Wireless electric energy transmission control method with controllable output

Abstract

The invention discloses a wireless power transmission control method with controllable output, and the control method is realized through a control circuit which comprises a primary full-bridge circuit, an LCC-S compensation network, a secondary uncontrolled rectification circuit, a sampling circuit and a control circuit. The method comprises the following steps: constructing an equivalent simplified circuit for the control circuit, and setting initial parameters; analyzing the equivalent simplified circuit based on a fundamental wave approximation method, and constructing a voltage and current equivalent equation according to the initial parameters; introducing a detuning coefficient, performing detuning analysis on the equivalent simplified circuit according to a voltage and current equivalent equation, and calculating the detuning coefficient to obtain a detuning coefficient calculation value; calculating an equivalent input impedance angle of the primary side circuit according to the detuning coefficient calculation value; and driving ZVS wireless power transmission control according to the equivalent input impedance angle based on the detuning value constraint and the impedance value constraint. The technical problems that in the prior art, a circuit structure and a ZVS control method are complex, the actual scene control requirement cannot be met, and the system maintenance difficulty is increased can be solved.

Description

Technical Field

[0001] The present application relates to the field of wireless charging technology, and in particular to a wireless power transmission control method with controllable output. Background Art

[0002] With the continuous advancement of wireless charging technology, new energy electric vehicles are also constantly updating and iterating, and the demand for wireless charging is increasing. Especially in the selection of charging efficiency and charging mode, with the changes in different application scenarios, the use of different resonant compensation topologies can achieve unique output characteristics, thereby achieving constant current or constant voltage control. However, despite the great potential of wireless charging technology, there are still many problems in practical applications. At the same time, under certain specific topologies, only specific charging modes can be supported, which limits the flexibility and optimization space of the system. At the same time, in the field of wireless power transmission, it is necessary to invert the DC source to obtain the AC source, but ZVS, that is, zero voltage switching, cannot be achieved under non-detuned conditions of the system; this also leads to excessive spikes in the system resonant current, thereby breaking down the components on the circuit board.

[0003] The circuit topology structure based on the existing wireless power transmission control method is too complex, and too many components will increase the overall cost of the system; moreover, the existing zero-voltage start-up control method is also relatively complex, which cannot meet the control requirements of actual scenarios and will also increase the difficulty of system maintenance. Summary of the invention

[0004] The present application provides a wireless power transmission control method with controllable output, which is used to solve the technical problems that the circuit topology structure and zero-voltage start-up control method in the prior art are relatively complex, cannot meet the actual scene control requirements, and also increase the difficulty of system maintenance.

[0005] In view of this, the present application provides a controllable output wireless power transmission control method, the control method is implemented by a control circuit, the control circuit includes: a primary side full bridge circuit, an LCC-S compensation network, a secondary side uncontrolled rectifier circuit, a sampling circuit and a control circuit;

[0006] The primary full-bridge circuit includes four MOSFET switch tubes, and two of the MOSFET switch tubes constitute a primary bridge arm, and ZVS zero voltage switching is achieved based on phase shift control;

[0007] The LCC-S compensation network includes a primary coil, a primary compensation inductor and a primary compensation capacitor, wherein the primary compensation inductor and two primary compensation capacitors are connected in parallel to form a T-type structure;

[0008] The secondary side uncontrolled rectifier circuit includes a secondary side full bridge circuit and a secondary side compensation network;

[0009] The sampling circuit is used to collect the current of the primary full-bridge circuit and the voltage of the secondary full-bridge circuit;

[0010] The control circuit includes a PWM drive circuit, a PID control circuit and a DSP control circuit, which are used to control wireless power transmission;

[0011] The control method comprises:

[0012] Constructing an equivalent simplified circuit for the control circuit and setting initial parameters;

[0013] Analyzing the equivalent simplified circuit based on the fundamental wave approximation method, and constructing a voltage and current equivalent equation according to the initial parameters;

[0014] Introducing a detuning coefficient, performing a detuning analysis on the equivalent simplified circuit according to the voltage-current equivalent equation, and calculating the detuning coefficient to obtain a calculated value of the detuning coefficient;

[0015] Calculating the equivalent input impedance angle of the primary circuit according to the calculated value of the detuning coefficient;

[0016] Based on the detuning value constraint and the impedance value constraint, the ZVS zero voltage switching control is driven according to the equivalent input impedance angle to realize wireless power transmission control.

[0017] Preferably, the first MOSFET switch tube and the second MOSFET switch tube in the primary full-bridge circuit constitute a primary super-forward arm;

[0018] The third MOSFET switch tube and the fourth MOSFET switch tube constitute a primary side lagging arm;

[0019] The ZVS zero voltage switching of the MOSFET switch tubes of the primary leading arm and the primary lagging arm is controlled by a preset phase shift angle.

