CN114243945A - Wireless charging system and resonant network matching method thereof - Google Patents
Wireless charging system and resonant network matching method thereof Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
- H02J50/10—Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling
- H02J50/12—Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling of the resonant type
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0047—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with monitoring or indicating devices or circuits
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Abstract
The application relates to a wireless charging system and a resonant network matching method thereof, wherein the system comprises an inverter and a primary side series inductor LfPrimary side series capacitor C1Wireless charging primary coil L1And a wireless charging secondary coil L2Secondary side series capacitor C2A secondary rectifier bridge, a data acquisition device, a controller and a primary side series capacitor C1And secondary side series capacitor C2Is a switched capacitor. When the relative position of the coil changes, the phase difference value is calculated by detecting the corresponding voltage and current amount in the wireless charging system, and then the duty ratio of the PWM pulse signal for controlling the switch capacitor is adjusted, so that the change of the coil self-inductance in the wireless charging system is adapted, the system is constantly in a resonance state, and the transmission power and the transmission efficiency of the wireless charging system are improved.
Description
Technical Field
The application relates to the technical field of power grids, in particular to a wireless charging system and a resonant network matching method thereof.
Background
Compared with the traditional contact type electric energy transmission mode, the wireless electric energy transmission mode does not need cables or other physical connections, so that the charging environment is more attractive and tidy, and the safety problems of line aging, poor contact, contact sparks and the like are solved. The inductive coupling type wireless power transmission technology utilizes the near field coupling of a medium-low frequency electromagnetic field to realize wireless power transmission based on an electromagnetic induction coupling principle, has the characteristics of high transmission power and high transmission efficiency, and has wide application scenes. When the primary coil and the secondary coil deviate, namely the relative position changes, the resonance condition is not satisfied any more, the reactive power component of the system is increased, and the output power and the efficiency are reduced.
Disclosure of Invention
Accordingly, it is desirable to provide a wireless charging system and a resonant network matching method thereof, which can maintain a resonant state when the relative position of the coil changes, thereby improving the transmission power and transmission efficiency of the wireless charging system.
A wireless charging system comprises an inverter and a primary side series inductor LfPrimary side series capacitor C1Wireless charging primary coil L1And a wireless charging secondary coil L2Secondary side series capacitor C2A secondary rectifier bridge, a data acquisition device and a controller, wherein the primary side is connected with a capacitor C in series1And the secondary side is connected with a capacitor C in series2Is a switched capacitor; the inverter is connected with a direct current voltage source and the primary side series inductor LfThe primary side series inductance LfConnecting the primary side series capacitor C1The primary side is connected in series with a capacitor C1Connect the wireless charging primary coil L1The first end of the wireless charging primary coil L1The second end of the inverter is connected with the inverter; the wireless charging secondary coil L2Is connected with the secondary side series capacitor C2The secondary side is connected in series with a capacitor C2Connect the secondary rectifier bridge, the wireless secondary coil L that charges2The second end of the secondary side rectifier bridge is connected with the secondary side rectifier bridge; the controller is connected with the data acquisition device and the primary side series capacitor C1And the secondary side is connected with a capacitor C in series2；
The data acquisition device is used for acquiring voltage and current data and sending the voltage and current data to the controller, and the controller is used for calculating phase difference data according to the current and voltage data and controlling and outputting the phase difference data to the primary side series capacitor C according to the phase difference data1And the secondary side is connected with a capacitor C in series2The duty ratio of the PWM pulse signal of (1) and the primary side series capacitor C1And the secondary side is connected with a capacitor C in series2So that the wireless charging system is resistive and in a resonance state.
In one embodiment, the data acquisition device comprises a first current sensor, a second current sensor, a first voltage sensor and a second voltage sensor, wherein the first current sensor is used for detecting the output current of the inverter and sending the output current to the controller, and the first voltage sensor is used for detecting the output voltage of the inverter and sending the output voltage to the controller; the second current sensor is used for detecting the primary side series capacitor C1And the wireless charging primary coil L1The second voltage sensor is used for detecting the secondary side series capacitor C2And the voltage at the two ends is sent to the controller.
