Alternating-current variable-frequency power supply capable of realizing three-phase-to-single-phase full-power output

Abstract

The utility model discloses an alternating-current variable-frequency power supply capable of realizing three-phase-to-single-phase full-power output, which comprises a main board, a slow starting module, a three-phase EMI (Electro-Magnetic Interference) filter, an R-phase output isolation transformer, an S-phase output isolation transformer, a T-phase output isolation transformer and a three-to-single interlocking switching contactor, the main board is provided with an output voltage sampling end pin, an output current sampling end pin, an SPP-107, an operation panel removing end pin, a driving signal end pin and a slow start removing end pin, and the main board is connected with the slow start module through the slow start removing end pin. The power supply does not need to additionally purchase single-phase power supply equipment and can be directly switched; compared with a voltage regulator scheme, a variable-frequency power supply is used for supplying power and is isolated from a mains supply power grid, so that the anti-interference performance is improved; an interlocking mechanism is arranged between the single phase and the three phases, so that the single-phase output and the three-phase output are prevented from being mistakenly connected, and the tested equipment is prevented from being damaged.

Description

Technical Field

[0001] This utility model relates to the field of AC variable frequency power supply technology, specifically an AC variable frequency power supply capable of converting three-phase to single-phase full-power output. Background Technology

[0002] In current laboratory testing power supplies, with the increasing power and diversity of load types, ordinary three-phase output frequency converters, due to their power limitations, cannot meet the needs of single-phase loads. Therefore, technologies have been developed to combine three-phase power into single-phase full-power output with on-demand switching capabilities. In the power conditioning field, voltage regulators are currently widely used tools. Additionally, purchasing a single-phase power supply is another option. Commercially available testing power supplies often use high-current single-phase mains power for testing; adding a single-phase high-power frequency converter station is also an option.

[0003] However, traditional testing methods have the following drawbacks:

[0004] (1) Direct testing cannot guarantee the isolation and safety of the experimental power supply requirements, and an isolation transformer is required, but it cannot meet the requirements of the simulated external network environment that requires frequency conversion;

[0005] (2) It increases the laboratory resources occupied by the workstation. When changing the load type, the cable needs to be reconnected. When the equipment requires a high-power single-phase frequency converter power input, the input power supply needs to be changed to a high-power single-phase input power supply, which requires stopping the machine to change the cable. Changing the cable or power supply is not conducive to the efficiency of experimental testing. Purchasing a high-power single-phase power supply separately is not conducive to improving experimental efficiency and the price is high, resulting in a significant cost disadvantage. Utility Model Content

[0006] The purpose of this invention is to provide an AC frequency converter power supply capable of converting three-phase to single-phase full-power output, addressing the issues raised in the background art. Direct testing cannot guarantee the isolation and safety of the experimental power supply requirements, necessitating the use of an isolation transformer, which fails to meet the needs of simulated external network environments requiring frequency conversion. Furthermore, it increases the occupation of laboratory resources, requires re-connecting cables when changing load types, and necessitates switching the input power supply to a high-power single-phase power supply when high-power single-phase input is required, necessitating downtime for cable replacement, which is detrimental to experimental testing efficiency. Purchasing a separate high-power single-phase power supply is also inefficient and expensive, resulting in a significant cost disadvantage.

[0007] To achieve the above objectives, this utility model provides the following technical solution: an AC frequency converter power supply capable of three-phase to single-phase full-power output, comprising a main board, a slow start module, a three-phase EMI filter, an R-phase output isolation transformer, an S-phase output isolation transformer, a T-phase output isolation transformer, and a three-to-single interlocking contactor. The main board is provided with an output voltage sampling pin, an output current sampling pin, an SPP-107, a connection to the operation panel pin, a drive signal pin, and a slow start pin. The main board is connected to the slow start module via the slow start pin. The slow start module is connected to the three-phase EMI filter, the R-phase output isolation transformer, the S-phase output isolation transformer, and the T-phase output isolation transformer. The main board is connected to the R-phase output isolation transformer, the S-phase output isolation transformer, and the T-phase output isolation transformer via the drive signal pin. The R-phase output isolation transformer, the S-phase output isolation transformer, and the T-phase output isolation transformer are all connected to the three-to-single interlocking contactor. An external interface is provided on the surface of the main board, and the main board is communicatively connected to an operation panel via the operation panel connection pin.

