the additional thyristor TLS, otherwise the entire equation

JS-

power controller must be designed for a voltage Ue + Id * ^RV .

An arrangement of the additional series resistor RV, which can be bridged with a thyristor TV, can be used any contactless two-quadrant converter circuit consisting of 4 or 5 converter branches, realize, as Fig. 4 shows.

In all cases there is the possibility of using the periodic Ignition and extinction of the bypass thyristor TV1, TV2, TV3 shown in hatched lines in FIG Energy that is converted into heat in the conventional arrangement in the RVM motor series resistors.

to feed back. The possible feedback energy (braking power / 'PBR ^dt ) increases by 20 to 30%.

5 shows the intermediate circuit current Id, the intermediate circuit voltage Ud and the braking power PßR i- ^{n as a} function of the driving speed V of the vehicle. The intermediate circuit current remains constant at its nominal value IdN regardless of the driving speed.The intermediate circuit voltage Ud increases from a value ^ü R0 (= sum of all voltages at V = 0km / h) to a value Udmax (= sum of all voltages at ν = Vmax) ^at maximum Speed. The voltage at the additional series resistors RV1,2,3 is designated Urv = 2RVM · Id.

DC chopper circuits which have the above-mentioned arrangement of an additional series resistor RV and bridging thyristor TV can also be built with GTO's (GTO = Gate turn off thyristor).

Claims (6)

Expectations Circuit arrangement for an asynchronous machine of a vehicle fed from a DC voltage source via a DC chopper, an intermediate circuit choke and an inverter, with a driving grouping branch, a freewheeling branch and a braking branch, characterized in that the braking branch (DB2,3, ZR) has a series resistor assigned directly to the direct current chopper (RVl, 2,3) is connected to the inverter (WR) with a bridging thyristor (TV1,2,3) connected in parallel. 2. Circuit arrangement according to claim 1, characterized characterized in that the bridging thyristor (TV1,2,3) a current rise limiting choke (LTV, Li1, Li2) in Row lies. 3. Circuit arrangement according to one of claims to 2, characterized in that the series resistor (RV1,3) an auxiliary capacitor (CV1,2) is parallel. 4. Circuit arrangement according to claim 3, characterized in that to the series resistor (RV1) and Auxiliary capacitor (CV1) in parallel with a current rise limiting choke (LCV) in series lies. 5. Circuit arrangement according to one of claims to 4, characterized in that the inverter (WR) remote connection of the bridging thyristor (TV1) via a quenching diode (DL) with the quenching device of the sliding current controller is connected. 6. Circuit arrangement according to one of claims ¹ to 1, characterized in that the terminal of the bridging thyristor (TV2) connected to the inverter (WR) is connected to the quenching device of the DC chopper via a regrouping quenching thyristor (TLS).