Three-phase frequency-adjustable phase-shift power supply

Abstract

The utility model discloses a three-phase frequency-adjustable phase-shift power supply, which comprises a three-phase wire inlet connector, a bridge arm circuit and an STM32 control panel, the three-phase wire inlet connector is electrically connected with a rectifier bridge, the rectifier bridge is electrically connected with a direct-current filter inductor L1, the direct-current filter inductor L1 is electrically connected with a filter capacitor circuit, and the filter capacitor circuit is electrically connected with the bridge arm circuit. The rectifier bridge, the direct-current filter inductor L1 and the filter capacitor circuit provide direct current for a loop, the bridge arm circuit is electrically connected with the filter capacitor circuit, the bridge arm circuit comprises Q1, Q2, Q3, Q4, Q5 and Q6, the bridge arm circuit is electrically connected with an output terminal, the STM32 control panel is electrically connected with a DDS signal generator, the DDS signal generator is electrically connected with a three-phase pre-amplifier, and the three-phase pre-amplifier is electrically connected with the bridge arm circuit. The three-phase pre-stage amplifier is electrically connected with the bridge arm circuit, the STM32 control panel generates a command to the DDS signal generator to generate a digital synthesis waveform, the digital synthesis waveform drives the bridge arm circuit through the three-phase pre-stage amplifier, and a three-phase four-wire system is formed by output terminals for output.

Description

Technical Field

[0001] The utility model relates to the technical field of electric power testing, in particular to a three-phase frequency-adjustable phase-shifting power supply. Background Art

[0002] Currently, high-voltage power operating equipment is required to undergo a handover test after installation and commissioning, and before it is officially energized and put into operation. When outdoors, a large mobile power supply will be used to power the power test equipment.

[0003] Since there are many types of power test equipment, such as mutual inductors and power protection devices, it is necessary to provide different frequencies, three-phase and single-phase power to the power test equipment. At present, large mobile power supplies are equipped with inverters, converters and other components to meet different power outputs and used as external devices. This method requires the disassembly and assembly of external devices every time a large mobile power supply is used, and more equipment needs to be transported; when checking whether the power protection device is normal, a special power output system is also required, which is not convenient for outdoor use. Utility Model Content

[0004] The purpose of the utility model is to provide a three-phase adjustable frequency phase-shifting power supply to solve the problems raised in the above background technology.

[0005] To achieve the above object, the utility model provides the following technical solutions: a three-phase adjustable frequency phase-shifting power supply, comprising a three-phase incoming line connector, inputting 380 volts of alternating current, the three-phase incoming line connector being electrically connected to a rectifier bridge (D1, D2, D3, D4, D5, D6), the rectifier bridge being electrically connected to a DC filter inductor L1, the DC filter inductor L1 being electrically connected to a filter capacitor circuit, the rectifier bridge, the DC filter inductor L1, and the filter capacitor circuit providing DC power for the loop;

[0006] Output power through positive polarity DC+ and negative polarity DC- to provide power for devices using direct current and provide DC output function;

[0007] A bridge arm circuit, the bridge arm circuit is electrically connected to the filter capacitor circuit, the bridge arm circuit comprises Q1, Q2, Q3, Q4, Q5, Q6, and the bridge arm circuit is electrically connected to an output terminal;

[0008] An STM32 control board, wherein the STM32 control board is electrically connected to a DDS signal generator, wherein the DDS signal generator is electrically connected to a three-phase pre-amplifier, and wherein the three-phase pre-amplifier is electrically connected to a bridge arm circuit;

[0009] The STM32 control board generates a command to the DDS signal generator to generate a digital synthesized waveform. When three 120-degree phase difference sinusoidal signals are generated, the digital synthesized waveform drives the bridge arm circuit through a three-phase preamplifier, and the output terminals form a three-phase four-wire output.

