CN117477803A - Inversion resonance constant-power wireless charging system and control method - Google Patents

Abstract

This application relates to an inverter resonant constant power wireless charging system and a control method. The system includes: a transmitting end and a receiving end; the transmitting end includes: a transmitting power module, a high-frequency full-bridge inverter circuit, an LCC power compensation module, a transmitting coil, a main control module and bus voltage and current measurement module; the receiving end includes: receiving coil, symmetrical LCC power compensation circuit, rectifier module, synchronous Buck circuit, overvoltage protection circuit, supercapacitor group, capacitor voltage measurement module, charging current and resonance voltage measurement module ;The transmitting coil transmits power to the receiving coil through magnetic coupling resonance. The system of this invention can adjust the impedance of the receiving end in real time by accurately matching the reflection resistance of the receiving end and combining it with the synchronous Buck circuit, so that the load end can maintain high efficiency and constant power without changing the output power at the transmitting end and the impedance of the energy storage device at the receiving end changes. Charge.

Description

Inverter resonant constant power wireless charging system and control method

Technical field

The present application relates to the field of wireless charging technology, and in particular to an inverter resonant constant power wireless charging system and control method.

Background technique

Many service robots such as driverless express delivery vehicles and food delivery still use infrared positioning solutions. That is, the robot's charging base continuously sends out infrared signals, and the robot's infrared signal receiver receives the number and location of the signals. to determine your own position and then plan a route back to the charging pile. This solution requires that the robot cannot be used in complex walls or long distances. For robots with a charging power of 300-400W, the non-hard-pluggable wireless charging base has safety risks such as high heat and short circuit. On the transmitter end: In the face of low power conditions, some research results use PWM wave complementary phase shift control to achieve upper and lower limit control of power. However, this solution cannot achieve power closed loop, and there will be overshoot in the case of high power output. risks, and the inability to achieve high energy utilization under most conditions. For the receiving end: the common solution is to use LC series direct charge and LCC power compensation solution. If you want to maintain a high receiving efficiency, extremely precise mutual inductance values, impedance values, reflection resistance values, etc. are required for both solutions. In practice, In use, these values are difficult to control or measure, so the above two solutions are less robust in practical applications.

The structure of the existing technology is complex, and a bridge measurement circuit needs to be set up to measure the mutual inductance value to change the phase difference of the PWM wave at the transmitter end, that is, by changing the power at the transmitter end in real time to achieve constant received power at the load end. The implementation cost of this solution is high, and when the transmitter is in a high-power output state, the power loss is large and the temperature rise is large. When the load impedance increases, more transmit power is required to maintain constant power at the receiver, and energy utilization rate is lower.

Contents of the invention

Based on this, it is necessary to provide an inverter resonant constant power wireless charging system and control method to address the above technical problems.

An inverter resonant constant power wireless charging system and control method, the system includes: a transmitting end and a receiving end.

The transmitting end includes: a transmitting power module, a high-frequency full-bridge inverter circuit, an LCC power compensation module, a transmitting coil, a main control module and a bus voltage and current measurement module; the power module is connected to the input end of the high-frequency full-bridge inverter circuit. , the output end of the high-frequency full-bridge inverter circuit is connected to the LCC power compensation module, and the LCC power compensation module is connected to the transmitting coil; the bus voltage and current measurement module is used to measure the bus of the transmit power module voltage and current and transmit them to the main control module;

The receiving end includes: a receiving coil, a symmetrical LCC power compensation circuit, a rectifier module, a synchronous Buck circuit, an overvoltage protection circuit, a supercapacitor group, a capacitor voltage measurement module, and a charging current and resonance voltage measurement module.

The transmitting coil transmits power to the receiving coil through magnetic coupling resonance; the receiving coil is connected to the rectifier module through the symmetrical LCC power compensation circuit, and the rectifier module is connected to the input end of the synchronous Buck circuit connection, the output end of the synchronous Buck circuit is connected to the supercapacitor group through the overvoltage protection circuit; the charging current and resonance voltage measurement module is used to measure the voltage and current values of the signal output by the rectifier module, and transmit to the main control module; the capacitance voltage measurement module is used to measure the capacitance voltage of the supercapacitor group and transmit it to the main control module.

The main control module determines the real-time charging power based on the charging current and resonant voltage measured by the charging current and resonant voltage measurement module, and outputs two first PWM signals to the high-frequency full bridge based on the real-time charging power and the preset constant power. The inverter circuit adjusts the transmit power and simultaneously outputs two second PWM signals to the synchronous Buck circuit for charging power adjustment to complete constant power wireless charging.

In one embodiment, the main control module includes a domestic microcontroller with Risc-v architecture.

