Double-current-source parallel output system based on non-contact power supply system

Abstract

The invention discloses a double-current-source parallel output system based on a non-contact power supply system, which belongs to the technical field of power supplies and comprises a rectifying and filtering unit, a high-frequency transformer, a filtering unit, a PWM (Pulse Width Modulation) control unit, a PI (Proportional Integral) adjusting unit, a signal amplifying unit, a sampling unit, a touch screen and a reference voltage generating unit, the technical problem of improving the power supply efficiency, stability and current-sharing output performance of the WPS non-contact power supply system is solved, the transmission efficiency can be improved, meanwhile, higher power transmission is supported, the stability of electric energy transmission is improved, accurate control over the target current value is achieved, the response speed and the adjustment precision of the system are effectively improved, and the service life of the system is prolonged. The output stability and the power utilization efficiency of the system are improved, and the problem of current unbalance caused by load fluctuation is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of power supply, and in particular relates to a dual current source parallel output system based on a contactless power supply system. Background Art

[0002] WPS (Wireless Power Supply) non-contact power supply system is a power supply technology that realizes power transmission through the principle of electromagnetic coupling. Such systems usually consist of two parts: the power supply end (supplier) and the power consumption end (receiver). The power supply end generates a high-frequency electromagnetic field and transmits energy to the receiving end through electromagnetic coupling, thereby charging the battery or device or directly powering it. The advantages of the WPS non-contact power supply system include eliminating the wear problem of contact connection and good electrical isolation performance. It is widely used in consumer electronics, medical equipment, industrial equipment and other fields.

[0003] Existing disadvantages of WPS contactless power supply system:

[0004] Although WPS technology is highly secure and convenient, it still faces many challenges in terms of power transmission stability, energy loss control, and multiple load current sharing output:

[0005] 1. The stability of the power supply output: In the existing WPS system, the power supply mostly adopts a single current source design, which makes it susceptible to load changes during the contactless transmission process. Especially when the power supply fluctuates or the load is large, the stability of the output current cannot be guaranteed, and uneven power supply or voltage output deviation is prone to occur.

[0006] 2. Lack of precise current control and regulation mechanism: Traditional power supplies usually use simple control circuits, which cannot accurately regulate the output current or provide stable output current. Existing systems rarely integrate precise regulation modules such as PI controllers, making it difficult to achieve dynamic regulation of the output, especially lack of stability control when power demand changes.

[0007] 3. Lack of current sharing control and protection: Existing power supply designs generally lack parallel current sharing control, and cannot achieve effective coordinated output of multiple current sources. Even if some systems use dual current source output solutions, they lack effective current sharing control strategies, which can easily lead to unbalanced output current due to load fluctuations, thereby reducing the overall efficiency and stability of the system. Summary of the invention

[0008] The purpose of the present invention is to provide a dual current source parallel output system based on a contactless power supply system, which solves the technical problems of improving the power supply efficiency, stability and current equalization output performance of the WPS contactless power supply system.

[0009] To achieve the above object, the present invention adopts the following technical solution:

[0010] A dual current source parallel output system based on a contactless power supply system includes a rectifier filter unit, a high-frequency transformer, a filter unit, a PWM control unit, a PI adjustment unit, a signal amplification unit, a sampling unit, a touch screen and a reference voltage generation unit. The input end of the rectifier unit is connected to an external AC power supply, and the output end is connected to the primary side of the high-frequency transformer. The secondary side of the high-frequency transformer is connected to the input end of the filter unit. The output end of the filter unit outputs a constant current source I out ;

[0011] The input end of the sampling unit is connected to the output end of the filtering unit, and the output end is connected to the input end of the signal amplifying unit, and the output end of the signal amplifying unit is connected to an AD input end of the PI regulating unit;

[0012] The touch screen is connected to the reference voltage generating unit, the reference voltage generating unit is connected to the PI regulating unit, the control signal output end of the PI regulating unit is connected to the control input end of the PWM control unit, and the PWM output end of the PWM control unit is connected to the control end of the rectifier unit;

[0013] The rectifier unit specifically adopts a double-tube forward converter circuit, and output control is performed by controlling the alternating operation of two IGBT tubes in the double-tube forward converter circuit;

[0014] The PI adjustment unit calculates the duty cycle u(t) of the PWM signal through the PI control algorithm, and performs the current sharing error calculation at the same time. On the basis of the duty cycle u(t), the adjustment factors D21 and D22 are added to realize the phase-to-phase current sharing control calculation and generate the current sharing control signal.