[0020] Preferably, one end of the primary coil in the LCC-S compensation network is connected in series with a primary compensation capacitor and a primary compensation inductor and then connected to the positive end of the midpoint of the primary bridge arm in the primary full-bridge circuit;

[0021] The other end of the primary coil in the LCC-S compensation network is connected to the negative end of the midpoint of the primary bridge arm in the primary full-bridge circuit.

[0022] Preferably, the secondary full-bridge circuit comprises four symmetrical diodes, and the output ends are respectively connected in parallel with the filter capacitor and the load;

[0023] The secondary compensation network includes a receiving coil and a secondary compensation capacitor, and the secondary compensation network is connected to the midpoint of the secondary bridge arm in the secondary full-bridge circuit.

[0024] Preferably, the DSP control circuit generates a PID control instruction according to the current and the voltage collected by the sampling circuit;

[0025] The PID control circuit generates a conduction angle according to the PID control instruction, and triggers the PWM drive circuit to drive the operation of the primary full-bridge circuit through the conduction angle.

[0026] Preferably, the introducing of the detuning coefficient, performing a detuning analysis on the equivalent simplified circuit according to the voltage-current equivalent equation, and calculating the detuning coefficient to obtain a calculated value of the detuning coefficient, comprises:

[0027] Introducing a detuning coefficient to perform resonance adjustment on the voltage-current equivalent equation to obtain a resonance equivalent relationship equation;

[0028] A detuning analysis is performed on the equivalent simplified circuit according to the resonance equivalent relationship equation, and the detuning coefficient is calculated to obtain a detuning coefficient calculation value.

[0029] Preferably, the introducing of the detuning coefficient, performing a detuning analysis on the equivalent simplified circuit according to the voltage-current equivalent equation, and calculating the detuning coefficient to obtain a calculated value of the detuning coefficient, further comprises:

[0030] Constructing an output power expression of the system according to the detuning coefficient;

[0031] The detuning coefficient is differentiated according to the output power expression, the detuning coefficient is calculated when the partial derivative value is 0, and a detuning coefficient reference value is obtained.

[0032] Preferably, the calculating the equivalent input impedance angle of the primary circuit according to the calculated value of the detuning coefficient includes:

[0033] Calculating the equivalent input impedance of the primary circuit according to the calculated value of the detuning coefficient and the secondary primary reflected impedance value;

[0034] An equivalent input impedance angle of the primary circuit is determined according to the equivalent input impedance.

[0035] Preferably, the method of driving ZVS zero voltage switching control based on the detuning value constraint and the impedance value constraint according to the equivalent input impedance angle to realize wireless power transmission control further includes:

[0036] When the load resistance value changes, a constant current coefficient is introduced to calculate the output current value of the first load, and the output voltage value of the first load is collected, wherein the constant current coefficient is calculated according to the constant current condition;

[0037] Calculating a constant current phase shift angle of the primary full-bridge circuit according to the first load output current value and the first load output voltage value;

[0038] The PID control circuit realizes constant current control of the primary full-bridge circuit according to the constant current phase shift angle.

[0039] Preferably, the method of driving ZVS zero voltage switching control based on the detuning value constraint and the impedance value constraint according to the equivalent input impedance angle to realize wireless power transmission control further includes:

[0040] When the load resistance value changes, a constant voltage coefficient is introduced to calculate the second load output current value, and the second load output voltage value is collected, wherein the constant voltage coefficient is calculated according to the constant voltage condition;

[0041] Calculating a constant voltage phase shift angle of the primary full-bridge circuit according to the second load output current value and the second load output voltage value;

[0042] The PID control circuit realizes constant voltage control on the primary full-bridge circuit according to the constant voltage phase shift angle.

[0043] It can be seen from the above technical solutions that the embodiments of the present application have the following advantages:

[0044] In the present application, a control method for wireless power transmission with controllable output is provided, and the control method is implemented by a control circuit, and the control circuit includes: a primary full-bridge circuit, an LCC-S compensation network, a secondary uncontrolled rectifier circuit, a sampling circuit and a control circuit; the primary full-bridge circuit includes four MOSFET switch tubes, and two MOSFET switch tubes constitute a primary bridge arm, and ZVS zero voltage switching is realized based on phase shift control; the LCC-S compensation network includes a primary coil, a primary compensation inductor and a primary compensation capacitor, and the primary compensation inductor and the two primary compensation capacitors are connected in parallel to form a T-type structure; the secondary uncontrolled rectifier circuit includes a secondary full-bridge circuit and a secondary compensation network; the sampling circuit is used to collect the current of the primary full-bridge circuit and the voltage of the secondary full-bridge circuit; the control circuit includes a PWM drive circuit, a PID control circuit and a DSP control circuit, which are used to control wireless power transmission.