[0008] Preferably, the slow start module includes resistor R1, switch S1, resistor R6, switch S2, resistor R7, and switch S3. The 8 pins of the three-phase EMI filter are connected to pins 1 of resistor R1 and 1 of switch S1, respectively. The 7 pins of the three-phase EMI filter are connected to pins 1 of resistor R6 and 1 of switch S2, respectively. The 6 pins of the three-phase EMI filter are connected to pins 1 of resistor R7 and 1 of switch S3, respectively. Resistor R1 is connected in parallel with switch S1. Resistor R6 is connected in parallel with switch S2, resistor R7 is connected in parallel with switch S3, pins 2 of switch S1 are connected to pin K of diode D1 and pin A of diode D2, pins 2 of switch S2 are connected to pin K of diode D3 and pin A of diode D4, pins 2 of switch S3 are connected to pin K of diode D5 and pin A of diode D6, and pins A of diode D1, D3, and D5 are connected in parallel with switch S2. Pin A is connected to microcontrollers EC1, EC2, EC3, and EC4. Pin 2 of microcontroller EC1 is connected to microcontroller EC8. Pin 2 of microcontroller EC2 is connected to microcontroller EC7. Pin 2 of microcontroller EC3 is connected to microcontroller EC5. Pin 2 of microcontroller EC4 is connected to microcontroller EC6. Pin 1 of microcontroller EC4 is connected to resistors R2 and R3. Pin 1 of microcontroller EC6 is connected to resistors R8 and R9. Pins K of diodes D2, D4, and D6, pins 2 of microcontroller EC8, pins 2 of microcontroller EC7, pin 2 of microcontroller EC5, pin 6 of microcontroller EC8, pins 1 of resistor R8, and pin 1 of resistor R9 are all grounded. The surface of microcontroller EC4 is connected to the R-phase output isolation transformer, the S-phase output isolation transformer, and the T-phase output isolation transformer, respectively.

[0009] Preferably, the R-phase output isolation transformer includes a fuse F1, transistors Q1, Q2, Q3, and Q4, an R-phase IGBT driver, a transformer T1, a resistor R4, and capacitors C4, C6, C7, and C1. Two terminals of the fuse F1 are connected to two terminals of transistor Q1, one end of capacitor C1, and two terminals of transistor Q3, respectively. Three terminals of transistor Q1 are connected to two terminals of transistor Q2 and one end of transformer T1, respectively. Three terminals of transistor Q3 are connected to three... Pin 2 of transistor Q4 is connected to pin 4 of transformer T1. Pins 1 of transistor Q1 and Q2 are both connected to one end of the R-phase IGBT driver. Pin 1 of transformer T1 is connected to pin 1 of resistor R4, one end of capacitor C6, and one end of capacitor C7. Pin 2 of transformer T1 is connected to one end of capacitor C4, the other end of capacitor C6, and the other end of capacitor C7. Pin 2 of resistor R4 is connected to the other end of capacitor C4. The other end of the R-phase IGBT driver is connected to the motherboard.

[0010] Preferably, the S-phase output isolation transformer includes a fuse F2, transistors Q5, Q2, Q7, Q8, an S-phase IGBT driver, a transformer T2, a resistor R5, capacitors C3, C5, C8, and C2. Two terminals of the fuse F2 are connected to two terminals of transistor Q5, one end of capacitor C2, and two terminals of transistor Q7, respectively. Three terminals of transistor Q5 are connected to two terminals of transistor Q2 and one end of transformer T2, respectively. Three terminals of transistor Q7 are connected to three terminals of the transformer T2, respectively. Pin 2 of transistor Q8 is connected to pin 4 of transformer T2. Pins 1 of transistor Q5 and pin 1 of transistor Q2 are both connected to one end of the S-phase IGBT driver. Pin 1 of transformer T2 is connected to pin 1 of resistor R5, one end of capacitor C5, and one end of capacitor C8. Pin 2 of transformer T2 is connected to one end of capacitor C3, the other end of capacitor C5, and the other end of capacitor C8. Pin 2 of resistor R5 is connected to the other end of capacitor C3. The other end of the S-phase IGBT driver is connected to the motherboard.