[0015] The PWM control unit receives the current sharing control signal from the PI regulation unit, generates a PWM control signal according to the current sharing control signal, and controls the two IGBT tubes in the rectifier unit;

[0016] The reference voltage generating unit is used to generate reference current data according to the parameters input by the touch screen, and transmit the reference current data to the PI regulating unit through the UART interface.

[0017] Preferably, the filtering unit comprises an IGBT tube Q1, an IGBT tube Q2, a diode D1 and a diode D3, the G pole of the IGBT tube Q1 and the G pole of the IGBT tube Q2 constitute the control end of the rectifier unit, the C pole of the IGBT tube Q1 and the cathode of the diode D1 are connected to an external AC power supply, the E pole of the IGBT tube Q1 is connected to the cathode of the diode D1, the cathode of the diode D3 and the E pole of the IGBT tube Q2 are connected to the external AC power supply, and the anode of the diode D3 is connected to the C pole of the IGBT tube Q2;

[0018] The high-frequency transformer is transformer T1, one end of the primary side of transformer T1 is connected to the E pole of IGBT tube Q1, and the other end is connected to the C pole of IGBT tube Q2;

[0019] The filter unit includes a diode D5, a diode D6, an inductor L1 and a capacitor C1. The anode of the diode D5 is the input terminal of the filter unit. One end of the secondary side of the transformer T1 outputs a ground wire and the other end is connected to the anode of the diode D5. The cathode of the diode D5 is connected to the 1st pin of the inductor L1. The 2nd pin of the inductor L1 outputs a constant current source I out , the positive electrode of the diode D6 is connected to the ground wire, and the negative electrode is connected to the negative electrode of the diode D5, the 2nd foot of the inductor L1 is the output end of the filter unit, one end of the capacitor C1 is connected to the 2nd foot of the inductor L1, and the other end is connected to the ground wire;

[0020] The sampling unit includes a sampling resistor R4, which is connected in series with a constant current source I out On, used for constant current source I out The current is sampled.

[0021] Preferably, the signal amplification unit is composed of an amplifier A1 and its peripheral circuits, the model of the amplifier A1 is AD623, and the differential input terminals of the amplifier are respectively connected to the two ends of the sampling resistor R4;

[0022] The PI adjustment unit includes a single-chip microcomputer MCU1 and its peripheral circuits. The model of the single-chip microcomputer MCU1 is STM32F030C8T6. The output end of the amplifier A1 is connected to an AD interface AD1 of the single-chip microcomputer MCU1.

[0023] Preferably, the PWM control unit includes a PWM controller IC1, the model of the PWM controller IC1 is NIS6602, the INA terminal, INB terminal and DIS terminal of the PWM controller IC1 constitute the control input terminal of the PWM control unit, and a group of IO ports of the single-chip microcomputer MCU1 are respectively connected to the INA terminal, INB terminal and DIS terminal, and the group of IO ports constitute the control signal output terminal of the PI adjustment unit;

[0024] The OUTA terminal and the OUTB terminal of the PWM controller IC1 constitute the PWM output terminal of the PWM control unit, and the OUTA terminal and the OUTB terminal are connected to the G pole of the IGBT tube Q1 and the G pole of the IGBT tube Q2 respectively.

[0025] Preferably, the reference voltage generating unit comprises a single chip microcomputer MCU2, the model of the single chip microcomputer MCU2 is STM32F103C8T6, the single chip microcomputer MCU2 is connected to the touch screen via a serial port, and a UART interface port of the single chip microcomputer MCU2 is connected to a UART interface port of the single chip microcomputer MCU1.