[0045] The control method includes: constructing an equivalent simplified circuit for the control circuit and setting initial parameters; analyzing the equivalent simplified circuit based on the fundamental wave approximation method, and constructing a voltage and current equivalent equation according to the initial parameters; introducing a detuning coefficient, performing a detuning analysis on the equivalent simplified circuit according to the voltage and current equivalent equation, and calculating the detuning coefficient to obtain a calculated value of the detuning coefficient; calculating the equivalent input impedance angle of the primary circuit according to the calculated value of the detuning coefficient; based on the detuning value constraint and the impedance value constraint, driving the ZVS zero voltage switching control according to the equivalent input impedance angle to realize wireless power transmission control.

[0046] The wireless power transmission control method with controllable output provided by the present application realizes the wireless power transmission control of zero voltage switching on of MOSFET switch tube by combining the designed control circuit with the control method, and the phase shift control under the detuning condition is considered in this process; the equivalent input impedance angle used to drive the ZVS zero voltage switching on control is determined based on the equivalent simplified circuit and parameter calculation, and the wireless power transmission control process is limited by the detuning value constraint and the impedance value constraint, which can ensure that this process is more in line with the actual situation and the control effect is more accurate and reliable; and the circuits and operations involved in the process are simple and easy to execute, which can meet the control requirements of actual application scenarios. Therefore, the present application can solve the technical problems that the circuit topology structure and zero voltage switching on control method of the prior art are relatively complex, cannot meet the control requirements of actual scenarios, and increase the difficulty of system maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A schematic diagram of a control circuit structure of a wireless power transmission control method with controllable output provided in an embodiment of the present application;

[0048] Figure 2 A schematic flow chart of a controllable output wireless power transmission control method provided in an embodiment of the present application;

[0049] Figure 3 A schematic diagram of a control circuit of a primary full-bridge circuit with phase shift control provided in an embodiment of the present application;

[0050] Figure 4 An equivalent simplified circuit schematic diagram corresponding to the control circuit provided in the embodiment of the present application;

[0051] Figure 5 A schematic diagram of an equivalent topology of a primary circuit under a detuned condition provided in an embodiment of the present application;

[0052] Figure 6 A schematic diagram of the relationship between the system output voltage and output current after phase shift control under the detuned condition provided in an embodiment of the present application;

[0053] Figure 7 A schematic diagram of a switching signal of a phase-shift control and a waveform of a system output voltage after phase-shift control provided in an embodiment of the present application;

[0054] Figure 8 A schematic diagram showing the relationship between the phase shift conduction angle and the load resistance value under constant current and constant voltage conditions provided in an embodiment of the present application;

[0055] Fig. 9 A schematic diagram of the relationship between load output current and output voltage and load resistance value in different modes provided in an embodiment of the present application. DETAILED DESCRIPTION

[0056] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0057] For easier understanding, see Figure 1 , the present application provides an embodiment of a controllable output wireless power transmission control method, the control method is implemented by a control circuit, and the control circuit includes: a primary side full-bridge circuit, an LCC-S compensation network, a secondary side uncontrolled rectifier circuit, a sampling circuit and a control circuit.

[0058] The primary full-bridge circuit includes four MOSFET switches, and two MOSFET switches form a primary bridge arm, which realizes ZVS zero voltage switching based on phase shift control.

[0059] The LCC-S compensation network includes a primary coil, a primary compensation inductor and a primary compensation capacitor. The primary compensation inductor and two primary compensation capacitors are connected in parallel to form a T-type structure.

[0060] The secondary side uncontrolled rectifier circuit includes a secondary side full bridge circuit and a secondary side compensation network;

[0061] The sampling circuit is used to collect the current of the primary full-bridge circuit and the voltage of the secondary full-bridge circuit;

[0062] The control circuit includes a PWM drive circuit, a PID control circuit and a DSP control circuit, which are used to control wireless power transmission.

[0063] Furthermore, the first MOSFET switch tube and the second MOSFET switch tube in the primary full-bridge circuit constitute a primary super forearm;

[0064] The third MOSFET switch tube and the fourth MOSFET switch tube constitute a primary side lagging arm;

[0065] The ZVS zero voltage turn-on of the MOSFET switch tubes of the primary leading arm and the primary lagging arm is controlled by preset phase shift angle.

[0066] Furthermore, one end of the primary coil in the LCC-S compensation network is connected in series with a primary compensation capacitor and a primary compensation inductor and then connected to the positive end of the middle point of the primary bridge arm in the primary full-bridge circuit;

[0067] The other end of the primary coil in the LCC-S compensation network is connected to the negative end of the midpoint of the primary bridge arm in the primary full-bridge circuit.