[0010] Furthermore, the bridge arm circuit is composed of several transistors connected in parallel, and each of them has a freewheeling diode. The transistor can also be used as an amplifier to amplify the input signal and output it to the load. When the transistor is turned off, there may be induced electromotive force or residual charge between its collector and emitter. The freewheeling diode provides a discharge path for these charges, preventing the accumulation of high voltage and improving the stability of the circuit.

[0011] Furthermore, the output terminals include OUTA, OUTB, OUTC, and OUTO. After OUTA, OUTB, and OUTC are connected in parallel, they form a single-phase power output with OUTO, which can meet conventional power tests.

[0012] Compared with the prior art, the beneficial effects of the utility model are:

[0013] (1) The STM32 control board generates a command to the DDS signal generator to generate a digital synthetic waveform. When three 120-degree phase difference sinusoidal signals are generated, they are driven by the three-phase preamplifier to drive six bridge arms (, and the output terminals form a three-phase four-wire output. It has frequency modulation, voltage regulation and phase shifting functions, which can power a variety of devices and has more complete functions.

[0014] (2) It adopts the principle of triode linear amplification, and can output three-phase / single-phase, with adjustable frequency and phase. It can not only output 50Hz, but also calibrate the transformer rated at 60Hz. Because the power supply system works in linear amplification mode, it can output triple frequency 150Hz in single-phase mode, and can be used as the inductive withstand voltage and partial discharge test source of voltage transformer.

[0015] (3) The output frequency phase can be adjusted through the DDS signal generator. At this time, some fault conditions can be simulated to verify whether the power protection device is in normal working condition. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a circuit diagram of the utility model. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0018] Example:

[0019] See also Figure 1 The utility model provides a technical solution: a three-phase adjustable frequency phase-shifting power supply, comprising a three-phase incoming line connector, the three-phase incoming line connector is electrically connected to a rectifier bridge, the rectifier bridge is electrically connected to a DC filter inductor L1, the DC filter inductor L1 is electrically connected to a filter capacitor circuit, the rectifier bridge, the DC filter inductor L1, and the filter capacitor circuit provide DC power for the loop;

[0020] The three-phase incoming line connector is connected to 380V AC power, and the rectifier bridge is used to rectify the positive and negative half cycles of the three phases of the three-phase AC power respectively, so as to obtain a smooth DC output;

[0021] The main function of the DC filter inductor L1 is to filter out high-frequency noise and ripples in the power, making the output power smoother and more stable. At the same time, the DC filter inductor L1 can also provide a certain DC impedance, limit the sudden change of current, and protect other components in the circuit;

[0022] A bridge arm circuit, the bridge arm circuit is electrically connected to the filter capacitor circuit, the bridge arm circuit comprises Q1, Q2, Q3, Q4, Q5, Q6, and the bridge arm circuit is electrically connected to an output terminal;

[0023] STM32 control board, the STM32 control board is electrically connected to a DDS signal generator, the DDS signal generator is electrically connected to a three-phase pre-amplifier, the three-phase pre-amplifier is electrically connected to the bridge arm circuit, and the STM32 control board mainly receives and analyzes instructions sent by the host computer, and controls the corresponding hardware circuit to perform corresponding actions;

[0024] The STM32 control board generates a command to the DDS signal generator to generate a digital synthesized waveform. When three 120-degree phase difference sinusoidal signals are generated, the digital synthesized waveform drives the bridge arm circuit through a three-phase preamplifier, and the output terminals form a three-phase four-wire output.

[0025] In this embodiment, the DDS signal generator uses two AD9767 dual-channel DAC chips as the core, and the power / ground pins of the chip are DVDD, DCOM, AVDD and ACOM, among which DVDD and DCOM are the power / ground of digital signals; AVDD and ACOM are the power / ground of analog signals.

[0026] In this embodiment, if Figure 1 As shown, the rectifier bridge includes D1, D2, D3, D4, D5, and D6. D1, D2, D3, D4, D5, and D6 are connected in parallel with the three-phase incoming line connector to form a bridge structure.

[0027] In this embodiment, if Figure 1 As shown, the filter capacitor circuit includes C1 and C2 connected in series, which filters out noise in the AC signal and generates a stable voltage across the capacitor.