[0026] Preferably, the specific formula for calculating the duty cycle u(t) of the PWM signal using the PI control algorithm is as follows:

[0027] u(t)=K p ·e(t)+K i ∫e(t)dt;

[0028] e(t)=Is-I measured ;

[0029] Where e(t) represents the reference current Is and the measured current I measured The error between measured The value of I 1 or I 2 , I 1 is the sampling current when the IGBT tube Q1 is turned on, I 2 is the sampling current when the IGBT tube Q2 is turned on, K p is the proportionality coefficient, K i is the integration coefficient;

[0030] The reference current Is is obtained from the reference current data input by the user through the touch screen;

[0031] When I measured =I 1 When , the duty cycle u(t) controls the on-time and off-time of the IGBT tube Q1, affecting the phase shift angle of the IGBT tube Q1. The duty cycle u(t) at this time is used as an influencing parameter to participate in the current sharing error calculation, which is recorded as D21;

[0032] When I measured =I 2 When , the duty cycle u(t) controls the on-time and off-time of the IGBT tube Q2, affecting the phase shift angle of the IGBT tube Q2. The duty cycle u(t) at this time is used as an influencing parameter to participate in the current sharing error calculation, which is recorded as D22;

[0033] The specific formula for calculating the current sharing error is as follows:

[0034] Judgment condition: current ratio I 1 ÷I 2 Judgment: If (I 1 ÷I 2 )>1, then D22=D21+ΔD, otherwise, D22=D21-ΔD;

[0035] I 1 is the sampling current when the IGBT tube Q1 is turned on, I 2 is the sampling current when the IGBT tube Q2 is turned on, ΔD is the adjustment value of the phase shift angle influencing parameter; D21 is the basic phase shift angle of the IGBT tube Q1, and D22 is the basic phase shift angle of the IGBT tube Q2;

[0036]

[0037] Wherein, D1 is the phase shift angle influencing parameter of the reference current, which is used as the reference for adjusting the phase shift angle during the current sharing control process. The preset value of D1 is calculated according to the following formula;

[0038] D1=k×Is+b;

[0039] Among them, k is the scale factor and b is the offset.

[0040] The dual current source parallel output system based on the contactless power supply system described in the present invention solves the technical problems of improving the power supply efficiency, stability and current-balanced output performance of the WPS contactless power supply system. The present invention adopts a dual-tube forward conversion circuit design. The dual-switch tube structure (Q1, Q2) transmits electric energy through coupling with a high-frequency transformer, which can improve transmission efficiency and support higher power transmission. Compared with the single-switch tube structure, the dual-tube forward circuit can reduce switch stress, reduce voltage fluctuations, and improve the stability of power transmission. It integrates a PI controller module, which is processed by a single-chip microcomputer. By sampling the feedback current signal and the current reference signal, the output current of the supply is dynamically adjusted to achieve precise control of the target current value. This closed-loop control method overcomes the problem of slow response of traditional power supplies to load changes, effectively improves the system response speed and regulation accuracy, introduces a two-phase current sharing control algorithm, can achieve load balancing between dual current sources, improves the system's output stability and power utilization efficiency, avoids the current imbalance problem caused by load fluctuations, and ensures the stable current output of the power supply under different loads. The NSI6602 chip is used to generate PWM signals, and the duty cycle of the IGBT tube is flexibly adjusted according to the compensation signal u(t) output by the PI controller, thereby controlling the on-off time of the switch tube and adjusting the output power. This ensures the flexibility of the system under different power requirements, while improving conversion efficiency and response speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic block diagram of the present invention;

[0042] Figure 2 It is a circuit diagram of the rectification and filtering unit, the high-frequency transformer, the filtering unit and the sampling unit of the present invention;

[0043] Figure 3 It is a schematic diagram of the principle diagram interface of the PWM control unit, PI adjustment unit, signal amplification unit, touch screen and reference voltage generation unit of the present invention. DETAILED DESCRIPTION

[0044] like Figure 1-Figure 3A dual current source parallel output system based on a contactless power supply system is shown, comprising a rectifier filter unit, a high-frequency transformer, a filter unit, a PWM control unit, a PI adjustment unit, a signal amplification unit, a sampling unit, a touch screen and a reference voltage generation unit, wherein the input end of the rectifier unit is connected to an external AC power supply, the output end is connected to the primary side of the high-frequency transformer, the secondary side of the high-frequency transformer is connected to the input end of the filter unit, and the output end of the filter unit outputs a constant current source I out ;

[0045] The rectifier unit specifically adopts a double-tube forward converter circuit, and output control is performed by controlling the alternating operation of two IGBT tubes in the double-tube forward converter circuit.