[0068] Further, the secondary full-bridge circuit includes four symmetrical diodes, and the output ends are connected in parallel with the filter capacitor and the load respectively;

[0069] The secondary side compensation network includes a receiving coil and a secondary side compensation capacitor, and the secondary side compensation network is connected to the middle point of the secondary side bridge arm in the secondary side full bridge circuit.

[0070] Further, the DSP control circuit generates a PID control instruction according to the current and voltage collected by the sampling circuit;

[0071] The PID control circuit generates a conduction angle according to the PID control instruction, and triggers the PWM drive circuit to drive the operation of the primary full-bridge circuit through the conduction angle.

[0072] It should be noted that the control method of this embodiment needs to be coordinated with a specific control circuit. The control circuit includes not only a primary full-bridge circuit, an LCC-S compensation network, a secondary uncontrolled rectifier circuit, a sampling circuit and a control circuit; it also includes some specific coils, such as a transmitting coil and a receiving coil; and also includes a connected load.

[0073] Figure 1 The primary full-bridge circuit in the embodiment includes four MOSFET switches; the first MOSFET switch and the second MOSFET switch The first primary bridge arm is also the primary super fore arm; the third MOSFET switch tube and the fourth MOSFET switch The second primary bridge arm is also the primary lagging arm. By introducing the phase shift angle, the time when the MOSFET switch tubes of the leading arm and the lagging arm are turned on successively can be controlled, thereby achieving phase shift control of the four MOSFET switch tubes.

[0074] The LCC-S compensation network is the primary compensation network. This topology can support ZVS zero voltage switching control under detuned conditions while ensuring constant current or constant voltage output of the system. The network specifically includes the primary coil , primary compensation inductor And the primary compensation capacitor and , primary compensation inductance With 2 primary compensation capacitors , In parallel, they form a T-shaped structure. In addition, the primary coil One end of the primary compensation capacitor is connected in series with and primary compensation inductance After that, it is connected to the positive end of the midpoint of the primary bridge arm in the primary full-bridge circuit; and the primary coil The other end is connected to the negative end of the midpoint of the primary bridge arm.

[0075] The secondary side uncontrolled rectifier current also includes a full-bridge circuit and a compensation network, namely, a secondary side full-bridge circuit and a secondary side compensation network. Specifically, the secondary side full-bridge circuit is composed of 4 symmetrical diodes, and the output end is connected in parallel with the filter capacitor. and load The receiving coil of the secondary compensation network One end of the secondary compensation capacitor is connected in series Then it is connected to the positive end of the midpoint of the secondary bridge arm, and the other end is connected to the negative end of the midpoint of the secondary bridge arm.

[0076] Figure 1 The control part includes a sampling circuit and a control circuit. The sampling circuit includes a current sampling circuit and a voltage sampling circuit. The current sampling circuit is mainly used to collect the current at the positive end of the midpoint of the primary bridge arm, while the voltage sampling circuit is used to collect the actual voltage at both ends of the load. The control circuit includes a PWM drive circuit, a PID control circuit and a DSP control circuit. The combination of several control circuits can realize ZVS wireless power transmission control. Specifically, the DSP control circuit generates a PID control instruction based on the current and voltage collected by the sampling circuit; the PID control circuit generates a conduction angle based on the PID control instruction, and triggers the PWM drive circuit to drive the operation of the primary full-bridge circuit through the conduction angle. In addition, the phase shift control circuit of the primary full-bridge circuit can be referred to. Figure 3 .

[0077] See also Figure 2 , control methods include:

[0078] Step 101: construct an equivalent simplified circuit for the control circuit and set initial parameters.

[0079] This embodiment is an equivalent simplified circuit constructed for the control circuit. Figure 4 Since the parasitic resistance of the circuit is small, in order to simplify the theoretical analysis, the parasitic resistance in the circuit is ignored in this embodiment. The necessary initial parameters of the circuit can be set according to the circuit construction requirements, and the specific parameters are not limited here.

[0080] Step 102: Analyze the equivalent simplified circuit based on the fundamental wave approximation method, and construct the voltage and current equivalent equation according to the initial parameters.

[0081] analyze Figure 4 The equivalent simplified circuit can be analyzed based on the fundamental wave approximation method, and then the voltage and current equivalent equations can be constructed according to the initial parameters:

[0082]

[0083] in,

[0084]

[0085] in, is the resonant inductor of the primary side, which is connected in series to the transmitter. The parallel resonant capacitor of the transmitter is , and the series compensation capacitor is In addition, the self-inductance of the transmitting coil is , the self-inductance of the receiving coil is , the compensation capacitor at the receiving end is , which is connected in series at the receiving end. is the overall operating angular frequency of the system, is the switching frequency of the MOSFET switch in the system, is the mutual inductance between the transmitting coil and the receiving coil. is the AC equivalent load resistance of the secondary circuit system before rectification, The load value carried by the circuit output. Resonant inductor Impedance; is the resonant capacitor Impedance; is the inductance of the transmitting coil and resonant capacitor The total impedance of the series connection; is the self-inductance of the receiving coil and resonant compensation capacitor The total impedance of the series connection; The DC power supply voltage input to the circuit; is the output voltage after the primary full-bridge circuit is inverted; please refer to Figure 5 , , , The first loop flows through the resonant inductor The current of the second loop flows through the transmitting coil The current of the third loop flows through the equivalent load resistance of current.