In one embodiment, the high-frequency full-bridge inverter circuit includes: two high-frequency half-bridge gate drivers and a high-frequency full-bridge inverter.

The input terminals of the two high-frequency half-bridge gate drivers are connected to the main control module, and the two output terminals of the first high-frequency half-bridge gate driver are respectively connected to the high-frequency full-bridge inverter. The gates of the two MOS transistors of the first half-bridge are connected, and the two output terminals of the second high-frequency half-bridge gate driver are respectively connected to the two MOS transistors of the second half-bridge of the high-frequency full-bridge inverter. The gates are connected, and the output terminals of the first half-bridge and the second half-bridge of the high-frequency full-bridge inverter are respectively connected to the two input terminals of the LCC power compensation module.

In one embodiment, the synchronous Buck circuit includes: a half-bridge drive module, a MOS half-bridge, and a filter module.

The two input terminals of the half-bridge drive module are connected to the main control module, and the two output terminals of the half-bridge drive module are respectively connected to the gates of the MOS tubes of the upper arm and the lower arm of the MOS half bridge. poles are connected, the source of the MOS on the upper arm of the MOS half bridge is connected to the drain of the MOS on the lower arm of the MOS half bridge, and the source of the MOS on the lower arm of the MOS half bridge is connected with the drain of the MOS on the lower arm of the MOS half bridge. One input terminal of the filter module is connected, the drain of the MOS of the lower arm of the MOS half bridge is connected to the other input terminal of the filter module, and the output terminal of the filter module is connected to the overvoltage protection circuit. .

In one embodiment, at the transmitting end, the main control module is also used to determine whether the transmitting power module is in a normal state based on the bus current and bus voltage of the transmitting power module measured by the bus voltage and current measurement module. If the state Normally, the ladder power control method is used to output the first PWM signal to the high-frequency full-bridge inverter circuit to control the high-frequency full-bridge inverter circuit; the ladder power control method is: linear regulation of 50% in 0.0s-1.0s -100% target power, linearly adjust 100% target power after 1.0s.

In one embodiment, the main control module is also used to protect the transmitter from overcurrent; the transmitter overcurrent protection refers to reading the bus current value measured by the bus voltage and current measurement module at a predetermined frequency. , obtain the current sample value and store it in the predetermined buffer array. Use the Butterworth low-pass filter to filter the current sample value, and then count a predetermined number of current data in the predetermined buffer array, and count them within 1 second. For the linear correlation coefficient and peak difference of all current data, set the weighted coefficient of the linear correlation coefficient and the peak difference. If the weighted sum of the linear correlation coefficient and the peak difference exceeds the preset threshold, there is overcurrent in the current system, and the main control module Stop outputting the first PWM signal and turn off the MOS tube of the high-frequency full-bridge inverter circuit.

In one embodiment, the main control module is also used to protect the receiving end from receiving overcurrent; the receiving overcurrent protection means: when the voltage difference on both sides of the receiving coil is less than a preset voltage difference threshold, then Set the charge and discharge current to the preset value; when the voltage difference on both sides of the receiving coil is greater than the preset voltage difference threshold, the charge and discharge current is limited. The current calculation formula is:

;

in, is the maximum charging current allowed by the current capacitor,/> is the capacitor voltage (real-time measurement),/> is the input voltage (after rectification),/> It is the maximum current allowed by MOS.

In one embodiment, the main control module is also used to perform hardware self-test on the receiving end circuit and perform running fault detection on the transmitting end and receiving end; wherein the running fault detection includes: over- and under-voltage anomalies, Overcurrent, abnormal charging and discharging.

The process of hardware self-test for the receiving end circuit includes: detecting the receiving end voltage and current within the preset time period after the start of transmission, storing them in predetermined buffer arrays respectively, filtering out white noise through low-pass filtering, and linearly changing the upper and lower two For the duty cycle of the MOS tube, calculate the voltage change rate, duty cycle change rate and current change rate based on the voltage and current data. If the voltage change rate is less than the duty cycle change rate, the MOS tube is determined to be damaged. If the voltage change rate If the ratio to the duty cycle change rate is greater than the upper limit of the threshold, and the current change rate is less than the lower limit of the current change rate threshold, it is concluded that the inductor is damaged;

The method for judging abnormal charging and discharging is: if the difference between the DC-DC set power and the actual calculated power is greater than the preset value for a long time, abnormal charging and discharging will occur.

The charging and discharging abnormality judgment method is: if the difference between the DC-DC set power and the actual calculated power is greater than the preset value for a long time, it is considered that a charging and discharging abnormality has occurred.