[0046] The filtering unit includes an IGBT tube Q1, an IGBT tube Q2, a diode D1 and a diode D3, wherein the G pole of the IGBT tube Q1 and the G pole of the IGBT tube Q2 constitute the control end of the rectifier unit, the C pole of the IGBT tube Q1 and the cathode of the diode D1 are connected to an external AC power supply, the E pole of the IGBT tube Q1 is connected to the cathode of the diode D1, the cathode of the diode D3 and the E pole of the IGBT tube Q2 are connected to the external AC power supply, and the anode of the diode D3 is connected to the C pole of the IGBT tube Q2;

[0047] The high-frequency transformer is transformer T1, one end of the primary side of the transformer secondary T1 is connected to the E pole of the IGBT tube Q1, and the other end is connected to the C pole of the IGBT tube Q2;

[0048] The filter unit includes a diode D5, a diode D6, an inductor L1 and a capacitor C1. The anode of the diode D5 is the input terminal of the filter unit. One end of the secondary side of the transformer T1 outputs a ground wire and the other end is connected to the anode of the diode D5. The cathode of the diode D5 is connected to the 1st pin of the inductor L1. The 2nd pin of the inductor L1 outputs a constant current source I out , the positive electrode of the diode D6 is connected to the ground wire, and the negative electrode is connected to the negative electrode of the diode D5, the 2nd foot of the inductor L1 is the output end of the filter unit, one end of the capacitor C1 is connected to the 2nd foot of the inductor L1, and the other end is connected to the ground wire;

[0049] The input end of the sampling unit is connected to the output end of the filtering unit, and the output end is connected to the input end of the signal amplifying unit, and the output end of the signal amplifying unit is connected to an AD input end of the PI regulating unit;

[0050] The sampling unit includes a sampling resistor R4, which is connected in series with a constant current source I out On, used for constant current source I out The current is sampled.

[0051] The signal amplification unit is composed of an amplifier A1 and its peripheral circuits. The model of the amplifier A1 is AD623. The differential input terminals of the amplifier are respectively connected to the two ends of the sampling resistor R4.

[0052] The PI adjustment unit includes a single-chip microcomputer MCU1 and its peripheral circuits. The model of the single-chip microcomputer MCU1 is STM32F030C8T6. The output end of the amplifier A1 is connected to an AD interface AD1 of the single-chip microcomputer MCU1.

[0053] The PI regulation unit calculates the duty cycle u(t) of the PWM signal through the PI control algorithm, and performs current sharing error calculation at the same time. On the basis of the duty cycle u(t), the regulation factors D21 and D22 are added to realize the phase-to-phase current sharing control calculation and generate a current sharing control signal.

[0054] The specific formula for calculating the duty cycle u(t) of the PWM signal using the PI control algorithm is as follows:

[0055] u(t)=K p ·e(t)+K i ∫e(t)dt;

[0056] e(t)=Is-I measured ;

[0057] Where e(t) represents the reference current Is and the measured current I measured The error between measured The value of I 1 or I 2 , I 1 is the sampling current when the IGBT tube Q1 is turned on, I 2 is the sampling current when the IGBT tube Q2 is turned on, K p is the proportionality coefficient, K i is the integration coefficient;

[0058] The reference current Is is obtained from the reference current data input by the user through the touch screen;

[0059] When I measured =I 1 When , the duty cycle u(t) controls the on-time and off-time of the IGBT tube Q1, affecting the phase shift angle of the IGBT tube Q1. The duty cycle u(t) at this time is used as an influencing parameter to participate in the current sharing error calculation, which is recorded as D21;

[0060] When I measured =I 2 When , the duty cycle u(t) controls the on-time and off-time of the IGBT tube Q2, affecting the phase shift angle of the IGBT tube Q2. The duty cycle u(t) at this time is used as an influencing parameter to participate in the current sharing error calculation, which is recorded as D22;

[0061] The specific formula for calculating the current sharing error is as follows:

[0062] Judgment condition: current ratio I 1 ÷I 2 Judgment: If (I 1 ÷I 2 )>1, then D22=D21+ΔD, otherwise, D22=D21-ΔD;

[0063] I 1 is the sampling current when the IGBT tube Q1 is turned on, I 2 is the sampling current when the IGBT tube Q2 is turned on, ΔD is the adjustment value of the phase shift angle influencing parameter; D21 is the basic phase shift angle of the IGBT tube Q1, and D22 is the basic phase shift angle of the IGBT tube Q2;

[0064]

[0065] Wherein, D1 is the phase shift angle influencing parameter of the reference current, which is used as the reference for adjusting the phase shift angle during the current sharing control process. The preset value of D1 is calculated according to the following formula;

[0066] D1=k×Is+b;

[0067] Among them, k is the scale factor and b is the offset.

