A controllable phase shifter device and control method thereof

Abstract

The present invention discloses a controllable phase shifter device, comprising a plurality of controllable windings connected in series, wherein the controllable windings include a transformer secondary winding, a damping circuit, and a full-bridge circuit; one end of the transformer secondary winding is connected to the input end of the damping circuit, and the output end of the damping circuit and the other end of the transformer secondary winding are connected to the input end of the full-bridge circuit; or the two ends of the transformer secondary winding are respectively connected to the input ends of two damping circuits, and the output ends of the two damping circuits are connected to the input end of the full-bridge circuit; the output ends of the plurality of full-bridge circuits are sequentially connected in series. The control method of the present invention realizes the conduction / disconnection of different bridge arms in the full-bridge circuit by closing / closing the switch in the damping circuit, thereby completing the adjustment of the controllable winding. The present invention can improve the transformer excitation inrush current suppression capability and reduce the winding short-circuit current by connecting an impedance in series to the winding.

Description

Technical Field

[0001] The present invention relates to a phase shifter device, and in particular to a controllable phase shifter device and a control method thereof. Background Art

[0002] Phase shifters are an effective means of controlling power transmission flow. They are installed in series in the line and change the voltage amplitude at the installation point or the phase difference between the voltages at both ends of the transmission line by injecting a compensation voltage into the line, thereby controlling the steady-state power flow of the line, achieving reasonable distribution of line transmission power, improving the efficiency of the transmission channel, and improving the cross-section transmission capacity. Conventional phase shifters all use mechanical voltage regulation. With the development of power electronics technology, the application of power electronic devices such as thyristors in phase shifter control has also been studied. Phase shifters that use power electronic devices such as thyristors for voltage regulation are called controllable phase shifters, which have the advantages of frequent operation, fast control response speed, and the ability to meet the needs of rapid control of power systems. The step-by-step switching controllable phase shifter uses power electronic devices as switches to switch the phase shifter excitation winding to control the voltage in series in the transmission line. It has the advantages of simple control and no harmonics. However, since the transformer winding is switched during the control process instead of continuous and smooth control, the transformer will cause excitation inrush current due to sudden changes in winding voltage. The excitation inrush current will have a certain impact on the control progress, control time and transmission system of the step-by-step switching controllable phase shifter. Summary of the invention

[0003] Purpose of the invention: The purpose of the present invention is to provide a controllable phase shifter device and a control method thereof which can suppress the excitation surge current in the adjustment process of the graded switching controllable phase shifter and reduce the influence of the excitation surge current on the system.

[0004] Technical solution: The controllable phase shifter device of the present invention comprises a plurality of controllable windings connected in series, wherein the controllable windings comprise a transformer secondary winding, a damping circuit and a full-bridge circuit;

[0005] One end of the transformer secondary winding is connected to the input end of the damping circuit, and the output end of the damping circuit and the other end of the transformer secondary winding are respectively connected to the input end of the full-bridge circuit; or the two ends of the transformer secondary winding are respectively connected to the input end of a damping circuit, and the output ends of the two damping circuits are connected to the input end of the full-bridge circuit;

[0006] The output ends of the three full-bridge circuits are connected in series in sequence.

[0007] Furthermore, the damping loop is composed of an impedance and a switch in parallel, and the impedance is a resistor, or an inductor, or a resistor and an inductor in series, or a resistor and an inductor in parallel.

[0008] Furthermore, the switch is a mechanical switch or a power electronic switch.

[0009] Furthermore, the full-bridge circuit is composed of four bridge arms, and each bridge arm is composed of a plurality of anti-parallel thyristors.

[0010] The control method of the present invention is implemented as follows: when any controllable winding is operating normally, the switch in the damping circuit is in a closed state, and the impedance in the damping circuit is bypassed;

[0011] When the first bridge arm and the third bridge arm are turned on, or the second bridge arm and the fourth bridge arm are turned on, the output voltage of the full-bridge circuit is zero;

[0012] When the first bridge arm and the fourth bridge arm are turned on, the output voltage of the full-bridge circuit is in phase with the transformer winding voltage;

[0013] When the second bridge arm and the third bridge arm are turned on, the output voltage of the full-bridge circuit is in opposite phase to the transformer winding voltage;

[0014] When two bridge arms are turned on and the other two bridge arms are turned off, the other two bridge arms need to be turned on. The adjustment steps are as follows:

[0015] S1, open the switch in the damping circuit and input impedance;

[0016] S2, locks the two bridge arms that have been turned on;

[0017] S3, after the current of the two bridge arms that have been turned on passes through zero and is turned off, the other two bridge arms that need to be turned on are triggered to be turned on;

[0018] S4, close the switch in the damping circuit to complete the conduction of the other two bridge arms;

[0019] For the adjustment of turning on or off any two bridge arms, repeat steps S1-S4;

[0020] Furthermore, when any of the controllable windings needs to be adjusted, the steps S1 to S4 are performed; for the controllable windings that do not need to be adjusted, the original conducting bridge arm is maintained.