[0011] Preferably, the T-phase output isolation transformer includes a fuse F3, transistors Q9, Q2, Q11, Q12, a T-phase IGBT driver, a transformer T3, a resistor R10, and capacitors C9, C10, C11, and C15. Two terminals of the fuse F3 are connected to two terminals of transistor Q9, one end of capacitor C15, and two terminals of transistor Q11, respectively. Three terminals of transistor Q9 are connected to two terminals of transistor Q2 and three terminals of transformer T3, respectively. Three terminals of transistor Q11 are connected to... Pin 2 of transistor Q12 is connected to pin 4 of transformer T3. Pins 1 of transistors Q9 and Q2 are both connected to one end of the T-phase IGBT driver. Pin 1 of transformer T3 is connected to pin 1 of resistor R10, one end of capacitor C10, and one end of capacitor C11. Pin 2 of transformer T3 is connected to one end of capacitor C9, the other end of capacitor C10, and the other end of capacitor C11. Pin 2 of resistor R10 is connected to the other end of capacitor C9. The other end of the T-phase IGBT driver is connected to the motherboard.

[0012] Preferably, the three-way single-interlock switching contactor includes connectors J11, J12, and J13. Pin 1 of connector J11 is connected to output T (J7-1), pin 1 of connector J12 is connected to output S (J5-1), and pin 1 of connector J13 is connected to output R (J4-1). Pins 2 of connector J11 are respectively connected to transformer T4 and current transformer CT3, and pins 2 of connector J12 are connected to current transformer CT2. Pins 2 of connector J13 are connected to transformer T5 and current transformer CT1 respectively. Pins 2 of current transformer CT3 are connected to transformer T6. Pins 2 of transformer T4, pin 1 of transformer T5, and pins 2 of transformer T6 are all connected to capacitor CY. One end of capacitor CY is connected to switch S4. Pin 1 of switch S4 is grounded. Pins 3 of connector J11, pin 3 of connector J12, and pin 3 of connector J13 are all connected to J14-1.

[0013] Preferably, pin 1 of the three-phase EMI filter is connected to input AJ1-1, pin 2 of the three-phase EMI filter is connected to input BJ2-1, pin 3 of the three-phase EMI filter is connected to input CJ6-1, pin 4 of the three-phase EMI filter is connected to input NJ10-1, and pin 6 of the three-phase EMI filter is grounded.

[0014] Compared with the prior art, the advantages of this utility model are: the power supply does not require the purchase of additional single-phase power supply equipment and can be directly switched; compared with the voltage regulator solution, the use of frequency converter power supply isolates it from the mains power grid and improves anti-interference performance; because there is an interlocking mechanism between single-phase and three-phase, it avoids incorrect connection of single-phase and three-phase outputs, thereby preventing damage to the equipment under test. Attached Figure Description

[0015] Figure 1 This is the overall circuit diagram of this utility model;

[0016] Figure 2 This is one of the circuit diagrams of this utility model;

[0017] Figure 3 This is the second circuit diagram of this utility model;

[0018] Figure 4 This is the third circuit diagram of this utility model;

[0019] Figure 5 This is the fourth circuit diagram of this utility model;

[0020] Figure 6 This is the fifth circuit diagram of this utility model.

[0021] In the diagram: 1. Mainboard; 2. Slow start module; 3. Three-phase EMI filter; 4. R-phase output isolation transformer; 5. S-phase output isolation transformer; 6. T-phase output isolation transformer; 7. Three-to-single interlocking contactor; 8. Operation panel. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0023] Please see Figure 1-6This utility model provides an AC frequency converter power supply capable of three-phase to single-phase full-power output, including a main board 1, a slow start module 2, a three-phase EMI filter 3, an R-phase output isolation transformer 4, an S-phase output isolation transformer 5, a T-phase output isolation transformer 6, and a three-to-single interlocking contactor 7. The main board 1 is characterized by having an output voltage sampling pin, an output current sampling pin, an SPP-107, a connection to the operation panel pin, a drive signal pin, and a slow start pin. The main board 1 is connected to the slow start module 2 via the slow start pin. The slow start module 2 is connected to the three-phase EMI filter 3, the R-phase output isolation transformer 4, the S-phase output isolation transformer 5, and the T-phase output isolation transformer 6. The main board 1 is connected to the R-phase output isolation transformer 4, the S-phase output isolation transformer 5, and the T-phase output isolation transformer 6 via the drive signal pin. All three phases of the R-phase output isolation transformer 4, the S-phase output isolation transformer 5, and the T-phase output isolation transformer 6 are connected to the three-to-single interlocking contactor 7. An external interface is provided on the surface of the main board 1, and the main board 1 is connected to an operation panel 8 via the operation panel pin.