In one embodiment, the main control module is also used to adjust the output voltage of the synchronous Buck circuit according to the collected capacitance voltage of the supercapacitor group measured by the capacitance voltage measurement module, so that the supercapacitors in the supercapacitor group are not in the same state. Constant power charging in case of breakdown.

An inverter resonance constant power wireless charging control method, which is applied to any of the above inverter resonance constant power wireless charging systems to achieve constant power wireless charging; the method includes:

The main control module receives the bus voltage and bus current value of the transmitting power supply measured by the bus voltage and current measurement module, and determines whether the transmitting power supply can normally provide electric energy based on the bus voltage and the bus current value.

When the transmitting power source can provide normal power:

The main control module determines the real-time charging power based on the charging current and resonant voltage measured by the received current and resonant voltage measurement module, and outputs two first PWM signals to the high-frequency full-bridge inverter based on the real-time charging power and the preset constant power. Variable circuit to adjust transmit power.

When the transmitting power source can provide normal power:

The main control module determines the real-time charging power based on the received charging current and the resonant voltage measured by the resonant voltage measurement module, and outputs two first PWM signals to the high-frequency full bridge based on the real-time charging power and the preset constant power. The inverter circuit adjusts the transmit power.

When the main control module receives the capacitor voltage value of the supercapacitor group measured by the capacitor voltage measurement module, it outputs two second PWM signals to the synchronous Buck circuit for charging power adjustment to complete constant power wireless charging.

The above-mentioned inverter resonant constant power wireless charging system and control method include: a transmitting end and a receiving end; the transmitting end includes: a transmitting power module, a high-frequency full-bridge inverter circuit, an LCC power compensation module, a transmitting coil, a main control module and a busbar Voltage and current measurement module; the receiving end includes: receiving coil, symmetrical LCC power compensation circuit, rectifier module, synchronous Buck circuit, overvoltage protection circuit, supercapacitor group, capacitor voltage measurement module, charging current and resonant voltage measurement module; the transmitting coil passes The magnetic coupling resonance method transmits power to the receiving coil; the main control module determines the real-time charging power based on the charging current and resonance voltage measured by the charging current and resonance voltage measurement module, and outputs the first of two channels based on the real-time charging power and the preset constant power. The PWM signal is sent to the high-frequency full-bridge inverter circuit to adjust the transmit power. At the same time, two second PWM signals are output to the synchronous Buck circuit according to the voltage value of the supercapacitor group measured by the capacitor voltage measurement module to adjust the charging power to complete constant power wireless charging. The system of this invention can adjust the impedance of the receiving end in real time by accurately matching the reflection resistance of the receiving end and combining it with the synchronous Buck circuit, so that the load end can maintain high efficiency and constant power without changing the output power at the transmitting end and the impedance of the energy storage device at the receiving end changes. Charge.

Description of the drawings

Figure 1 shows the topology of the LCC power compensation scheme in one embodiment;

Figure 2 is a structural diagram of an inverter resonant constant power wireless charging system in one embodiment;

Figure 3 is a schematic diagram of a transmitting power module in an embodiment;

Figure 4 is a schematic diagram of a high-frequency full-bridge inverter circuit in another embodiment;

Figure 5 is a schematic diagram of a synchronous Buck circuit in one embodiment.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present application more clear, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present application and are not used to limit the present application.

The transmitter of this system uses full-bridge phase shifting, and the topology of the LCC power compensation scheme is shown in Figure 1. The full-bridge drive solution enables a wider power supply voltage range, LCC power compensation can reduce power changes caused by load changes, and slow-start protection and power closed-loop control ensure that the transmitter will not be damaged due to overshoot under high-power conditions. It adopts domestic Risc-v architecture monolithic chip, which is cheap and has on-board external PWM input interface and bus current and voltage detection interface, allowing the use of external expansion equipment to monitor power or directly control output. For the receiving end, this system uses synchronous Buck to adjust the impedance of the receiving end in real time. It only needs to receive the vibration of the coil to achieve constant power at the receiving end without affecting the working status of the transmitting end.

In one embodiment, as shown in FIG. 2 , an inverter resonant constant power wireless charging system is provided. The system includes: a transmitting end 10 and a receiving end 20 .

The transmitting end 10 includes: transmitting power module 101, high-frequency full-bridge inverter circuit 102, LCC power compensation module 103, transmitting coil 104, main control module 105 and bus voltage and current measurement module 106; transmitting power module 101 and high-frequency full-bridge inverter circuit 102 The input end is connected, the output end of the high-frequency full-bridge inverter circuit 102 is connected to the LCC power compensation module 103, and the LCC power compensation module 103 is connected to the transmitting coil 104; the bus voltage and current measurement module 106 is used to measure the bus voltage and current and transmitted to the main control module 105.