[0068] The touch screen is connected to the reference voltage generating unit, the reference voltage generating unit is connected to the PI regulating unit, the control signal output end of the PI regulating unit is connected to the control input end of the PWM control unit, and the PWM output end of the PWM control unit is connected to the control end of the rectifier unit;

[0069] The PWM control unit includes a PWM controller IC1, the model of the PWM controller IC1 is NIS6602, the INA terminal, INB terminal and DIS terminal of the PWM controller IC1 constitute the control input terminal of the PWM control unit, and a group of IO ports of the single-chip microcomputer MCU1 are respectively connected to the INA terminal, INB terminal and DIS terminal, and the group of IO ports constitute the control signal output terminal of the PI adjustment unit;

[0070] The OUTA terminal and the OUTB terminal of the PWM controller IC1 constitute the PWM output terminal of the PWM control unit, and the OUTA terminal and the OUTB terminal are connected to the G pole of the IGBT tube Q1 and the G pole of the IGBT tube Q2 respectively.

[0071] The PWM control unit receives the current sharing control signal from the PI regulation unit, generates a PWM control signal according to the current sharing control signal, and controls the two IGBT tubes in the rectifier unit.

[0072] The reference voltage generating unit comprises a single chip microcomputer MCU2, the model of the single chip microcomputer MCU2 is STM32F103C8T6, the single chip microcomputer MCU2 is connected to the touch screen via a serial port, and a UART interface port of the single chip microcomputer MCU2 is connected to a UART interface port of the single chip microcomputer MCU1.

[0073] The reference voltage generating unit is used to generate reference current data according to the parameters input by the touch screen, and transmit the reference current data to the PI regulating unit through the UART interface.

[0074] A specific application step of this embodiment is as follows:

[0075] Step 1: After the system is powered on, the microcontroller MCU1 initializes each unit, including setting the initial parameters of ADC and PWM control.

[0076] Step 2: The user sets the target current value (reference current Is) through the touch screen. This information is transmitted to MCU2, and MCU2 outputs it to MCU1 through the UART interface for subsequent PI control calculations.

[0077] Step 3: The sampling resistor R4 is placed at the output end of the filter unit to measure the output current Iout; the amplifier AD623 amplifies the signal at both ends of the sampling resistor R4 and outputs it to MCU1, which calculates the sampling current value through Ohm's law;

[0078] The system collects current values ​​I1 and I2 during the switching of Q1 and Q2 respectively;

[0079] Step 4: In the PI control unit, use the PI control algorithm to calculate the duty cycle u(t) of the PWM signal, and use the u(t) calculation formula and the sampling current I when the IGBT tube Q1 is turned on. 1 , the sampling current I when the IGBT tube Q2 is turned on 2 , calculate the influencing parameter D21 and the influencing parameter D22 respectively;

[0080] Step 5: Calculate the current sharing error and set the judgment condition, that is, the current ratio I 1 ÷I 2 Judgment: If (I 1 ÷I 2 )>1, then D22=D21+ΔD, otherwise, D22=D21-ΔD; finally, the phase shift angle influencing parameter D21 of the IGBT tube Q1 and the phase shift angle influencing parameter D22 of the IGBT tube Q2 are updated, and the corresponding current sharing control signal is generated according to the updated D21 and D22;

[0081] Step 6: MCU2 controls PWM controller IC1 (NIS6602) according to the current sharing control signal. PWM controller IC1 generates a PWM control signal to control the actions of Q1 and Q2 to achieve precise control of the target current value.