[0024] The slow-start module 2 includes resistor R1, switch S1, resistor R6, switch S2, resistor R7, and switch S3. Pin 8 of the three-phase EMI filter 3 is connected to pin 1 of resistor R1 and pin 1 of switch S1, pin 7 of the three-phase EMI filter 3 is connected to pin 1 of resistor R6 and pin 1 of switch S2, and pin 6 of the three-phase EMI filter 3 is connected to pin 1 of resistor R7 and pin 1 of switch S3. Resistor R1 and switch S1 are connected in parallel. Resistor R6 is connected in parallel with switch S2, and resistor R7 is connected in parallel with switch S3. Pins 2 of switch S1 are connected to pin K of diode D1 and pin A of diode D2, respectively. Pins 2 of switch S2 are connected to pin K of diode D3 and pin A of diode D4, respectively. Pins 2 of switch S3 are connected to pin K of diode D5 and pin A of diode D6, respectively. Pins A of diodes D1, D3, and D5 are all connected in parallel with switch S2. Microcontrollers EC1, EC2, EC3, and EC4 are connected. Pin 2 of microcontroller EC1 is connected to microcontroller EC8, pin 2 of microcontroller EC2 is connected to microcontroller EC7, pin 2 of microcontroller EC3 is connected to microcontroller EC5, pin 2 of microcontroller EC4 is connected to microcontroller EC6, pin 1 of microcontroller EC4 is connected to resistors R2 and R3, pin 1 of microcontroller EC6 is connected to resistors R8 and R9, pins K of diodes D2, D4, and D6, pins 2 of microcontroller EC8, pins 2 of microcontroller EC7, pins 2 of microcontroller EC5, pin 6 of microcontroller EC8, pins 1 of resistors R8 and R9 are all grounded, and the surface of microcontroller EC4 is connected to R-phase output isolation transformer 4, S-phase output isolation transformer 5, and T-phase output isolation transformer 6, respectively.

[0025] The R-phase output isolation transformer 4 includes a fuse F1, transistors Q1, Q2, Q3, and Q4, an R-phase IGBT driver, a transformer T1, a resistor R4, and capacitors C4, C6, C7, and C1. Two terminals of fuse F1 are connected to two terminals of transistor Q1, one end of capacitor C1, and two terminals of transistor Q3. Three terminals of transistor Q1 are connected to two terminals of transistor Q2 and three terminals of transformer T1. Three terminals of transistor Q3 are connected to... Pin 2 of transistor Q4 is connected to pin 4 of transformer T1. Pins 1 of transistors Q1 and Q2 are both connected to one end of the R-phase IGBT driver. Pin 1 of transformer T1 is connected to pin 1 of resistor R4, one end of capacitor C6, and one end of capacitor C7. Pin 2 of transformer T1 is connected to one end of capacitor C4, the other end of capacitor C6, and the other end of capacitor C7. Pin 2 of resistor R4 is connected to the other end of capacitor C4. The other end of the R-phase IGBT driver is connected to motherboard 1.

[0026] The S-phase output isolation transformer 5 includes a fuse F2, transistors Q5, Q2, Q7, Q8, an S-phase IGBT driver, a transformer T2, a resistor R5, and capacitors C3, C5, C8, and C2. Two terminals of fuse F2 are connected to two terminals of transistor Q5, one end of capacitor C2, and two terminals of transistor Q7. Three terminals of transistor Q5 are connected to two terminals of transistor Q2 and three terminals of transformer T2. Three terminals of transistor Q7 are connected to... Pin 2 of transistor Q8 is connected to pin 4 of transformer T2. Pins 1 of transistor Q5 and pin 1 of transistor Q2 are both connected to one end of the S-phase IGBT driver. Pin 1 of transformer T2 is connected to pin 1 of resistor R5, one end of capacitor C5, and one end of capacitor C8. Pin 2 of transformer T2 is connected to one end of capacitor C3, the other end of capacitor C5, and the other end of capacitor C8. Pin 2 of resistor R5 is connected to the other end of capacitor C3. The other end of the S-phase IGBT driver is connected to motherboard 1.