[0028] In this embodiment, if Figure 1 As shown, the bridge arm circuit is composed of several transistors connected in parallel, and all of them are equipped with freewheeling diodes. The transistor can be used as a switch. By controlling its base current, the resistance between its collector and emitter can be low or high, thereby realizing the switching function of the circuit. When the transistor is turned off, there may be induced electromotive force or residual charge between its collector and emitter. The freewheeling diode provides a discharge path for these charges, preventing the accumulation of high voltage.

[0029] In this embodiment, if Figure 1 As shown, the output terminals include OUTA, OUTB, OUTC, and OUTO for outputting power.

[0030] Specifically, when in use, the main circuit is composed of: the three-phase incoming line passes through the rectifier bridge, enters the DC filter inductor L1 and the filter capacitor point library (C1, C2), which can provide a DC power supply (positive polarity DC+, negative polarity DC-) for the circuit, and each bridge arm circuit (Q1, Q2, Q3, Q4, Q5, Q6) is composed of multiple transistors in parallel, and all have freewheeling diodes;

[0031] Output mode: The STM32 control board sends a command to the DDS signal generator to generate a digital synthetic waveform. When three 120-degree phase difference sinusoidal signals are generated, they are driven by the three-phase preamplifier to drive six bridge arms, and the output terminals (OUTA, OUTB, OUTC, OUTO) form a three-phase four-wire output; by controlling the DDS signal generator, the output frequency phase can be adjusted, and some fault conditions can be simulated. When the DDS signal generator outputs three signals with the same phase, OUTA, OUTB, and OUTC can be connected in parallel to form a single-phase power output with OUTO, which can meet the test frequencies required for conventional power tests, such as 50Hz, 60Hz, 150Hz, etc., and can be suitable for small-capacity dry PT triple frequency withstand voltage and partial discharge test power supply.

[0032] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A three-phase adjustable frequency phase-shifting power supply, characterized in that: include: A three-phase incoming line connector, wherein the three-phase incoming line connector is electrically connected to a rectifier bridge, wherein the rectifier bridge is electrically connected to a DC filter inductor L1, wherein the DC filter inductor L1 is electrically connected to a filter capacitor circuit, wherein the rectifier bridge, the DC filter inductor L1, and the filter capacitor circuit provide DC power for the loop; A bridge arm circuit, the bridge arm circuit is electrically connected to the filter capacitor circuit, and the bridge arm circuit is electrically connected to an output terminal; An STM32 control board, wherein the STM32 control board is electrically connected to a DDS signal generator, wherein the DDS signal generator is electrically connected to a three-phase pre-amplifier, and wherein the three-phase pre-amplifier is electrically connected to a bridge arm circuit; The STM32 control board generates a command to the DDS signal generator to generate a digital synthesis waveform, and the digital synthesis waveform drives the bridge arm circuit through a three-phase pre-amplifier, and the output terminals form a three-phase four-wire output.

2. A three-phase adjustable frequency phase-shifting power supply according to claim 1, characterized in that: The DDS signal generator uses two AD9767 dual-channel DAC chips as the core.

3. A three-phase adjustable frequency phase-shifting power supply according to claim 1, characterized in that: The rectifier bridge includes D1, D2, D3, D4, D5, and D6.

4. A three-phase adjustable frequency phase-shifting power supply according to claim 1, characterized in that: The filter capacitor circuit includes C1 and C2 connected in series.

5. A three-phase adjustable frequency phase-shifting power supply according to claim 1, characterized in that: The bridge arm circuit comprises a plurality of transistors Q1, Q2, Q3, Q4, Q5 and Q6 connected in parallel, and each transistor is provided with a freewheeling diode.

6. A three-phase adjustable frequency phase-shifting power supply according to claim 1, characterized in that: The output terminals include OUTA, OUTB, OUTC, and OUTO.

7. A three-phase adjustable frequency phase-shifting power supply according to claim 1, characterized in that: 380 VAC is connected to the three-phase incoming line connector.

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