The receiving end 20 includes: receiving coil 201, symmetrical LCC power compensation circuit 202, rectifier module 203, synchronous Buck circuit 204, overvoltage protection circuit 205, supercapacitor group 206, capacitor voltage measurement module 207, and charging current and resonance voltage measurement module 208 .

The transmitting coil 104 transmits power to the receiving coil 201 through magnetic coupling resonance; the receiving coil 201 is connected to the rectifier module 203 through the symmetrical LCC power compensation circuit 202, and the rectifier module 203 is connected to the input end of the synchronous Buck circuit 204. The synchronous Buck circuit 204 The output end is connected to the supercapacitor group 206 through the overvoltage protection circuit 205; the charging current and resonance voltage measurement module 208 is used to measure the voltage and current values of the signals output by the rectifier module 203, and transmit them to the main control module 105; the capacitance voltage measurement module 207 is used to measure the capacitor voltage of the supercapacitor group 206 and transmit it to the main control module 105 .

The main control module 105 determines the real-time charging power based on the charging current and resonant voltage measured by the charging current and resonant voltage measurement module 208, and outputs two first PWM signals to the high-frequency full-bridge inverter circuit 102 based on the real-time charging power and the preset constant power. Adjust the transmit power and output two second PWM signals to the synchronization Buck circuit 204 at the same time to adjust the charging power to complete constant power wireless charging.

Specifically, the transmitting power module 101 has hard protections such as over-temperature, over-current, and over-voltage, while the main control module can implement soft protections such as over-current, over-voltage, and battery low voltage, with high safety. The transmitting end is in constant power working state, the working state of components is more stable, and the life of the whole board is longer.

The transmitting power module 101 is used to output the transmitting voltage to the frequency full-bridge inverter circuit 102, and is also used to supply power to the receiving end; the schematic diagram of the transmitting power module 101 is shown in Figure 3. In Figure 3, U1 is the SP1N28STER step-down converter. .

The high-frequency full-bridge inverter circuit 102 is used to convert the received DC signal into an AC transmit signal and transmit it to the LCC power compensation module 103.

The LCC power compensation module 103 is used to perform power compensation on the AC transmission signal and provide the resulting transmission power to the transmission coil.

The transmitting coil 104 is used to transmit the transmitting power to the receiving coil 201 through magnetic coupling resonance;

The bus voltage and current measurement module is used to measure the bus voltage and current of the transmitting power module 101, and transmit the measured values to the main control module 105 for connection.

The receiving coil is used to receive the transmit power and transmit it to the rectifier module 203 .

The rectification module 203 is used to rectify the received transmission power and transmit it to the synchronous Buck circuit 204.

The synchronous Buck circuit is used to adjust the power charged to the supercapacitor group to achieve constant power charging of the capacitor.

Overvoltage protection circuit is used to protect the output terminal from overvoltage.

Supercapacitor bank is used to store electric energy for constant power charging.

The above-mentioned inverter resonant constant power wireless charging system includes: a transmitting end and a receiving end; the transmitting end includes: transmitting power module, high-frequency full-bridge inverter circuit, LCC power compensation module, transmitting coil, main control module and bus voltage and current measurement Module; the receiving end includes: receiving coil, symmetrical LCC power compensation circuit, rectifier module, synchronous Buck circuit, over-voltage protection circuit, supercapacitor group, capacitor voltage measurement module, charging current and resonant voltage measurement module; the transmitting coil resonates through magnetic coupling way to transmit power to the receiving coil; the main control module determines the real-time charging power based on the charging current and resonant voltage measured by the charging current and resonant voltage measurement module, and outputs two first PWM signals to The high-frequency full-bridge inverter circuit adjusts the transmit power, and at the same time outputs two second PWM signals to the synchronous Buck circuit according to the voltage value of the supercapacitor group measured by the capacitor voltage measurement module to adjust the charging power to complete constant power wireless charging. The system of this invention can adjust the impedance of the receiving end in real time by accurately matching the reflection resistance of the receiving end and combining it with the synchronous Buck circuit, so that the load end can maintain high efficiency and constant power without changing the output power at the transmitting end and the impedance of the energy storage device at the receiving end changes. Charge.

This system can realize high-power wireless power transmission at low cost. The maximum transmit power of the same type of MOS tube using this solution can reach 1200W. After changing the MOS tube model, it can reach higher power, which is far more than the charging power of service robots currently on the market. Moreover, this solution can realize long-distance power transmission, and the charging equipment is small in size.

In one embodiment, the main control module includes a domestic microcontroller with Risc-v architecture.

As the first choice, the single-chip microcomputer chip using domestic Risc-v architecture has low price and stable supply.

