DE2743927A1 - REGULATED ELECTRONICALLY COMMUTED DC MOTOR - Google Patents

Description

SIEMENS AKTIENGESELLSCHAFT Our mark

Berlin and Munich 77 P 3 2 5t FRG

- 3-

Regulated electronically commutated direct current motor

The invention relates to a regulated electronically commutated direct current motor, with a permanent magnet rotor and stator windings connected in star or ring, which can be switched to a DC voltage source via commutation transistors are, the commutation transistors by one of a rotor position sensor influenced selection circuit are confessed, in which motor also a free-wheeling circuit for the stator windings and one through which the operating and freewheeling current flows, the actual value for a motor current regulator designed as a two-point regulator delivering current measuring resistor as well as one of one Braking current regulator controlled braking resistor element to limit the brenis current are provided.

A DC motor of this type from DT-PS 22 37 870 known become. In this known motor are between the commutation transistors and a transistor controlled cyclically by the current regulator, a further measuring resistor for the braking current and another transistor arranged as a controllable braking resistor element, which in normal operation by a Switching element are bridged. In normal operation, the control transistor cyclically controlled by the current regulator and thus regulates the speed of the motor. When switching to braking mode the switching element is opened and the current driven by the EMF of the motor must pass through the further measuring resistor, the further The transistor, the smoothing choke and the freewheeling diode flow.

909828 / OOOS

27.9.1977 / Hs 2 nit

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In braking operation, the further transistor is then limited to a permissible value by the braking current regulator.

The invention has for its object to simplify a DC motor of the type mentioned in that for the Braking current limitation practically only requires a braking current controller will. According to the invention, this object is achieved in that at least a part of the Commutation transistors is used. The braking current regulator and the motor current regulator are preferably obtained from a common one Current measuring resistor its actual value, whereby the setpoint for the braking current controller is higher than the setpoint for the motor current controller. Compared to the known motor, the further transistor serving as a controllable braking resistor element can be used and the additional measuring resistor for the braking current controller can be saved. Furthermore, the use of the commutation transistors as a braking resistor element compared to the known motor still has the advantage that the power loss in braking operation divided between several transistors, since each stator winding only carries current over a certain angle.

The invention can be used with particular advantage in an electrically commutated direct current motor in which the Stator windings via a bridge circuit made of commutation

"" 5 transistors can be connected to the DC voltage source, namely in such a way that the commutation transistors of one half of the bridge are the motor current regulator and the commutation transistors the other half of the bridge are assigned to the braking current controller. The commutation transistors assigned to the braking current regulator work here in active operation.

Based on the drawing, in which two exemplary embodiments are shown are, the invention is explained in more detail. Show it

Figure 1 shows an electronically commutated direct current motor, in which the stator windings via a bridge circuit from commutation transistors can be placed on the DC voltage source and

Figure 2 shows an electronically controlled direct current motor, with a controller output stage.

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With W1 to W4 the star-connected ones are spatially at 90 ° Stator windings that are offset from one another and that have their free winding connections on the one hand via commutation transistors V1 to V4 of one half of the bridge with the positive pole of a DC voltage source Ug and on the other hand via commutation transistors V5 to VB of the other half of the bridge and a current measuring resistor R1 are connected to the negative pole of the DC voltage source. In series with the commutation transistors V5 to V8 are arranged in the forward direction connected diodes V9 to V12. Also with the free Ends of the stator windings or the connection points of the commutation transistors V1 to V4 or V5 to V8 freewheeling devices V14 to V17 are provided, which are common to their other terminal pole are connected to the negative pole of the DC voltage source Ug. The commutation transistors V1 to V4 of one half of the bridge are via a preamplifier W1 and the commutation transistors V5 to V8 of the other bridge halves via a preamplifier W2 activated. The two preamplifiers W1 and W2 receive their commutation signals from a selection circuit AW depending on a rotor position transmitter not shown in the drawing. Via an input so-called M. can be a signal to change the torque direction, in which case the control cycle of the commutation transistors V1 until V8 is changed accordingly.