In one embodiment, the switched capacitor comprises a capacitor Cm1Capacitor Cs1Capacitor Cp1And a switching tube Qp1And a switching tube Qs1Said capacitor Cp1And the switching tube Qp1Is connected with the capacitor Cm1In parallel, the switching tube Qs1And the capacitor Cs1In parallel, and the switching tube Qs1First end of and the switching tube Qp1Is connected with the second end of the first end; the switch tube Qp1And said switching tube Qs1Is connected with the controller.
In one embodiment, the switch tube Qp1And said switching tube Qs1Are all MOS tubes.
In one embodiment, the inverter comprises a switch tube T1Switch tube T2Switch tube T3And a switching tube T4Said switch tube T1And said switching tube T3The first end of the switch tube T is connected with the positive electrode of the direct-current voltage source after being connected, and the switch tube T1Second end of and the switching tube T2Is connected with the primary side series inductor LfConnection, the switching tube T3And said switching tube T4Is connected with the wireless charging primary coil L1Is connected with the second end of the switch tube T2And said switching tube T4And the second end of the second switch is connected with the negative electrode of the direct-current voltage source.
In one embodiment, the secondary side rectifier bridge comprises a diode D1Diode D2Diode D3And a diode D4Said diode D1And the diode D2After being connected with the cathode, the cathode of the capacitor is connected with the secondary side in series with a capacitor C2Connected, the diode D3And the diode D4After being connected with the cathode, the cathode is connected with the wireless charging secondary coil L2Is connected to the second terminal of the diode D1And said diode D3The cathode of the diode D is connected with the first output end of the secondary side rectifier bridge2And the diode D4And the anode of the secondary rectifier bridge is connected to be used as a second output end of the secondary rectifier bridge.
In one embodiment, the wireless charging system further comprises an output capacitor CdSaid output capacitor CdOne end of the output capacitor C is connected with the first output end of the secondary side rectifier bridgedThe other end of the secondary side rectifier bridge is connected with a second output end of the secondary side rectifier bridge.
In one of themIn one embodiment, the wireless charging system further comprises a primary side parallel capacitor CfThe primary side is connected with a capacitor C in parallelfOne end of which is connected with the primary side series inductor LfAnd the primary side series capacitor C1The primary side parallel capacitor CfThe other end of the primary coil is connected with the wireless charging coil L1The second end of (a).
A wireless charging system resonant network matching method is realized based on the wireless charging system, and the method comprises the following steps:
receiving current and voltage data sent by a data acquisition device, and calculating according to the current and voltage data to obtain phase difference data;
controlling the output to the primary side series capacitor C according to the phase difference data1And secondary side series capacitor C2The duty ratio of the PWM pulse signal of (1) and the primary side series capacitor C1And the secondary side is connected with a capacitor C in series2So that the wireless charging system is resistive and in a resonance state.
In one embodiment, the control output to the primary side series capacitor C is controlled according to the phase difference data1And secondary side series capacitor C2The duty ratio of the PWM pulse signal of (1) is: regulating and outputting the phase difference data to the primary side series capacitor C by using PI (proportional integral) control1And the secondary side is connected with a capacitor C in series2Duty ratio of the PWM pulse signal.
The wireless charging system and the resonant network matching method thereof, and the primary side series capacitor C1And secondary side series capacitor C2Adopting a switch capacitor, calculating according to the voltage and current data acquired by the data acquisition device to obtain phase difference data, and controlling and outputting to the primary side series capacitor C according to the phase difference data1And secondary side series capacitor C2The duty ratio of the PWM pulse signal of (1) and the primary side series capacitor C1And secondary side series capacitor C2So that the wireless charging system is resistive and in a resonance state. When the relative position of the coil changes, the phase difference value is calculated by detecting the corresponding voltage and current amount in the wireless charging system, and then the PWM pulse for controlling the switch capacitor is adjustedThe duty ratio of the signal is adjusted to the change of coil self-inductance in the wireless charging system, so that the system is in a resonance state at all times, and the transmission power and the transmission efficiency of the wireless charging system are improved.