[0027] The T-phase output isolation transformer 6 includes fuse F3, transistors Q9, Q2, Q11, Q12, a T-phase IGBT driver, transformer T3, resistor R10, and capacitors C9, C10, C11, and C15. Two terminals of fuse F3 are connected to two terminals of transistor Q9, one end of capacitor C15, and two terminals of transistor Q11. Three terminals of transistor Q9 are connected to two terminals of transistor Q2 and three terminals of transformer T3. Three terminals of transistor Q11 are connected to three... Pin 2 of transistor Q12 is connected to pin 4 of transformer T3. Pins 1 of transistors Q9 and Q2 are both connected to one end of the T-phase IGBT driver. Pin 1 of transformer T3 is connected to pin 1 of resistor R10, one end of capacitor C10, and one end of capacitor C11. Pin 2 of transformer T3 is connected to one end of capacitor C9, the other end of capacitor C10, and the other end of capacitor C11. Pin 2 of resistor R10 is connected to the other end of capacitor C9. The other end of the T-phase IGBT driver is connected to motherboard 1.

[0028] The three-way single-interlock switching contactor 7 includes connectors J11, J12, and J13. Pin 1 of connector J11 is connected to output T (J7-1), pin 1 of connector J12 is connected to output S (J5-1), and pin 1 of connector J13 is connected to output R (J4-1). Pins 2 of connector J11 are connected to transformer T4 and current transformer CT3, respectively. Pins 2 of connector J12 are connected to current transformer CT2. Pins 13 are connected to transformer T5 and current transformer CT1 respectively. Pins 2 of current transformer CT3 are connected to transformer T6. Pins 2 of transformer T4, pin 1 of transformer T5, and pins 2 of transformer T6 are all connected to capacitor CY. One end of capacitor CY is connected to switch S4. Pin 1 of switch S4 is grounded. Pins 3 of connector J11, pins 3 of connector J12, and pins 3 of connector J13 are all connected to J14-1.

[0029] The three-phase EMI filter 3 has input AJ1-1 connected to pin 1, input BJ2-1 connected to pin 2, input CJ6-1 connected to pin 3, input NJ10-1 connected to pin 4, and pin 6 grounded.

[0030] In this embodiment, the standard ±120° three-phase frequency converter is converted into a single-phase output by synchronizing the phases. The three-phase power units require the other two sets of drive signals to be isolated, and the main phase drives the three power units to achieve output phase synchronization. The device for isolating the drive signals is a "three-to-single" logic switching board (SPP-107), equipped with an external indicator light for the current output mode and an interlocking contactor mechanism for a "two-to-one" output mode selection. The "three-to-single" logic switching board is located between the main board 1 of the ordinary three-phase frequency converter and the power units. It is used to isolate the drive signals of the secondary phase and synchronize the output three-phase phases when switching to single-phase mode. The three-phase and single-phase modes can be switched directly on the operation panel 8 and cannot be switched while in output mode to avoid misoperation. The output terminal blocks are one three-phase and one single-phase, with a "two-to-one" logical relationship to avoid incorrect load type connection.

[0031] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A three-phase to single-phase full power output AC frequency conversion power supply, comprising a main board (1), a slow start module (2), a three-phase EMI filter (3), an R-phase output isolation transformer (4), an S-phase output isolation transformer (5), a T-phase output isolation transformer (6) and a three-to-single interlocking switching contactor (7), characterized in that: The main board (1) is provided with output voltage sampling end pin, output current sampling end pin, SPP-107, operation panel removing end pin, driving signal end pin and slow start removing end pin, the main board (1) is connected with the slow start module (2) through the slow start removing end pin, the slow start module (2) is connected with the three-phase EMI filter (3), R-phase output isolation transformer (4), S-phase output isolation transformer (5) and T-phase output isolation transformer (6), the main board (1) is connected with the R-phase output isolation transformer (4), S-phase output isolation transformer (5) and T-phase output isolation transformer (6) through the driving signal end pin, the R-phase output isolation transformer (4), S-phase output isolation transformer (5) and T-phase output isolation transformer (6) are connected with the three-trans single interlocking switching contactor (7), the surface of the main board (1) is provided with an external interface, and the main board (1) is connected with the operation panel (8) in communication through the operation panel removing end pin (8).