[0086] Step 103: introducing a detuning coefficient, performing a detuning analysis on the equivalent simplified circuit according to the voltage-current equivalent equation, and calculating the detuning coefficient to obtain a calculated value of the detuning coefficient.

[0087] Furthermore, step 103 includes:

[0088] The detuning coefficient is introduced to adjust the voltage-current equivalent equation to obtain the resonance equivalent relationship equation;

[0089] According to the resonance equivalent relationship equation, the detuning analysis is performed on the equivalent simplified circuit, the detuning coefficient is calculated, and the calculated value of the detuning coefficient is obtained.

[0090] It should be noted that, since the existing MOSFET switch tube cannot achieve ZVS control, it will cause excessive MOSFET switching losses, thereby reducing the transmission efficiency of the system. Therefore, phase shift control under system detuning conditions is introduced to achieve zero voltage turn-on of the MOSFET switch tube through design parameters.

[0091] Figure 5 In this embodiment, the detuning coefficient is introduced to analyze the detuning of the system, so that Figure 5 The resonant inductor in the first loop With resonant capacitor There is no quasi-resonance between the two, so the voltage-current equivalent equation , , It can be converted to:

[0092]

[0093] Then the resonant capacitor in the second loop , and the transmitting coil self-inductance Quasi-resonance occurs between the three, which means that the primary circuit is inductive as a whole.

[0094] See also Figure 6 In full-bridge phase-shift control, the voltage output by the primary circuit of the phase-shift control is required to be ahead of its output current as a whole, so as to achieve the ZVS zero voltage turn-on of the four symmetrical MOSFET switches of the primary voltage. In the ZVS control mode, the voltage of the MOSFET switch tube will first drop to 0 and then turn on; therefore, the turn-on of the MOSFET switch tube occurs at zero voltage, thus avoiding the switching loss caused by the simultaneous existence of voltage and current; reducing the spike effect caused by the sudden change of voltage and current during the switching process, reducing the switching loss and improving the system efficiency.

[0095] Combining the above formulas, we can get some current parameters of the system:

[0096]

[0097] According to the above analysis, it can be found that the output voltage and current of the system circuit are both related to the equivalent load resistance. That is, when ZVS control is implemented, if the load resistance of the system changes, the system cannot achieve constant current or constant voltage output.

[0098] Combination , , The expression and Figure 5 Detuning analysis can be performed to calculate the detuning coefficient: The resonant capacitance can also be determined simultaneously. , and , so the overall expression of the relevant parameters that can be determined by this analysis is:

[0099]

[0100] According to the detuning coefficient expression, we can first assume that the detuning coefficient , first set the resonant inductance according to the formula The parameters estimate the resonant capacitance at this time On this basis, gradually increase the resonant capacitor , select the appropriate ,satisfy . So that the detuning coefficient at this time . That is, the detuning coefficient can be based on the resonant capacitor By adjusting the size parameters, the detuning coefficient is dynamically updated according to the control requirements of the context, thereby achieving a more reliable ZVS zero voltage switch-on.

[0101] Furthermore, step 103 further includes:

[0102] Construct the output power expression of the system based on the detuning coefficient;

[0103] The detuning coefficient is derived according to the output power expression, the detuning coefficient is calculated when the partial derivative value is 0, and the reference value of the detuning coefficient is obtained.

[0104] Due to the resonant inductance of the primary side It is a parameter that can be considered as a setting, so the calculated value of the detuning coefficient may still have a certain error, and its accuracy and reliability cannot be guaranteed. Therefore, this embodiment calculates a detuning coefficient reference value by optimizing the system power, and regulates the detuning coefficient based on the detuning coefficient reference.

[0105] In order to make the system output higher output power at all times and improve the transmission efficiency of the system, the system output power expression under constant current or constant voltage can be constructed, that is, the output power expression:

[0106]

[0107] In order to clarify the detuning coefficient and system output power The relationship between right By finding the first-order partial derivative and setting it to 0, we can get the reference value of the detuning coefficient :

[0108]

[0109] Since the The second-order partial derivative of is less than 0, that is, The selected value can make the system output power reach the maximum value, so the detuning coefficient calculated value As close as possible to the detuning coefficient reference value So in this embodiment, a constraint can be set on the detuning value: .

