CN-121984370-A - Three-phase to single-phase circuit and method for variable frequency power supply and storage medium

CN121984370ACN 121984370 ACN121984370 ACN 121984370ACN-121984370-A

Abstract

The invention relates to a circuit, a method and a storage medium for converting three phases of a variable frequency power supply into single phases, wherein the circuit for converting the three phases of the variable frequency power supply into the single phases comprises a control unit, an independent full-bridge single-phase inversion unit, a direct current bus unit, an output filter unit, a switching unit and an output end, wherein the direct current bus unit is respectively connected with the independent full-bridge single-phase inversion unit and the control unit, the output filter unit is connected with the control unit, the independent full-bridge single-phase inversion unit is connected with the output filter unit, the switching unit is connected with the control unit, the output filter unit is connected with the switching unit, the output end is connected with the control unit, and the output filter unit and the switching unit are respectively connected with the output end. Based on the control unit, the independent full-bridge single-phase inversion unit and the switching unit, the three-phase and single-phase mode impact-free rapid switching is realized by controlling the N-line switching and the waveform parameters, mechanical wiring adjustment is not needed, and the automatic scene requirement is met.

Inventors

YANG KONGLIN
ZHOU WU
LI CAIHONG

Assignees

广东数川科技有限公司

Dates

Publication Date: 20260505
Application Date: 20260227

Claims (10)

1. The utility model provides a variable frequency power supply three-phase changes single-phase circuit which characterized in that includes: a control unit (100); An independent full-bridge single-phase inversion unit (200); a direct current bus unit (300), wherein the direct current bus unit (300) is respectively connected with the independent full-bridge single-phase inversion unit (200) and the control unit (100); The output filtering unit (400), the output filtering unit (400) is connected with the control unit (100), and the independent full-bridge single-phase inversion unit (200) is connected with the output filtering unit (400); A switching unit (500), the switching unit (500) being connected to the control unit (100), the output filtering unit (400) being connected to the switching unit (500); The output end (600), the output end (600) is connected with the control unit (100), and the output filtering unit (400) and the switching unit (500) are respectively connected with the output end (600).
2. The three-phase to single-phase circuit of a variable frequency power supply according to claim 1, wherein, The DC bus unit (300) comprises a first live wire (U), a second live wire (V), a third live wire (W), a DC bus positive electrode (+VBus), a DC bus negative electrode (-VBus), a rectifier bridge (BR 1) and a bus filter capacitor module (Cbus), wherein the rectifier bridge (BR 1) is connected with the bus filter capacitor module (Cbus), the first live wire (U), the second live wire (V) and the third live wire (W) are respectively connected with the rectifier bridge (BR 1), the bus filter capacitor module (Cbus) is respectively connected with the DC bus positive electrode (+VBus) and the DC bus negative electrode (-VBus), The bus filter capacitor module (Cbus) comprises two rows of sub-connection structures which are connected in parallel, each sub-connection structure comprises a discharging resistor (R1) and a filter capacitor (C1), and the discharging resistors (R1) and the filter capacitors (C1) are alternately arranged and connected.
3. The three-phase to single-phase circuit of a variable frequency power supply according to claim 1, wherein, The independent full-bridge single-phase inversion unit (200) comprises an H-bridge inversion topology (Q1) and an isolation transformer (T1), wherein the H-bridge inversion topology (Q1) is connected with the isolation transformer (T1), and the H-bridge inversion topology (Q1) consists of 4 switching tubes (Q2); The output filter unit (400) comprises a capacitor (C2), an output filter plate (FLT 1) and an inversion end (Vinv), wherein the isolation transformer (T1) is connected with the capacitor (C2), the capacitor (C2) is connected with the output filter plate (FLT 1), and the output filter plate (FLT 1) is connected with the inversion end (Vinv).
4. The three-phase to single-phase circuit of a variable frequency power supply according to claim 1, wherein, The number of the independent full-bridge single-phase inversion units (200) is three, the number of the output filter units (400) is three, and the three independent full-bridge single-phase inversion units (200) are respectively connected with the three output filter units (400); The variable-frequency power supply three-phase-to-single-phase circuit comprises a fourth live wire (L1), a fifth live wire (L2) and a sixth live wire (L3), wherein the output filter unit (400) is respectively connected with the fourth live wire (L1), the fifth live wire (L2) and the sixth live wire (L3), and the fourth live wire (L1), the fifth live wire (L2) and the sixth live wire (L3) are respectively connected with the output end (600).
5. The three-phase to single-phase circuit of a variable frequency power supply according to claim 1, wherein, Including first zero line (N1), second zero line (N2) and third zero line (N3), three output filter unit (400) respectively with first zero line (N1), second zero line (N2) with third zero line (N3) are connected, first zero line (N1), second zero line (N2) and third zero line (N3) respectively with switching unit (500).
6. The three-phase to single-phase circuit of a variable frequency power supply according to claim 5, wherein, The switching unit (500) includes a relay group such that the combination and separation of the first neutral line (N1), the second neutral line (N2), and the third neutral line (N3) are controlled by the relay group.
7. A method for converting three phases of a variable frequency power supply into a single phase, applied to the variable frequency power supply three-phase to single phase circuit as claimed in any one of claims 1 to 6, comprising the following steps: S100, after a digital signal processing controller receives a mode switching instruction, detecting voltage and current signals output by a current load through an ADC acquisition unit, and calculating load power and characteristics; S200, a control signal is sent to a switching unit (500), a relay group of the switching unit (500) is driven to control the combination and separation of a first zero line (N1), a second zero line (N2) and a third zero line (N3) in a three-phase-to-single-phase circuit of the variable frequency power supply, and output waveform parameters of a EPWM unit are synchronously updated to realize seamless switching between a three-phase mode and a single-phase mode.
8. The method for converting three phases to single phase of a variable frequency power supply according to claim 7, In the three-phase mode, the digital signal processing controller is used for controlling the relay combination of the switching unit (500) and the first zero line (N1), the second zero line (N2) and the third zero line (N3) as public neutral lines to form a three-phase four-wire system output framework, the digital signal processing controller is controlled to generate SPWM waveforms with 120-degree phase difference through EPWM units, the SPWM waveforms are isolated and amplified through a driving circuit and then control the on-off time sequence of an H-bridge inversion topology (Q1), three independent full-bridge single-phase inversion units (200) are controlled to respectively output three-phase alternating currents, the output voltage effective values of the three-phase alternating currents are controlled by adjusting SPWM modulation ratios, and the output frequency of the three-phase alternating currents is set by adjusting the carrier period of EPWM units.
9. The method for converting three phases to single phase of a variable frequency power supply according to claim 7, In the single-phase mode, the first zero line (N1), the second zero line (N2) and the third zero line (N3) are independently separated by controlling the relay group of the switching unit (500) through the digital signal processing controller; when single-path single-phase output is performed, an independent full-bridge single-phase inversion unit (200) is selected as a working unit, and the digital signal processing controller is controlled to output SPWM waveforms with single frequency and phase; When the multi-path independent single-phase power supply is output, the digital signal processing controller synchronously controls the plurality of independent full-bridge single-phase inversion units (200) to generate SPWM waveforms with different phases, frequencies or voltage parameters so as to realize the multi-path independent adjustable single-phase power supply output and meet the multi-load differential power supply requirement.
10. A computer readable storage medium having stored thereon program instructions, which when executed by a processor implement the method of any of claims 7 to 9.