[0082] The dual current source parallel output system based on the contactless power supply system described in the present invention solves the technical problems of improving the power supply efficiency, stability and current-balanced output performance of the WPS contactless power supply system. The present invention adopts a dual-tube forward conversion circuit design. The dual-switch tube structure (Q1, Q2) transmits electric energy through coupling with a high-frequency transformer, which can improve the transmission efficiency and support higher power transmission. Compared with the single-switch tube structure, the dual-tube forward circuit can reduce switch stress, reduce voltage fluctuations, and improve the stability of power transmission. The integrated PI controller module is processed by a single-chip microcomputer, and the output current of the supply is dynamically adjusted by sampling the feedback current signal and the current reference signal to achieve accurate control of the target current value. This closed-loop control method overcomes the problem of slow response of traditional power supplies to load changes, effectively improves the system response speed and regulation accuracy, introduces a two-phase current sharing control algorithm, can achieve load balancing between dual current sources, improve the system's output stability and power utilization efficiency, avoids the current imbalance problem caused by load fluctuations, and ensures the stable current output of the power supply under different loads. The NSI6602 chip is used to generate PWM signals, and the duty cycle of the IGBT tube is flexibly adjusted according to the compensation signal u(t) output by the PI controller, thereby controlling the on-off time of the switch tube and adjusting the output power. This ensures the flexibility of the system under different power requirements, while improving conversion efficiency and response speed.

Claims

1. A dual current source parallel output system based on a contactless power supply system, characterized in that: The invention comprises a rectifier filter unit, a high-frequency transformer, a filter unit, a PWM control unit, a PI adjustment unit, a signal amplification unit, a sampling unit, a touch screen and a reference voltage generation unit. The input end of the rectifier unit is connected to an external AC power supply, and the output end is connected to the primary side of the high-frequency transformer. The secondary side of the high-frequency transformer is connected to the input end of the filter unit. The output end of the filter unit outputs a constant current source I out ; The input end of the sampling unit is connected to the output end of the filtering unit, and the output end is connected to the input end of the signal amplifying unit, and the output end of the signal amplifying unit is connected to an AD input end of the PI regulating unit; The touch screen is connected to the reference voltage generating unit, the reference voltage generating unit is connected to the PI regulating unit, the control signal output end of the PI regulating unit is connected to the control input end of the PWM control unit, and the PWM output end of the PWM control unit is connected to the control end of the rectifier unit; The rectifier unit specifically adopts a double-tube forward converter circuit, and output control is performed by controlling the alternating operation of two IGBT tubes in the double-tube forward converter circuit; The PI adjustment unit calculates the duty cycle u(t) of the PWM signal through the PI control algorithm, and performs the current sharing error calculation at the same time, and finally obtains the phase shift angle influence parameter D21 and the phase shift angle influence parameter D22, realizes the phase-to-phase current sharing control calculation, and generates the current sharing control signal; The PWM control unit receives the current sharing control signal from the PI regulation unit, generates a PWM control signal according to the current sharing control signal, and controls the two IGBT tubes in the rectifier unit; The reference voltage generating unit is used to generate reference current data according to the parameters input by the touch screen, and transmit the reference current data to the PI regulating unit through the UART interface.

2. A dual current source parallel output system based on a contactless power supply system as claimed in claim 1, characterized in that: The filtering unit includes an IGBT tube Q1, an IGBT tube Q2, a diode D1 and a diode D3, wherein the G pole of the IGBT tube Q1 and the G pole of the IGBT tube Q2 constitute the control end of the rectifier unit, the C pole of the IGBT tube Q1 and the cathode of the diode D1 are connected to an external AC power supply, the E pole of the IGBT tube Q1 is connected to the cathode of the diode D1, the cathode of the diode D3 and the E pole of the IGBT tube Q2 are connected to the external AC power supply, and the anode of the diode D3 is connected to the C pole of the IGBT tube Q2; The high-frequency transformer is transformer T1, one end of the primary side of transformer T1 is connected to the E pole of IGBT tube Q1, and the other end is connected to the C pole of IGBT tube Q2; The filter unit includes a diode D5, a diode D6, an inductor L1 and a capacitor C1. The anode of the diode D5 is the input terminal of the filter unit. One end of the secondary side of the transformer T1 outputs a ground wire and the other end is connected to the anode of the diode D5. The cathode of the diode D5 is connected to the 1st pin of the inductor L1. The 2nd pin of the inductor L1 outputs a constant current source I out , the positive electrode of the diode D6 is connected to the ground wire, and the negative electrode is connected to the negative electrode of the diode D5, the 2nd foot of the inductor L1 is the output end of the filter unit, one end of the capacitor C1 is connected to the 2nd foot of the inductor L1, and the other end is connected to the ground wire; The sampling unit includes a sampling resistor R4, which is connected in series with a constant current source I out On, used for constant current source I out The current is sampled.