[0110] Step 104: Calculate the equivalent input impedance angle of the primary circuit according to the calculated value of the detuning coefficient.

[0111] Furthermore, step 104 includes:

[0112] Calculate the equivalent input impedance of the primary circuit based on the calculated value of the detuning coefficient and the secondary primary reflection impedance value;

[0113] Determine the equivalent input impedance angle of the primary circuit based on the equivalent input impedance.

[0114] according to Figure 5 and the calculated detuning coefficient and secondary source reflection impedance The equivalent input impedance of the primary voltage can be calculated:

[0115]

[0116] Among them, the secondary source reflection impedance value It refers to the impedance value reflected from the secondary receiving coil to the primary transmitting coil, which can be expressed as:

[0117]

[0118] Combining the above three current parameter expressions, we can get:

[0119]

[0120] According to the equivalent input impedance The expression can determine the equivalent input impedance angle of the primary circuit :

[0121]

[0122] The value range of the equivalent input impedance angle is , the calculated equivalent input impedance angle Whether it can be used directly for system control still needs to be determined If it is true, it can be used for subsequent control. Otherwise, reselect parameters and adjust the detuning coefficient.

[0123] Step 105: Based on the detuning value constraint and the impedance value constraint, ZVS zero voltage switching control is driven according to the equivalent input impedance angle to achieve wireless power transmission control.

[0124] In addition to the detuning constraints, , and also requires the calculated value of the detuning coefficient Must be greater than 1, that is ; while the impedance value constraint refers to , is the phase shift angle, which can be set according to actual conditions; the mutual inductance value satisfies:

[0125]

[0126] Specifically, it can be based on the mutual inductance between the transmitting coil and the receiving coil Select a value from the range of .

[0127] When the detuning coefficient is calculated, and the equivalent input impedance angle Only when the above constraints are met can the primary circuit be inductive, the input voltage leads the input current, and then the ZVS zero voltage switching based on phase shift control is achieved by controlling according to the equivalent input impedance angle.

[0128] Furthermore, step 105 further includes:

[0129] When the load resistance value changes, a constant current coefficient is introduced to calculate the output current value of the first load, and the output voltage value of the first load is collected. The constant current coefficient is calculated according to the constant current condition;

[0130] Calculate the constant current phase shift angle of the primary full-bridge circuit according to the first load output current value and the first load output voltage value;

[0131] The constant current control of the primary full-bridge circuit is achieved through the PID control circuit according to the constant current phase shift angle.

[0132] Furthermore, step 105 further includes:

[0133] When the load resistance value changes, a constant voltage coefficient is introduced to calculate the second load output current value, and the second load output voltage value is collected. The constant voltage coefficient is calculated according to the constant voltage condition.

[0134] Calculating the constant voltage phase shift angle of the primary full-bridge circuit according to the second load output current value and the second load output voltage value;

[0135] The constant voltage control of the primary full-bridge circuit is achieved according to the constant voltage phase shift angle through the PID control circuit.

[0136] Please note that Figure 7, theoretically speaking, the output voltage of the primary circuit of the phase-shift control should be as follows:

[0137]

[0138] But when the load resistance When the change occurs, the equivalent load resistance of the system will also change, and the system cannot achieve constant current or constant voltage output. Therefore, this embodiment analyzes the conditions for constant current or constant voltage output control and designs specific constant current or constant voltage output control parameters.

[0139] Specifically, the output voltage formula of the above phase shift control primary circuit is expanded by Fourier series to obtain:

[0140]

[0141] Since the transmitting end has a filtering effect after resonance, the output voltage The harmonic components can be filtered out, so the output voltage Valid values ​​are:

[0142]

[0143] Among them, the phase shift angle The value range is .

[0144] In the case of achieving ZVS zero voltage control, if the load resistance value is changes, the output voltage of the system circuit and output current It needs to remain constant, so this embodiment ensures that the system can maintain a constant current or constant voltage output effect when the load resistance value changes through the size of the physical phase shift angle.

[0145] For constant current: introduce constant current coefficient , the output current of the primary full-bridge circuit after phase shift control is Output current with load The relationship between them is:

[0146]

[0147] It is understandable that the system input current It is the output current of the primary full-bridge circuit after phase shift control. , and the load output current is the output current of the system circuit ; And this formula is the condition for achieving constant current output. Combining the above equivalent equation for theoretical analysis, the constant current coefficient can be determined Expression:

[0148]

[0149] Assume that the constant voltage and constant current values ​​required by the system are , , then the above current relationship formula can be used according to the collected system input current Calculate the actual load current output value, that is, the first load output current value, which can be expressed as Then the actual load voltage output value is collected through the voltage collection circuit, that is, the first load output voltage value, which is recorded as , then the load resistance value at this moment can be calculated through the DSP control circuit size, and then and By comparison, the new phase shift angle can be calculated, that is, the constant current phase shift angle :

[0150]

[0151] The PID control circuit is used to control the phase angle according to the constant current The phase shift angle of the primary circuit can be adjusted to achieve a fixed current output for the topological load.