A current regulator SR is also provided, which clocks the commutation transistors V1 to V4 via the preamplifier W1. The current regulator SR is thus designed as a two-point _{regulator which receives its actual value I is} + from the current measuring resistor R1; the setpoint value I _{soll is} specified for the current regulator SR via another input. A braking current regulator BSR is also provided, which acts on the preamplifier W2 of the commutation transistors V5 to V8 via a transistor V13. The braking current regulator BSR also receives its current actual _{value I ist} »from the current measuring resistor R1 while the setpoint I ^B _{S (} oi is specified via another input. IB 3 is set about 10% higher than the setpoint I so that the braking current regulator does not respond during normal operation ₃₀ Ti of the current controller SR.

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In normal operation, the commutation transistors V1 to V8 are controlled cyclically, namely in the sequence V1 + V7, V2 + V8, V3 + V5, V4 + V6. Since the stator windings W1 to W4 are offset from one another by 90 °, ie the winding axes of the stator windings W1 and W3 or W2 and W4 are directed towards one another, the two transistors that are cyclically controlled over 90 ° generate transistors for the winding pairs W1 and W3 or W2 and WA is a rectified field vector. If, for example, the two commutation transistors V1 and V7 are controlled by the selection circuit AW, a current flows from + Ug via commutation transistor V1, stator winding W1, stator winding W3, commutation transistor V7 and current measuring resistor R1 to Ug. _{If the motor current I lst reaches} the setpoint value ¹ SOlI 'during this cycle, the current ^{regulator SR causes the} commutation transistor V1 to close via the preamplifier W1, while the commutation transistor V7 remains open. A compensating current can thus flow from the stator windings W1 and W3 via the commutation transistor V7, current measuring resistor R1 and freewheeling diode V14 back to the stator winding W1. The current measuring resistor R1 also detects the freewheeling current. When switching to braking mode, a braking signal is triggered in a manner known per se via a speed controller not shown in the drawing, the input so-called M receiving a corresponding signal which, via the selection circuit AW, causes the current direction in the windings W1 and W3 to pass Activation of the commutation transistors V3 and V9 is reversed if the two commutation transistors V1 and V7 were still activated at this point in time . As a result, the current I _18t rises above the setpoint I _ao n of the current regulator SR, so that the latter immediately closes the commutation transistor V3 again. The energies stored in the stator windings W1 and W3 drive a demagnetization current from the stator winding W3 via the diode path of the commutation transistor V3 (since in the present case so-called Darling transistors are used) + Ug, via the battery to -Ug, freewheeling diode V14 and stator winding W1. However, as soon as the demagnetization has subsided, the permanent magnet rotor in

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the stator windings of the induced EMF M _o tors driven, a current flows from the stator windings W3 and W1 on Kommutierungstransistor V5, current measuring resistor R1, freewheeling diode V16 back to the stator winding W3. The height of this current

I _K = _{> where Uel covers all} threshold values of the diodes and transistors in the circuit and RW is the winding resistance. This current Ij, can therefore be very high and is usually considerably greater than the normal starting current. If the motor current I _R now reaches the setpoint ^IB _S0 ; n of the braking current controller BSR, the commutation transistors V5 to V8 are controlled via the transistor V13 and the preamplifier W2 so that the braking current does not exceed its setpoint ^ IB ,,. The commutation transistors V5 to V8 are therefore operated in the active range during braking operation and thus limit the braking current. Since the braking current is set approx. 10% higher than the starting current, it is avoided that the braking current controller B3R is engaged during startup. As soon as the braking current has decayed to such an extent that the value ^{falls below the setpoint 1} O ₀₁₁ , the current regulator SR comes into action again.

In the exemplary embodiment according to FIG. 2, the same reference numerals are used for parts that are functionally identical as in the exemplary embodiment according to Figure 1. The commutation transistors V1 to V4 are replaced by one in this exemplary embodiment Controller output stage V18 and this is via the preamplifier VV1 driven by the selection circuit AW. The commutation transistors V5 to V8 are in a corresponding manner via the preamplifier W2 Way controlled by the selection circuit AW. In addition, the preamplifier W2 is from the braking current regulator via the transistor V13 BSR influenced. The current regulator SR influences a regulator output stage V18 via the preamplifier W1. The current regulator is again designed as a two-position controller and clocks the controller output stage V18 via the preamplifier W1. With the star point of the windings W1 to W4 is the cathode of a freewheeling diode V19 while the anode is connected to -Ug of the voltage source.