2. The three-phase-to-single-phase full power output AC frequency conversion power supply according to claim 1, characterized in that: The slow start module (2) includes resistors R1, switches S1, resistors R6, switches S2, resistors R7 and switches S3, the 8 pins of the three-phase EMI filter (3) are connected with the 1 pin of the resistor R1 and the 1 pin of the switch S1 respectively, the 7 pins of the three-phase EMI filter (3) are connected with the 1 pin of the resistor R6 and the 1 pin of the switch S2 respectively, the 6 pins of the three-phase EMI filter (3) are connected with the 1 pin of the resistor R7 and the 1 pin of the switch S3 respectively, the resistor R1 is connected with the switch S1 in parallel, the resistor R6 is connected with the switch S2 in parallel, the resistor R7 is connected with the switch S3 in parallel, the 2 pin of the switch S1 is connected with the K pin of the diode D1 and the A pin of the diode D2 respectively, the 2 pin of the switch S2 is connected with the K pin of the diode D3 and the A pin of the diode D4 respectively, the 2 pin of the switch S3 is connected with the K pin of the diode D5 and the A pin of the diode D6 respectively, the A pin of the diode D1, the A pin of the diode D3 and the A pin of the diode D5 are connected with the microcontroller EC1, the microcontroller EC2, the microcontroller EC3 and the microcontroller EC4, the 2 pin of the microcontroller EC1 is connected with the microcontroller EC8, the 2 pin of the microcontroller EC2 is connected with the microcontroller EC7, the 2 pin of the microcontroller EC3 is connected with the microcontroller EC5, the 2 pin of the microcontroller EC4 is connected with the microcontroller EC6, the 1 pin of the microcontroller EC4 is connected with the resistor R2 and the resistor R3, the 1 pin of the microcontroller EC6 is connected with the resistor R8 and the resistor R9, the K pin of the diode D2, the K pin of the diode D4, the K pin of the diode D6, the 2 pin of the microcontroller EC8, the 2 pin of the microcontroller EC7, the 2 pin of the microcontroller EC5, the 6 pin of the microcontroller EC8, the 1 pin of the resistor R8 and the 1 pin of the resistor R9 are grounded, the surface of the microcontroller EC4 is connected with the R phase output isolation transformer (4), the S phase output isolation transformer (5) and the T phase output isolation transformer (6) respectively.

3. The three-phase-to-single-phase full power output AC variable frequency power supply according to claim 1, characterized in that: The R-phase output isolation transformer (4) comprises a fuse F1, a triode Q1, a triode Q2, a triode Q3, a triode Q4, an R-phase IGBT drive, a transformer T1, a resistor R4, a capacitor C4, a capacitor C6, a capacitor C7 and a capacitor C1, the 2 terminal pins of the fuse F1 are connected with the 2 terminal pins of the triode Q1, one end of the capacitor C1 and the 2 terminal pins of the triode Q3 respectively, the 3 terminal pins of the triode Q1 are connected with the 2 terminal pins of the triode Q2 and the 3 terminal pin of the transformer T1 respectively, the 3 terminal pins of the triode Q3 are connected with the 2 terminal pins of the triode Q4 and the 4 terminal pin of the transformer T1 respectively, the 1 terminal pin of the triode Q1 and the 1 terminal pin of the triode Q2 are connected with one end of the R-phase IGBT drive, the 1 terminal pin of the transformer T1 is connected with the 1 terminal pin of the resistor R4, one end of the capacitor C6 and one end of the capacitor C7 respectively, the 2 terminal pin of the transformer T1 is connected with one end of the capacitor C4, the other end of the capacitor C6 and the other end of the capacitor C7 respectively, the 2 terminal pin of the resistor R4 is connected with the other end of the capacitor C4, the other end of the R-phase IGBT drive is connected with the mainboard (1).