[0152] For constant pressure: introduce constant pressure coefficient , the output current of the primary full-bridge circuit after phase shift control is Output voltage with load The relationship between them is:

[0153]

[0154] Similarly, this formula is the condition for achieving constant voltage output. Combining the above equivalent equation for theoretical analysis, the constant voltage coefficient can be determined Expression:

[0155]

[0156] Based on the above current-voltage relationship, the system input current collected The load current output value at this moment can be calculated, that is, the second load output current value, which is recorded as Then the actual load voltage output value is collected through the voltage collection circuit, that is, the second load output voltage value, which is recorded as , then the load resistance value at this moment can be calculated through the DSP control circuit size, and then and By comparison, the constant voltage phase shift angle can be calculated :

[0157]

[0158] The PID control circuit is used to control the phase angle according to the constant voltage The phase shift angle of the primary circuit can be adjusted to achieve a fixed voltage output for the topological load. It is the phase shift conduction angle.

[0159] For ease of understanding, take the input DC power supply 200V, operating frequency 85kHz, transmitting coil And the receiving coil The initial load resistance value is 190μH. is 22.5Ω, the initial phase shift conduction angle Set to 40. The detuning factor introduced , the mutual inductance between the transmitting coil and the receiving coil =66.5μH, resonant inductance =150μH and coefficient =1.53, =34.45 as an example, keep the load output current at 4.3A and the load output voltage at 97V. When the load resistance changes from 15Ω to 30Ω during charging, the phase shift conduction angle in different modes ( and ) and the load resistance value are as follows Figure 8 In the constant current output mode, by changing the constant current phase shift conduction angle Keep the output current of the load at about 4.3A. Fig. 9 In constant voltage output mode, by changing the constant voltage phase shift conduction angle The output voltage of the load is maintained at about 97V. Fig. 9 At the same time, the phase shift conduction angle in two different modes is given. With load resistance value Change relationship diagram.

[0160] The wireless power transmission control method with controllable output provided in the embodiment of the present application realizes the wireless power transmission control of zero voltage opening of MOSFET switch tube by combining the designed control circuit with the control method, and the phase shift control under the detuning condition is considered in this process; the equivalent input impedance angle used to drive the ZVS zero voltage opening control is determined based on the equivalent simplified circuit and parameter calculation, and the wireless power transmission control process is limited by the detuning value constraint and the impedance value constraint, which can ensure that this process is more in line with the actual situation and the control effect is more accurate and reliable; and the circuits and operations involved in the process are simple and easy to execute, which can meet the control requirements of actual application scenarios. Therefore, the embodiment of the present application can solve the technical problems that the circuit topology structure and the zero voltage opening control method of the prior art are relatively complex, cannot meet the actual scene control requirements, and will increase the difficulty of system maintenance.

[0161] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0162] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0163] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0164] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium, including a number of instructions for executing all or part of the steps of the method described in each embodiment of the present application through a computer device (which can be a personal computer, server, or network device, etc.). The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (full name in English: Read-Only Memory, English abbreviation: ROM), random access memory (full name in English: Random Access Memory, English abbreviation: RAM), disk or optical disk and other media that can store program codes.

[0165] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A control method for wireless power transmission with controllable output, characterized in that: The control method is implemented by a control circuit, which includes: a primary full-bridge circuit, an LCC-S compensation network, a secondary uncontrolled rectifier circuit, a sampling circuit and a control circuit; The primary full-bridge circuit includes four MOSFET switch tubes, and two of the MOSFET switch tubes constitute a primary bridge arm, and ZVS zero voltage switching is achieved based on phase shift control; The LCC-S compensation network includes a primary coil, a primary compensation inductor and a primary compensation capacitor, wherein the primary compensation inductor and two primary compensation capacitors are connected in parallel to form a T-type structure; The secondary side uncontrolled rectifier circuit includes a secondary side full bridge circuit and a secondary side compensation network; The sampling circuit is used to collect the current of the primary full-bridge circuit and the voltage of the secondary full-bridge circuit; The control circuit includes a PWM drive circuit, a PID control circuit and a DSP control circuit, which are used to control wireless power transmission; The control method comprises: Constructing an equivalent simplified circuit for the control circuit and setting initial parameters; Analyzing the equivalent simplified circuit based on the fundamental wave approximation method, and constructing a voltage and current equivalent equation according to the initial parameters; Introducing a detuning coefficient, performing a detuning analysis on the equivalent simplified circuit according to the voltage-current equivalent equation, and calculating the detuning coefficient to obtain a calculated value of the detuning coefficient; Calculating the equivalent input impedance angle of the primary circuit according to the calculated value of the detuning coefficient; Based on the detuning value constraint and the impedance value constraint, the ZVS zero voltage switching control is driven according to the equivalent input impedance angle to realize wireless power transmission control.