In one embodiment, a high-frequency full-bridge inverter circuit includes: two high-frequency half-bridge gate drivers and a high-frequency full-bridge inverter.

The input terminals of the two high-frequency half-bridge gate drivers are connected to the main control module. The two output terminals of the first high-frequency half-bridge gate driver are respectively connected to the two MOSs of the first half-bridge of the high-frequency full-bridge inverter. The gates of the tubes are connected, and the two output terminals of the second high-frequency half-bridge gate driver are respectively connected to the gates of the two MOS tubes of the second half-bridge of the high-frequency full-bridge inverter. The output terminals of the half bridge and the second half bridge are respectively connected to the two input terminals of the LCC power compensation module.

The high-frequency full-bridge inverter circuit is shown in Figure 4. In Figure 4, Q4, Q5, Q6 and Q7 are all N-channel field effect transistors HYG180N10LS1P, and U5 and U6 are both high-frequency half-bridge gate drivers DGD0506A.

In one embodiment, the synchronous Buck circuit includes: a half-bridge driver module, a MOS half-bridge, and a filter module.

The two input terminals of the half-bridge drive module are connected to the main control module, and the two output terminals of the half-bridge driver module are respectively connected to the gates of the MOS tubes of the upper and lower arms of the MOS half-bridge. The source of the MOS of the bridge arm is connected to the drain of the MOS of the lower arm of the MOS half bridge. The source of the MOS of the lower arm of the MOS half bridge is connected to an input terminal of the filter module. The lower arm of the MOS half bridge The drain of the MOS is connected to the other input terminal of the filter module, and the output terminal of the filter module is connected to the overvoltage protection circuit.

The schematic diagram of the synchronous Buck circuit is shown in Figure 5. In Figure 5, U2 is the half-bridge driver chip EG2104. U2 uses the intelligent diode controller LM74610QDGKTQ1. Q1 and Q3 are both N-channel enhancement MOS tubes IRLR3410TRPBF. Q2 is N-channel enhancement. Type MOS tube TPH1R403NL.

In one embodiment, at the transmitter end, the main control module is also used to determine whether the transmit power module is in a normal state based on the bus current and bus voltage of the transmit power module measured by the bus voltage and current measurement module. If the state is normal, ladder power control is used. method to output the first PWM signal to the high-frequency full-bridge inverter circuit to control the high-frequency full-bridge inverter circuit; the ladder power control method is: linearly regulate 50%-100% target power in 0.0s-1.0s, and linearly regulate after 1.0s 100% target power.

Specifically, the transmitter uses ladder power control mainly because the current sampling signal has a charging effect. Since the current sampling output will be lower than the real power at the beginning, which will cause distortion and overshoot, it is divided into three ladder controls, 0.0s-1.0s linear Adjust 50%-100% target power, and 100% target power after 1.0s. The power control part allows the power to be lower than the target power but strictly limits the power to exceed the target power. Therefore, when the power is lower than the target power and exceeds 10W, the control is normally controlled. When the power is in the range of -5W-10W, the control is weakened. When the power exceeds the target power by 5W, the phase shift is strictly controlled and downregulated. This may It will cause some oscillation but can avoid long-term overshoot caused by hysteresis.

In one embodiment, the main control module is also used to protect the transmitter from overcurrent; the transmitter overcurrent protection refers to: reading the bus voltage and current measured by the bus voltage and current measurement module at a predetermined frequency (preferably, the predetermined frequency is 100Hz). Bus current value, obtain the current sampling value, and store it in the predetermined buffer array (as a preferred option, the predetermined buffer array uses a buffer array with a length of 20 and a data type of floating point), and uses Butterworth for the current sampling value. Filter with a low-pass filter, then count all current data (i.e. 20 current data) in the predetermined buffer array, count the linear correlation coefficient and peak difference of the current data within 1 second, and set the weighting of the linear correlation coefficient and peak difference coefficient, if the weighted sum of the linear correlation coefficient and the peak difference exceeds the preset threshold, the current system may have overcurrent, and the main control module stops outputting the first PWM signal to turn off the MOS tube of the high-frequency full-bridge inverter circuit.

Specifically, the overcurrent detection idea is to read the bus current value at a frequency of 100Hz and store it in a buffer array with a length of 20 and a data type of floating point. Due to the error of the sampling effect, there will be many low-frequency current sampling values. To avoid interference, a Butterworth band-stop filter is designed. The filter order is 2. The upper stop-band cut-off frequency of the digital filter is 15 Hz, the lower stop-band cut-off frequency is 10 Hz, and the sampling frequency is 100 Hz.