[0021] Compared with the prior art, the present invention has the following significant effects: 1. The present invention connects an impedance in series with the winding to increase the transformer excitation surge current suppression capability during the controllable phase shifter adjustment process; 2. Because the impedance is connected in series with the winding, if the winding short-circuit occurs, the winding short-circuit current is reduced during the adjustment process of the controllable phase shifter, thereby improving the equipment safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic structural diagram of a first controllable phase shifter device of the present invention;

[0023] Figure 2 It is a schematic structural diagram of a controllable winding of a first controllable phase shifter of the present invention;

[0024] Figure 3 is a schematic structural diagram of a second controllable phase shifter device of the present invention;

[0025] Figure 4 It is a schematic structural diagram of a controllable winding of a second controllable phase shifter of the present invention. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0027] Figure 1 The first controllable phase shifter device provided by the present invention comprises three controllable windings (W1, W2, W3), the controllable windings are composed of Figure 2 The transformer secondary winding 1, the first damping circuit 2, and the full-bridge circuit 4 are composed of the transformer secondary winding 1. One end of the transformer secondary winding 1 is connected to the input end of the damping circuit 2, the output end of the damping circuit 2 is connected to the input end of the full-bridge circuit, and the other end of the transformer secondary winding 1 is connected to the other end of the full-bridge circuit. The damping circuit 2 is composed of a resistor 22 and a switch 21 in parallel. The full-bridge circuit 4 is composed of four bridge arms, each of which is composed of a multi-stage anti-parallel thyristor (41, 42, 43, 44) connected in series. The output ends of the full-bridge circuit 4 in the three controllable windings are connected in series in sequence to form a controllable phase shifter control winding structure.

[0028] Figure 3 The second controllable phase shifter device provided by the present invention comprises three controllable windings (W1, W2, W3), the controllable windings are composed of Figure 4 The transformer secondary winding 1, the first damping loop 2, the second damping loop 3, and the full-bridge circuit 4 are composed. The two ends of the transformer secondary winding 1 are connected to the input ends of the damping loop 2 and the damping loop 3 respectively, and the output ends of the first damping loop 2 and the second damping loop 3 are connected to the input end of the full-bridge circuit 4 respectively. The first damping loop 2 (the second damping loop 3 has the same structure as the first damping loop 2) is composed of a resistor 22 and a switch 21 in parallel. The full-bridge circuit 4 is composed of four bridge arms, namely the first bridge arm 41, the second bridge arm 42, the third bridge arm 43 and the fourth bridge arm 44, each bridge arm is composed of a multi-stage anti-parallel thyristor connected in series. The output ends of the full-bridge circuit 4 in the three controllable windings are connected in series in sequence to form a controllable phase shifter control winding device.

[0029] The control process of the controllable phase shifter device of the present invention is as follows:

[0030] like Figure 2 , for a single controllable phase shifter control winding structure, during normal operation, the switch 21 in the damping loop 2 is in the closed position, bypassing the impedance 22 in the damping loop 2;

[0031] When the first bridge arm 41 and the third bridge arm 43 are turned on, or the second bridge arm 42 and the fourth bridge arm 44 are turned on, the output voltage of the full-bridge circuit is zero;

[0032] When the first bridge arm 41 and the fourth bridge arm 44 are turned on, the output voltage of the full-bridge circuit is in phase with the transformer winding voltage;

[0033] When the second bridge arm 42 and the third bridge arm 43 are turned on, the output voltage of the full-bridge circuit is in opposite phase to the transformer winding voltage;

[0034] Each bridge arm is composed of anti-parallel thyristors, which are turned on in turn in the positive and negative half-waves of the current. When adjustment is required, if the original bridge arms are the first bridge arm 41 and the third bridge arm 43, and now the first bridge arm 41 and the fourth bridge arm 44 need to be turned on, firstly, the switch 21 of the damping loop 2 is separated, the impedance 22 is put in, and then the first bridge arm 41 and the third bridge arm 43 are locked, and after the current of the first bridge arm 41 and the third bridge arm 43 is turned off after zero crossing, the first bridge arm 41 and the fourth bridge arm 44 are triggered to turn on, and finally the switch 21 of the damping loop is closed.