Description

Three-phase to single-phase circuit and method for variable frequency power supply and storage medium Technical Field The invention relates to the technical field of power control, in particular to a circuit, a method and a storage medium for converting three phases of a variable frequency power supply into single phases. Background In the technical field of power electronics, a variable-frequency power supply is used as a key testing and power supply device, and is widely applied to links such as industrial sites, scientific researches and product research and development, and the core task of the variable-frequency power supply is to provide an alternating-current power supply with continuously adjustable voltage and frequency for various loads. Currently, two main technical solutions are mainly formed on the market in face of multiphase load demand: the three-phase balanced output type power supply adopts a unified control strategy, can output stable and symmetrical three-phase alternating current, and is suitable for load tests of three-phase motors, three-phase transformers and the like needing balanced power supply. However, the three-phase voltages, frequencies and phases are mutually coupled and strictly synchronous, and cannot be independently adjusted. The multi-channel independent single-phase output type power supply is formed by integrating a plurality of completely independent single-phase frequency conversion modules, each module can independently output single-phase alternating currents with different voltages and frequencies and can simultaneously supply power for a plurality of single-phase loads, however, channels are completely isolated electrically and cannot cooperate to simulate a unified three-phase balance system. The fundamental defect of the related technology is that the three-phase balance output and the three-path independently adjustable single-phase output can only be selected from two, and cannot be compatible. The limitation makes practical application face significant cost and efficiency problems that when testing environment is required to test both three-phase power supply samples and a plurality of single-phase samples with inconsistent power supply requirements, users only need to purchase two types of power supply equipment respectively, the equipment investment is doubled, the laboratory space is occupied in a large amount, equipment is required to be frequently switched and the lines are changed in the testing process, the operation is complex, the efficiency is low, and resources are seriously wasted. Disclosure of Invention The invention provides a circuit, a method and a storage medium for converting three phases of a variable frequency power supply into single phases, and aims to at least solve one of the technical problems in the prior art. The technical scheme of the invention is a circuit for converting three phases of a variable frequency power supply into single phases, which comprises the following components: a control unit; an independent full-bridge single-phase inversion unit; The direct-current bus unit is respectively connected with the independent full-bridge single-phase inversion unit and the control unit; The output filtering unit is connected with the control unit, and the independent full-bridge single-phase inversion unit is connected with the output filtering unit; the switching unit is connected with the control unit, and the output filtering unit is connected with the switching unit; The output end is connected with the control unit, and the output filtering unit and the switching unit are respectively connected with the output end. According to some embodiments of the present invention, the dc bus unit includes a first live wire, a second live wire, a third live wire, a dc bus positive electrode, a dc bus negative electrode, a rectifier bridge and a bus filter capacitor module, where the rectifier bridge is connected to the bus filter capacitor module, the first live wire, the second live wire and the third live wire are respectively connected to the rectifier bridge, the bus filter capacitor module is respectively connected to the dc bus positive electrode and the dc bus negative electrode, the bus filter capacitor module includes two rows of sub-connection structures connected in parallel, and the sub-connection structures include a discharge resistor and a filter capacitor, and the discharge resistor and the filter capacitor are alternately arranged and connected. According to some embodiments of the invention, the independent full-bridge single-phase inversion unit comprises an H-bridge inversion topology and an isolation transformer, wherein the H-bridge inversion topology is connected with the isolation transformer and consists of 4 switching tubes, the output filter unit comprises a capacitor, an output filter plate and an inversion end, the isolation transformer is connected with the capacitor, the capacitor is connected with the o