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In normal operation, the stator windings W1 to W4 are controlled cyclically by the selection circuit AW via the commutation transistors V5 to V8 and preamplifier W2. The actual motor current value! "". Ι- is taken from the current measuring resistor R1 and fed to the current regulator SR and the braking current regulator BSR. The current regulator SR works clocked and controls the regulator output stage V18 via the preamplifier W1. If the setpoint I _{soll of} the current controller SR is reached, the controller output stage V18 interrupts the circuit. The current flow from the respective winding W1 to W4 can therefore be maintained via the respective activated commutation transistor V5 to V8. When the controller output stage V18 is blocked, this current flows, for example, from the stator winding W1 that has just been activated, via the commutation transistor V5, the current measuring resistor R1 and the free-wheeling diode V19 back to the stator winding W1. In braking mode, the commutation sequence of the commutation transistor V5 - V8 is changed by a corresponding signal at the input so called M of the selection circuit AW via preamplifier W2 and a current of such a magnitude then flows through the current measuring resistor R1 that the current regulator SR closes and the regulator output stage V18 blocks . The current driven by the EMF of the motor also flows through the current measuring resistor R1 and freewheeling diode V19. As soon as this current reaches the setpoint IB _{goll of} the current brake controller BSR, a control signal for the current is sent via transistor V13 and preamplifier W2.

! 5 limitation of the respective commutating transistor. Also in In this case, the commutation transistors V5 to V8 are driven in the active area and thus limit the braking current.

5 claims 2 J ^ figures

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Claims (1)

- ^ - V P 3 I \) 1 FRG Pate nt claims (1. Regulated electronically , the commutation currents.i are controlled by a selection circuit influenced by a rotor toi lungsgeber, in which motor also a free-wheeling circuit for the stator windings and a from the operating and free-wheeling current throughf, the Γ stromreg * he donating Strorameßwiderstand and a are vf'rgesehen of einom Bremssti omr-EGJ he · ■ <(· 'st-eu "rt.es Bremswiderstandaelement to Bremsstronibegrenzuiig, d ei d urchgeke η η ζ c o r η -. ■ t, <λ · Μ \ a ^ Lk iireta resistance element at least one phr advised ^KommulU! Hmgst ^r 'orisistoren (V5 to V8) v ^ rwendot is, 2. DC motor according to claim 1, dn'hTc.h germinated Lehnet, that the motor current controller (SR) and the Bremsstvonn eg! «r (BSR) from a common current measuring resistor (H1) to your Xstvert obtained, where the setpoint for the Bt i-MiisatroKirf-'glei- fBSFt) is higher than the setpoint value for the motor t romreg J er · (f, R). 3. Gleif-hstrommotor according to claim 1 or> r '■>, in which the stator winding via a Brokenr-chal device from commutation,' -! Transistors can be connected to the DC voltage source, characterized in that the commutation resistors : (Vl to Wt) of one half of the bridge d «? M motor flow ref5lf » r ι'Wl) 'uid the coordination disruptions (Vb bi ί Ve) in the other half of the bridge are assigned to the burner current regulator (BSR) (KIg ., 1). 'f. Gleichstroifimotor bi after an I dei ¹ Ansprüclie 1;>*>, characterized in that the dom Bremsstromi egler (Bf [:) associated Komr: iutierungr> tr msistor "n (V ^r> work up VH) in braking operation in active mode.? . 909828/0005 BATH ORIGINAL - * - 77 P 3 2 5! FRG 5. DC motor according to ein§m of claims 1 to 4, characterized characterized in that the control of the braking current limitation serving commutation transistors (V5 to V8) via a Transistor (V13) from the braking current regulator (BSR) takes place. 909828/0005