4. The three-phase-to-single-phase full power output AC variable frequency power supply according to claim 1, characterized in that: The S-phase output isolation transformer (5) comprises a fuse F2, a triode Q5, a triode Q2, a triode Q7, a triode Q8, an S-phase IGBT drive, a transformer T2, a resistor R5, a capacitor C3, a capacitor C5, a capacitor C8 and a capacitor C2, the 2 terminal pins of the fuse F2 are connected with the 2 terminal pins of the triode Q5, one end of the capacitor C2 and the 2 terminal pins of the triode Q7 respectively, the 3 terminal pins of the triode Q5 are connected with the 2 terminal pins of the triode Q2 and the 3 terminal pin of the transformer T2 respectively, the 3 terminal pins of the triode Q7 are connected with the 2 terminal pins of the triode Q8 and the 4 terminal pin of the transformer T2 respectively, the 1 terminal pin of the triode Q5 and the 1 terminal pin of the triode Q2 are connected with one end of the S-phase IGBT drive, the 1 terminal pin of the transformer T2 is connected with the 1 terminal pin of the resistor R5, one end of the capacitor C5 and one end of the capacitor C8 respectively, the 2 terminal pin of the transformer T2 is connected with one end of the capacitor C3, the other end of the capacitor C5 and the other end of the capacitor C8 respectively, the 2 terminal pin of the resistor R5 is connected with the other end of the capacitor C3, the other end of the S-phase IGBT drive is connected with the mainboard (1).

5. The three-phase-to-single-phase full power output AC variable frequency power supply according to claim 1, characterized in that: The T-phase output isolation transformer (6) comprises a fuse F3, a triode Q9, a triode Q2, a triode Q11, a triode Q12, a T-phase IGBT drive, a transformer T3, a resistor R10, a capacitor C9, a capacitor C10, a capacitor C11 and a capacitor C15, the 2 terminal pins of the fuse F3 are connected with the 2 terminal pins of the triode Q9, one end of the capacitor C15 and the 2 terminal pins of the triode Q11 respectively, the 3 terminal pins of the triode Q9 are connected with the 2 terminal pins of the triode Q2 and the 3 terminal pins of the transformer T3 respectively, the 3 terminal pins of the triode Q11 are connected with the 2 terminal pins of the triode Q12 and the 4 terminal pins of the transformer T3 respectively, the 1 terminal pin of the triode Q9 and the 1 terminal pin of the triode Q2 are connected with one end of the T-phase IGBT drive, the 1 terminal pins of the transformer T3 are connected with the 1 terminal pin of the resistor R10, one end of the capacitor C10 and one end of the capacitor C11 respectively, the 2 terminal pins of the transformer T3 are connected with one end of the capacitor C9, the other end of the capacitor C10 and the other end of the capacitor C11 respectively, the 2 terminal pin of the resistor R10 is connected with the other end of the capacitor C9, and the other end of the T-phase IGBT drive is connected with the mainboard (1).

6. The three-phase-to-single-phase full power output AC variable frequency power supply according to claim 1, characterized in that: The three-turn single-interlock switching contactor (7) comprises a connector J11, a connector J12 and a connector J13, the 1 terminal pin of the connector J11 is connected with a J7-1 output T, the 1 terminal pin of the connector J12 is connected with a J5-1 output S, and the 1 terminal pin of the connector J13 is connected with a J4-1 output R, the 2 terminal pins of the connector J11 are connected with a transformer T4 and a current transformer CT3 respectively, the 2 terminal pin of the connector J12 is connected with a current transformer CT2, the 2 terminal pins of the connector J13 are connected with a transformer T5 and a current transformer CT1 respectively, the 2 terminal pin of the current transformer CT3 is connected with a transformer T6, the 2 terminal pin of the transformer T4, the 1 terminal pin of the transformer T5 and the 2 terminal pin of the transformer T6 are all connected with a capacitor CY, one end of the capacitor CY is connected with a switch S4, the 1 terminal pin of the switch S4 is grounded, and the 3 terminal pins of the connector J11, the connector J12 and the connector J13 are all connected with a J14-1.

7. The three-phase-to-single-phase full power output AC variable frequency power supply according to claim 1, characterized in that: The 1 terminal pin of the three-phase EMI filter (3) is connected with an input AJ1-1, the 2 terminal pin of the three-phase EMI filter (3) is connected with an input BJ2-1, the 3 terminal pin of the three-phase EMI filter (3) is connected with an input CJ6-1, the 4 terminal pin of the three-phase EMI filter (3) is connected with an input NJ10-1, and the 6 terminal pin of the three-phase EMI filter (3) is grounded.

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