Normalized Butterworth low-pass filter form:

;

calculate and/> , in/> Substitute/> ;

;

;

;

;

;

;

;

Count the 20 current data in the buffer array. Within 1 second, count the linear correlation coefficient and peak difference of the current data. Set the linear correlation coefficient and the weighting coefficients α and β of the peak difference. If the linear correlation coefficient and the weighting of the peak difference are If the sum exceeds the set threshold, it can be considered that the current system is diverging and there is a possibility of overcurrent. At this time, the microcontroller stops outputting PWM waves and turns off the MOS tube.

In one embodiment, the main control module is also used to protect the receiving end from receiving overcurrent; receiving overcurrent protection means: when the voltage difference on both sides of the receiving coil is less than the preset voltage difference threshold, the charge and discharge current is set is the preset value (higher value); when the voltage difference on both sides of the receiving coil is greater than the preset voltage difference threshold, the charge and discharge current is limited. The current calculation formula is:

;

in, is the maximum charging current allowed by the current capacitor,/> is the capacitor voltage (real-time measurement),/> is the input voltage (after rectification),/> It is the maximum current allowed by MOS.

Specifically, the current on both sides of the receiving coil at the receiving end satisfies the following conditions: , in order to prevent MOS overcurrent caused by excessive voltage difference on both sides of the receiving coil, a dynamic current threshold algorithm is proposed. When the voltage difference is small, the charge and discharge current can be set at a higher value. When the voltage difference is large, the charge and discharge current should be limited in order to avoid overcurrent of the capacitor MOS. The calculation formula is:/> .

In one embodiment, the main control module is also used to perform hardware self-test on the receiving end circuit and perform running fault detection on the transmitting end and receiving end; where the running fault detection includes: over- and under-voltage anomalies, over-current flow, charging and discharging abnormalities; the process of hardware self-test on the receiving end circuit includes: within the preset time period from the start of transmission (as the preset time period is 0-0.1s), detect the receiving end voltage and current, and store them in predetermined Buffer array (as a preferred option, the predetermined buffer data type is a buffer array with a Float length of 20), and the white noise is filtered out through low-pass filtering, and the duty cycle of the upper and lower MOS tubes is linearly changed. According to the voltage and current data, Calculate the voltage change rate, duty cycle change rate and current change rate. If the voltage change rate is less than the duty cycle change rate, it is determined that the MOS tube is damaged. If the ratio of the voltage change rate to the duty cycle change rate is greater than the upper threshold (threshold The upper limit is preferably 1.0±0.1), and the current change rate is less than the lower limit of the current change rate threshold (the lower limit of the current change rate threshold is preferably: the set maximum power , it is concluded that the inductor has been damaged; the method for determining the charge and discharge abnormality is: if the difference between the DC-DC set power and the actual calculated power is greater than the preset value for a long time, a charge and discharge abnormality will occur.

Specifically, the idea of runtime fault detection is common to the transmitter and receiver. Runtime fault detection detects faults promptly and shuts down the output to avoid further damage. Fault detection during operation is divided into over- and under-voltage abnormalities, over-current, and charging and discharging abnormalities. What needs to be highlighted is charge and discharge anomalies, which can detect charge and discharge power abnormalities caused by MOS damage and prevent short circuits caused by MOS breakdown. The specific judgment method is that if the DC-DC set power and the actual calculated power differ for a long time If it is too large, it is considered that charging and discharging abnormalities have occurred.

In one of the embodiments, the main control module is also used to adjust the output voltage of the synchronous Buck circuit based on the capacitance voltage of the supercapacitor group measured by the collected capacitance voltage measurement module, so that the supercapacitors in the supercapacitor group can operate without breakdown. Constant power charging.

Specifically, because the capacitor impedance changes due to the capacitor voltage, the capacitor energy , the main control module detects the capacitor voltage in real time through the ADC sampling interface, and adjusts the output voltage of the synchronous Buck circuit to ensure that the capacitor is charged at constant power without breakdown.

In one embodiment, an inverter resonant constant power wireless charging system is provided. The main power control circuit at the transmitter end of the system adopts a high-frequency full-bridge inverter circuit, supports a wide range of voltage inputs, and has slow start, Over-current protection, over-voltage protection, low-voltage protection, over-temperature protection and many other safety functions. The overall working efficiency is high and the temperature rise is low. It has been measured that a 400W capacitor bank was continuously charged with 1440 Joules of energy four times, and the temperature rise was <10°C. After adding external active heat dissipation, a 600W capacitor bank that was continuously charged with 1440 Joules of energy and the temperature was measured four times. Rise <10℃. The measured acceptance efficiency of the receiving end can be stabilized at around 80%. With active heat dissipation added, the overall temperature rise is <10°C after four consecutive charges. This solution has the advantages of high reliability, simple circuit topology, and low cost.

