Electronic controllable (phase) compound excitation regulator
The utility model is the field regulator of a kind of control synchronous generator (compensator), belongs to the power system automation technology field.
The existing field regulator that adopts (phase) compound excitation current source all is electromagnetic type controlled (phase) compound excitation adjuster, and its shortcoming is to use electromagnetic components such as magnetic amplifier, reactor more.The electromagnetic component complex structure, tap is many, unstable properties, debugging inconvenience, operating rate is slow simultaneously.This adjuster is that the employing three phase mains is arranged mostly, so enough electric currents of encouraging by force can not be provided under some short circuit condition, need install relay again additional and encourage device by force, and the loop does not have reliable standby measure yet.Existing is the electronic type field regulator in exciting power source with the set end voltage source, all adopting controllable silicon is power control member, need many group (3 or 6 groups) synchronous trigger circuits, the circuit more complicated, again owing to will guarantee under the situation that set end voltage descends, still can provide enough encouraging by force,, increase the volume and the cost of device so the nargin of each element of exciting power loop is bigger.
The purpose of this utility model is at the deficiencies in the prior art, and a kind of enough power, electronic type controlled (phase) compound excitation field regulators that power control is simple, with low cost of encouraging by force that all can provide under the various faults of system are provided.
The utility model is by voltage measurement and tuning device (B
3), group amplifier (B
5), pulse width controller (B
6) form they and the voltage transformer pt summation current transformer CT formation closed loop excitation automatic control system of exciter (or not having exciter), generator with controlled (mutually) compound excitation circuit.Controlled (phase) compound excitation circuit is by PT and CT, the current limliting capacitive reactance (C of generator
A, C
B, C
C), compound excitation transformer (KXB), bridge rectifier (SQL) and power transistor chopper (T in parallel
1, T
2) form.In this circuit, the voltage and the next electric current of CT that are come by PT have formed (phase) compound excitation current source, power transistor chopper in parallel and capacitance-resistance absorption circuit (R, C) thereof then constitute a dynamic shunt circuit, output after the shunting is exactly the output of this adjuster, the size of its output variable is to realize recently that by the duty of control power transistor shunt chopper on-off mode work is adopted in transistorized work.Simplification as the dynamic shunt circuit, transistor also can adopt the method for static splitting, even transistor works in the amplification mode, shunting will be controlled by the size of transistor base current, this moment, the pipe consumption was bigger, therefore only was applicable on the less unit below 10000 kilowatts.In order to improve reliability, the voltage tuning device adopts resolver, also available selsyn.In order to reduce interference, the signal of pulse width controller is by the base stage of photoelectrical coupler oxide-semiconductor control transistors.Cross the work of flow restriction utilization restriction closed loop, looking in the time of can avoiding limit movement hunted phenomenon.
The utility model adopts three-phase (phase) compound excitation circuit, and the enough power of encouraging by force all can be provided under the various faults of system, and power control is very simple, only with a power transistor, has that circuit structure is simple, volume is little, low cost and other advantages.
Accompanying drawing is a circuit theory schematic diagram of the present utility model.
The utility model can be realized by scheme shown in the drawings, the core of electronic type controlled (phase) compound excitation circuit is power transistor shunt chopper (or static splitting circuit), corresponding to generator certain voltage and electric current, it is corresponding with it that (phase) compound excitation rectification circuit just provides a constant current.But the electric current I of adjuster output
TThen should require to regulate automatically, and the two equates according to motor.Therefore need a controlled shunt circuit.The transistor T that shunt circuit is connected by Darlington
1And T
2(or high-power MOS tube) and resistance capacitance absorption circuit thereof, controllable silicon overvoltage protection and uninterrupted diverter switch (KK) and contactor (J) constitute.Shunt circuit can adopt the method for static splitting and dynamic shunt.Static splitting is fairly simple, and it makes circuit working at magnifying state.When at T
1Base stage adds certain electric current I
B1After, T
2Will flow through shunt current I
S=β
1β
2I
B1, β
1And β
2Be respectively transistor T
1And T
2Common-emitter current gain.Adopt this mode to work, because of T
2On bigger power consumption is arranged, so only be applicable to the occasion of less (for example below 10000 kilowatts) power.Dynamic shunt works on off state, transistor T
1Base current I
B1Be not a t continually varying amount in time, but one there are some cycles (T) and adjustable wide spike train (as shown in FIG.), under the control of this spike train, make shunt circuit be on off state.Work as I
B1Be timing, shunt current passes through transistor T
2Work as I
B1When negative, transistor T
1And T
2Be in OFF state, shunt current is by being connected in parallel on T
2On the capacitance-resistance absorption circuit capacitor C is charged.The size of shunt current is by changing I
B1The duty of spike train is recently realized.The resistance R of absorption circuit should be slightly less than the load resistance of adjuster, and capacitor C should be enough big, but the time constant of absorption circuit is more preferably greater than 1/2 chopping cycle (T), and the ability of enough withstand voltage and anti-pulse currents should be arranged.In order to guarantee the reliably working of adjuster, the power capacity of this resistance R should be enough big, and heat radiation will be convenient in its installation site.The break-make that shunt chopper does not stop makes its both end voltage become a row pulse wave towards ripple, and this impulse wave passes to current limliting capacitive reactance (C by (phase) compound excitation transformer (KXB) always
A, C
B, C
C) on, will the electric current by the current limliting capacitive reactance be changed significantly according to chopping frequency, and then influence the waveform of voltage transformer pt output voltage.In order to prevent this situation, the design of (phase) compound excitation transformer should strengthen former, secondary leakage reactance, and this can adopt on former, the secondary last hypomere that is placed on iron core column respectively, perhaps adds the space between former, secondary, also can adopt the method for additional reactance to realize.(phase) compound excitation transformer is set saturation value according to the restriction field-forcing voltage.The dc terminal of (phase) compound excitation rectifier is if open a way LC series circuit of reactance formation of current limliting capacitive reactance and (mutually) compound excitation transformer.This will cause dangerous overvoltage in the dc terminal of rectification circuit, should take measures to avoid.Diverter switch (KK) should make the phenomenon that does not all produce the output loop open circuit in any handoff procedure for this reason.The open circuit of shunt chopper and short circuit fail safe also are very important; controllable silicon TH and overvoltage trigger the loop as open failure protection usefulness; photoelectrical coupler G then sends the usefulness of switching signal for TH action back switching circuit, also being short-circuited as shunt chopper provided the usefulness of switching signal when losing efficacy.Stabilized voltage power supply (B
1, B
2) output ± 15V ,+10V and-the 3V direct voltage, reactive power measurement circuit (A
1), cross flow restriction and commutation circuit (B
4), uneven testing circuit (B
7) all can adopt conventional existing techniques in realizing.Field rheostat (RC) can be taked the universal product.Test resistance (R
T) power capacity determine according to generator capacity.