3. A dual current source parallel output system based on a contactless power supply system as claimed in claim 2, characterized in that: The signal amplification unit is composed of an amplifier A1 and its peripheral circuits. The model of the amplifier A1 is AD623. The differential input terminals of the amplifier are respectively connected to the two ends of the sampling resistor R4. The PI adjustment unit includes a single-chip microcomputer MCU1 and its peripheral circuits. The model of the single-chip microcomputer MCU1 is STM32F030C8T6. The output end of the amplifier A1 is connected to an AD interface AD1 of the single-chip microcomputer MCU1.

4. A dual current source parallel output system based on a contactless power supply system as claimed in claim 3, characterized in that: The PWM control unit includes a PWM controller IC1, the model of the PWM controller IC1 is NIS6602, the INA terminal, INB terminal and DIS terminal of the PWM controller IC1 constitute the control input terminal of the PWM control unit, and a group of IO ports of the single-chip microcomputer MCU1 are respectively connected to the INA terminal, INB terminal and DIS terminal, and the group of IO ports constitute the control signal output terminal of the PI adjustment unit; The OUTA terminal and the OUTB terminal of the PWM controller IC1 constitute the PWM output terminal of the PWM control unit, and the OUTA terminal and the OUTB terminal are connected to the G pole of the IGBT tube Q1 and the G pole of the IGBT tube Q2 respectively.

5. A dual current source parallel output system based on a contactless power supply system as claimed in claim 3, characterized in that: The reference voltage generating unit comprises a single chip microcomputer MCU2, the model of the single chip microcomputer MCU2 is STM32F103C8T6, the single chip microcomputer MCU2 is connected to the touch screen via a serial port, and a UART interface port of the single chip microcomputer MCU2 is connected to a UART interface port of the single chip microcomputer MCU1.

6. A dual current source parallel output system based on a contactless power supply system as claimed in claim 1, characterized in that: The specific formula for calculating the duty cycle u(t) of the PWM signal using the PI control algorithm is as follows: u(t)=K p ·e(t)+K i ∫e(t)dt; e(t)=Is-I measured ; Where e(t) represents the reference current Is and the measured current I measured The error between measured The value of is I1 or I2, I1 is the sampling current when the IGBT tube Q1 is turned on, I2 is the sampling current when the IGBT tube Q2 is turned on, K p is the proportionality coefficient, K i is the integration coefficient; The reference current Is is obtained from the reference current data input by the user through the touch screen; When I measured =I1, the duty cycle u(t) controls the on-time and off-time of the IGBT tube Q1, affecting the phase shift angle of the IGBT tube Q1. The duty cycle u(t) at this time is used as an influencing parameter to participate in the current sharing error calculation, which is recorded as D21; When I measured =I2, the duty cycle u(t) controls the on-time and off-time of the IGBT tube Q2, affecting the phase shift angle of the IGBT tube Q2. The duty cycle u(t) at this time is used as an influencing parameter to participate in the current sharing error calculation, which is recorded as D22; The specific formula for calculating the current sharing error is as follows: Judgment condition: current ratio I1÷I2 judgment: if (I1÷I2)>1, then D22=D21+ΔD, otherwise, D22=D21-ΔD; I1 is the sampling current when the IGBT tube Q1 is turned on, I2 is the sampling current when the IGBT tube Q2 is turned on, ΔD is the adjustment value of the phase shift angle influencing parameter; D21 is the basic phase shift angle of the IGBT tube Q1, and D22 is the basic phase shift angle of the IGBT tube Q2; Wherein, D1 is the phase shift angle influencing parameter of the reference current, which is used as the reference for adjusting the phase shift angle during the current sharing control process. The preset value of D1 is calculated according to the following formula; D1=k×Is+b; Among them, k is the scale factor and b is the offset.

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