In one embodiment, an inverter resonance constant power wireless charging control method is provided, which method is applied to any of the above inverter resonance constant power wireless charging systems to achieve constant power wireless charging; the method includes the following steps:

Step 100: The main control module receives the bus voltage and bus current value of the transmitting power supply measured by the bus voltage and current measurement module, and determines whether the transmitting power supply can normally provide electric energy based on the bus voltage and the bus current value.

Step 102: When the transmitting power supply can provide power normally:

The main control module determines the real-time charging power based on the received charging current and the resonant voltage measured by the resonant voltage measurement module, and outputs two first PWM signals to the high-frequency full bridge based on the real-time charging power and the preset constant power. The inverter circuit adjusts the transmit power;

Step 104: When the main control module receives the capacitor voltage value of the supercapacitor group measured by the capacitor voltage measurement module, it outputs two second PWM signals to the synchronous Buck circuit for charging power adjustment to complete constant power wireless charging.

The technical features of the above embodiments can be combined in any way. To simplify the description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, all possible combinations should be used. It is considered to be within the scope of this manual.

The above-described embodiments only express several implementation modes of the present application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that, for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all fall within the protection scope of the present application. Therefore, the scope of protection of this application should be determined by the appended claims.

Claims (10)

1. An inverted resonant constant power wireless charging system, the system comprising: a transmitting end and a receiving end;

the transmitting end comprises: the device comprises a transmitting power supply module, a high-frequency full-bridge inverter circuit, an LCC power compensation module, a transmitting coil, a main control module and a bus voltage and current measurement module; the power supply module is connected with the input end of the high-frequency full-bridge inverter circuit, the output end of the high-frequency full-bridge inverter circuit is connected with the LCC power compensation module, and the LCC power compensation module is connected with the transmitting coil; the bus voltage and current measurement module is used for measuring bus voltage and current of the emission power supply module and transmitting the bus voltage and current to the main control module;

the receiving end comprises: the device comprises a receiving coil, a symmetrical LCC power compensation circuit, a rectification module, a synchronous Buck circuit, an overvoltage protection circuit, a super capacitor group, a capacitor voltage measurement module and a charging current and resonance voltage measurement module;

the transmitting coil transmits power to the receiving coil in a magnetic coupling resonance mode; the receiving coil is connected with the rectifying module through the symmetrical LCC power compensation circuit, the rectifying module is connected with the input end of the synchronous Buck circuit, and the output end of the synchronous Buck circuit is connected with the super capacitor group through the overvoltage protection circuit; the charging current and resonance voltage measuring module is used for measuring the voltage and current values of signals output by the rectifying module and transmitting the voltage and current values to the main control module; the capacitor voltage measurement module is used for measuring the capacitor voltage of the super capacitor group and transmitting the capacitor voltage to the main control module;

the main control module determines real-time charging power according to the charging current and resonance voltage measured by the charging current and resonance voltage measuring module, outputs two paths of first PWM signals to the high-frequency full-bridge inverter circuit to adjust transmitting power according to the real-time charging power and preset constant power, and simultaneously outputs two paths of second PWM signals to the synchronous Buck circuit to adjust the charging power according to the voltage value of the super capacitor group measured by the capacitor voltage measuring module, so that constant-power wireless charging is completed.

2. The system of claim 1, wherein the master control module comprises a domestic single-chip microcomputer of Risc-v architecture.

3. The system of claim 1, wherein the high frequency full-bridge inverter circuit comprises: two high frequency half-bridge gate drivers and a high frequency full-bridge inverter;

the input ends of the two high-frequency half-bridge grid drivers are connected with the main control module, the two output ends of the first high-frequency half-bridge grid driver are respectively connected with the grids of the two MOS tubes of the first half-bridge of the high-frequency full-bridge inverter, the two output ends of the second high-frequency half-bridge grid driver are respectively connected with the grids of the two MOS tubes of the second half-bridge of the high-frequency full-bridge inverter, and the output ends of the first half-bridge and the second half-bridge of the high-frequency full-bridge inverter are respectively connected with the two input ends of the LCC power compensation module.

4. The system of claim 1, wherein the synchronous Buck circuit includes: the MOS half-bridge filter comprises a half-bridge driving module, an MOS half-bridge and a filtering module;

the two input ends of the half-bridge driving module are connected with the main control module, the two output ends of the half-bridge driving module are respectively connected with the grid electrodes of the MOS tubes of the upper bridge arm and the lower bridge arm of the MOS half-bridge, the source electrode of the MOS of the upper bridge arm of the MOS half-bridge is connected with the drain electrode of the MOS of the lower bridge arm of the MOS half-bridge, the source electrode of the MOS of the lower bridge arm of the MOS half-bridge is connected with one input end of the filtering module, the drain electrode of the MOS of the lower bridge arm of the MOS half-bridge is connected with the other input end of the filtering module, and the output end of the filtering module is connected with the overvoltage protection circuit.