2. The control method for wireless power transmission with controllable output according to claim 1, characterized in that: The first MOSFET switch tube and the second MOSFET switch tube in the primary full-bridge circuit constitute a primary super forearm; The third MOSFET switch tube and the fourth MOSFET switch tube constitute a primary side lagging arm; The ZVS zero voltage switching of the MOSFET switch tubes of the primary leading arm and the primary lagging arm is controlled by a preset phase shift angle.

3. The control method for wireless power transmission with controllable output according to claim 1, characterized in that: One end of the primary coil in the LCC-S compensation network is connected in series with a primary compensation capacitor and a primary compensation inductor, and then connected to the positive end of the middle point of the primary bridge arm in the primary full-bridge circuit; The other end of the primary coil in the LCC-S compensation network is connected to the negative end of the midpoint of the primary bridge arm in the primary full-bridge circuit.

4. The control method for wireless power transmission with controllable output according to claim 1, characterized in that: The secondary full-bridge circuit includes four symmetrical diodes, and the output ends are connected in parallel with the filter capacitor and the load respectively; The secondary compensation network includes a receiving coil and a secondary compensation capacitor, and the secondary compensation network is connected to the midpoint of the secondary bridge arm in the secondary full-bridge circuit.

5. The control method for wireless power transmission with controllable output according to claim 1, characterized in that: The DSP control circuit generates a PID control instruction according to the current and the voltage collected by the sampling circuit; The PID control circuit generates a conduction angle according to the PID control instruction, and triggers the PWM drive circuit to drive the operation of the primary full-bridge circuit through the conduction angle.

6. The control method for wireless power transmission with controllable output according to claim 1, characterized in that: The introducing of the detuning coefficient, performing a detuning analysis on the equivalent simplified circuit according to the voltage-current equivalent equation, and calculating the detuning coefficient to obtain a calculated value of the detuning coefficient includes: A detuning coefficient is introduced to perform resonance adjustment on the voltage-current equivalent equation to obtain a resonance equivalent relationship equation; A detuning analysis is performed on the equivalent simplified circuit according to the resonance equivalent relationship equation, and the detuning coefficient is calculated to obtain a detuning coefficient calculation value.

7. The control method for wireless power transmission with controllable output according to claim 1, characterized in that: The introducing of the detuning coefficient, performing a detuning analysis on the equivalent simplified circuit according to the voltage-current equivalent equation, and calculating the detuning coefficient to obtain a calculated value of the detuning coefficient also includes: Constructing an output power expression of the system according to the detuning coefficient; The detuning coefficient is differentiated according to the output power expression, the detuning coefficient is calculated when the partial derivative value is 0, and a detuning coefficient reference value is obtained.

8. The control method for wireless power transmission with controllable output according to claim 1, characterized in that: The calculating the equivalent input impedance angle of the primary circuit according to the calculated value of the detuning coefficient includes: Calculating the equivalent input impedance of the primary circuit according to the calculated value of the detuning coefficient and the secondary primary reflected impedance value; An equivalent input impedance angle of the primary circuit is determined according to the equivalent input impedance.

9. The control method for wireless power transmission with controllable output according to claim 1, characterized in that: The method drives the ZVS zero voltage switching control based on the detuning value constraint and the impedance value constraint according to the equivalent input impedance angle to realize the wireless power transmission control, and further includes: When the load resistance value changes, a constant current coefficient is introduced to calculate the output current value of the first load, and the output voltage value of the first load is collected, wherein the constant current coefficient is calculated according to the constant current condition; Calculating a constant current phase shift angle of the primary full-bridge circuit according to the first load output current value and the first load output voltage value; The PID control circuit realizes constant current control of the primary full-bridge circuit according to the constant current phase shift angle.

10. The control method for wireless power transmission with controllable output according to claim 1, characterized in that: The method drives the ZVS zero voltage switching control based on the detuning value constraint and the impedance value constraint according to the equivalent input impedance angle to realize the wireless power transmission control, and further includes: When the load resistance value changes, a constant voltage coefficient is introduced to calculate the second load output current value, and the second load output voltage value is collected, wherein the constant voltage coefficient is calculated according to the constant voltage condition; Calculating a constant voltage phase shift angle of the primary full-bridge circuit according to the second load output current value and the second load output voltage value; The PID control circuit realizes constant voltage control on the primary full-bridge circuit according to the constant voltage phase shift angle.

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