[0035] When the second bridge arm 42 and the fourth bridge arm 44 are turned on, it is necessary to adjust the second bridge arm 42 and the third bridge arm 43 to be turned on. The adjustment steps are as follows:

[0036] S21, open the switch in the damping circuit and input impedance;

[0037] S22, locking the second bridge arm 42 and the fourth bridge arm 44;

[0038] S23, after the currents in the second bridge arm 42 and the fourth bridge arm 44 are turned off by crossing zero, the second bridge arm 42 and the third bridge arm 43 are triggered to turn on;

[0039] S24, closing the switch in the damping circuit to complete the conduction of the second bridge arm 42 and the third bridge arm 43;

[0040] Similarly, steps S21-S24 are used to adjust the conduction or shutdown of any two bridge arms. When both ends of the transformer secondary winding 1 are connected to the damping circuit 2, in step S21, the switches in the two damping circuits 2 are opened and the impedances are respectively put into operation; in step S24, the switches in the two damping circuits 2 are respectively closed.

[0041] Due to the existence of the impedance 22 in the damping circuit 2, the excitation surge current problem during the switching process of the transformer winding can be suppressed; at the same time, if the first bridge arm 41 and the fourth bridge arm 44 are mistakenly triggered before the first bridge arm 41 and the third bridge arm 43 are turned off, due to the existence of the impedance 22 in the damping circuit 2, the short-circuit current when the winding is short-circuited can also be reduced.

[0042] like Figure 1A plurality of controllable phase shifter control winding structures are connected in series to form a whole. When any of the controllable phase shifter control winding structures needs to be controlled and adjusted, the above method is used, and the original conducting bridge arm that does not need to be controlled and adjusted is maintained.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and are not intended to limit the present invention. A person skilled in the art should understand that the person skilled in the art may modify or replace the specific implementation of the present invention with equivalents, but these modifications or changes are within the scope of protection of the patent application to be approved.

Claims

1. A control method for a controllable phase shifter device, the controllable phase shifter device comprising a plurality of controllable windings connected in series, the controllable windings comprising a transformer secondary winding, a damping circuit and a full-bridge circuit; One end of the transformer secondary winding is connected to the input end of the damping circuit, and the output end of the damping circuit and the other end of the transformer secondary winding are respectively connected to the input end of the full-bridge circuit; or the two ends of the transformer secondary winding are respectively connected to the input end of a damping circuit, and the output ends of the two damping circuits are connected to the input end of the full-bridge circuit; The output ends of the three full-bridge circuits are connected in series in sequence; The damping loop is composed of an impedance and a switch in parallel, and the impedance is a resistor, or an inductor, or a resistor and an inductor in series, or a resistor and an inductor in parallel; The switch is a mechanical switch or a power electronic switch; The full-bridge circuit is composed of four bridge arms, each of which is composed of a plurality of anti-parallel thyristors; Features: When any controllable winding operates normally, the switch in the damping circuit is in the closed state, bypassing the impedance in the damping circuit; When the first bridge arm (41) and the third bridge arm (43) are turned on, or the second bridge arm (42) and the fourth bridge arm (44) are turned on, the output voltage of the full-bridge circuit is zero; When the first bridge arm (41) and the fourth bridge arm (44) are turned on, the output voltage of the full-bridge circuit is in phase with the transformer winding voltage; When the second bridge arm (42) and the third bridge arm (43) are turned on, the output voltage of the full-bridge circuit is in opposite phase to the transformer winding voltage; When any controllable winding needs to be adjusted arbitrarily in three states: the full-bridge circuit output voltage is zero, the full-bridge circuit output voltage is in phase with the transformer winding voltage, and the full-bridge circuit output voltage is in phase with the transformer winding voltage, the adjustment steps are as follows: S1, open the switch in the damping circuit and input impedance; S2, locks the two bridge arms that have been turned on; S3, after the current of the two bridge arms that have been turned on passes through zero and is turned off, the other two bridge arms that need to be turned on are triggered to be turned on; S4, closes the switch in the damping circuit to complete the conduction of the other two bridge arms.

2. The control method of the controllable phase shifter device according to claim 1, characterized in that: When any of the controllable windings needs to be adjusted, the steps S1 to S4 are executed; for the controllable windings that do not need to be adjusted, the originally turned-on bridge arm remains turned on.

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