5. The system of claim 1, wherein at the transmitting end, the main control module is further configured to determine whether the transmitting power module is in a normal state according to the bus current and the bus voltage of the transmitting power module measured by the bus voltage and current measurement module, and if the transmitting power module is in a normal state, output a first PWM signal to the high-frequency full-bridge inverter circuit by adopting a step power control manner, so as to control the high-frequency full-bridge inverter circuit;

wherein, the ladder power control mode is: and linearly regulating and controlling 50% -100% of target power at 0.0s-1.0s, and linearly regulating and controlling 100% of target power at 1.0 s.

6. The system of claim 1, wherein the master control module is further configured to perform transmit over-current protection on a transmitting end; the emission overcurrent protection means that: and reading the bus current value measured by the bus voltage and current measurement module according to a preset frequency to obtain a current sampling value, storing the current sampling value in a preset buffer area array, filtering the current sampling value by adopting a Butterworth low-pass filter, counting all current data in the preset buffer area array, counting linear correlation coefficients and peak differences of the current data within 1 second, setting weighting coefficients of the linear correlation coefficients and the peak differences, and if the weighted sum of the linear correlation coefficients and the peak differences exceeds a preset threshold value, enabling the current system to have overcurrent, wherein the main control module stops outputting a first PWM signal to turn off a MOS tube of the high-frequency full-bridge inverter circuit.

7. The system of claim 1, wherein the master control module is further configured to receive over-current protection for the receiving end; the receiving overcurrent protection means that: when the voltage difference between two sides of the receiving coil is smaller than a preset voltage difference threshold value, the charge and discharge current is set to be a preset value; when the voltage difference between two sides of the receiving coil is larger than a preset voltage difference threshold value, limiting charge and discharge currents, wherein a current calculation formula is as follows:

；

wherein,for the maximum charge current allowed by the present capacitor, < >>For the capacitance voltage measured in real time, < >>For the rectified input voltage, +.>Maximum current allowed to pass for MOS.

8. The system of claim 1, wherein the master control module is further configured to perform hardware self-test on the receiver circuit and perform fault detection on the transmitter and the receiver during operation; wherein the runtime fault detection comprises: abnormal overvoltage and undervoltage, overcurrent and abnormal charge and discharge;

the process of performing hardware self-checking on the receiving end circuit comprises the following steps: detecting voltage and current of a receiving end in a preset time period from the beginning of emission, respectively storing the voltage and the current in a preset buffer array, filtering white noise through low-pass filtering, linearly changing the duty ratio of an upper MOS tube and a lower MOS tube, calculating the voltage change rate, the duty ratio change rate and the current change rate according to voltage and current data, judging that the MOS tube is damaged if the voltage change rate is smaller than the duty ratio change rate, and judging that the inductor is damaged if the ratio of the voltage change rate to the duty ratio change rate is larger than the upper threshold limit and the current change rate is smaller than the lower threshold limit;

the method for judging the charge-discharge abnormality comprises the following steps: if the difference between the DC-DC set power and the actual calculated power is larger than a preset value for a long time, the charge and discharge abnormality occurs.

9. The system of claim 1, wherein the master control module is further configured to adjust an output voltage of the synchronous Buck circuit according to the collected capacitor voltage of the supercapacitor group measured by the capacitor voltage measurement module, so that the supercapacitor in the supercapacitor group is charged with constant power without breakdown.

10. An inversion resonance constant power wireless charging control method, which is characterized in that the method is applied to the inversion resonance constant power wireless charging system according to any one of claims 1-9 to realize constant power wireless charging; the method comprises the following steps:

the main control module receives the bus voltage and the bus current value of the emission power supply measured by the bus voltage and current measuring module, and determines whether the emission power supply can normally supply electric energy or not according to the bus voltage and the bus current value;

under the condition that the transmitting power supply can normally supply electric energy:

the main control module determines real-time charging power according to the received charging current and the charging current and resonant voltage measured by the resonant voltage measuring module, and outputs two paths of first PWM signals to the high-frequency full-bridge inverter circuit to adjust transmitting power according to the real-time charging power and preset constant power;

when the capacitance voltage value of the super capacitor group measured by the capacitance voltage measuring module received by the main control module, two paths of second PWM signals are output to the synchronous Buck circuit to adjust charging power, and constant-power wireless charging is completed.