Drawings
Fig. 1 is an equivalent circuit diagram of a wireless charging system according to an embodiment;
FIG. 2 is a schematic diagram of a switched capacitor in one embodiment;
fig. 3 is an equivalent circuit diagram of an LCC/S type wireless power transmission system according to an embodiment.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or be connected to the other element through intervening elements. The "connection" in the following embodiments is understood as "electrical connection", "communication connection", or the like if the connected circuits, modules, units, or the like have electrical signals or data transmission therebetween.
As used herein, the singular forms "a", "an" and "the" may include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises/comprising," "includes" or "including," etc., specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. Also, the terminology used in this specification includes any and all combinations of the associated listed items.
In one embodiment, as shown in fig. 1, a wireless charging system is provided, which includes an inverter 100, a primary side series inductor LfPrimary side series capacitor C1Wireless charging primary coil L1And a wireless charging secondary coil L2Secondary side series capacitor C2A secondary rectifier bridge 200, a data acquisition device, a controller and a primary side series capacitor C1And secondary side series capacitor C2Is a switched capacitor. The inverter 100 is connected to a DC voltage source VdcAnd primary side series inductance LfPrimary side series inductance LfConnecting primary side series capacitor C1Primary side series capacitor C1Connect wireless primary coil L that charges1First terminal of (1), wireless charging primary coil L1Is connected to the inverter 100; wireless secondary coil L that charges2The first end of the capacitor is connected with a secondary side series capacitor C2Secondary side series capacitor C2A secondary rectifier bridge 200 connected with the secondary coil L for wireless charging2The second end of the secondary rectifier bridge 200; the controller is connected with a data acquisition device and a primary side series capacitor C1And secondary side series capacitor C2。
In FIG. 1, the resistor RfRepresenting the primary side series inductance LfInternal resistance of, resistance R1Primary coil L for wireless charging1Internal resistance of, resistance R2Secondary coil L for wireless charging2Internal resistance of (2). The controller may specifically be a DSP (Digital Signal Processing) controller. The data acquisition device is used for acquiring voltage and current data and sending the voltage and current data to the controller, and the controller is used for calculating according to the current and voltage data to obtain phase difference data and controlling and outputting the phase difference data to the primary side series capacitor C according to the phase difference data1And secondary side series capacitor C2The duty ratio of the PWM pulse signal of (1) and the primary side series capacitor C1And secondary side series capacitor C2So that the wireless charging system is resistive and in a resonance state. Wherein, the controller outputs a pulse signal PWM1 to the primary side series capacitor C1Regulating the originalSide series capacitor C1The controller outputs a pulse signal PWM2 to the secondary side series capacitor C2Adjusting secondary side series capacitance C2The capacitance value of (2).
Specifically, in one embodiment, with continued reference to fig. 1, the data acquisition device includes a first current sensor for detecting the output current I of the inverter 100, a second current sensor, a first voltage sensor, and a second voltage sensorin_acAnd sent to a controller, and a first voltage sensor for detecting an output voltage U of the inverter 100in_acAnd sending to the controller; the second current sensor is used for detecting the primary side series capacitor C1And a wireless charging primary coil L1Current I between1And sent to the controller, and a second voltage sensor for detecting secondary side series capacitor C2Voltage U acrossc2And sent to the controller. The first current sensor, the second current sensor, the first voltage sensor and the second voltage sensor can all adopt Hall sensors.
Correspondingly, the Controller performs data analysis according to the corresponding voltage and current signals in the circuit detected by the hall sensor to obtain corresponding phase difference signals, and then the corresponding phase difference signals can be obtained by controlling the PWM pulse signals of the switch tube in the switch capacitor structure through a PI (Proportional Integral Controller) to obtain corresponding equivalent capacitors, so that the whole wireless charging system is resistive, the system is in resonance, and the wireless charging system is ensured to keep the maximum output voltage and transmission efficiency when the coil is deviated. The controller can pre-store the corresponding relation between the phase difference and the capacitance value adjusting amplitude, after the actual phase difference is obtained through calculation according to actually acquired voltage and current signals, the capacitance value adjusting amplitude needing to be adjusted can be determined according to the stored corresponding relation, then the duty ratio of the PWM pulse signal is changed through PI control, and the capacitance values of the two switch capacitors are changed.
The particular configuration of the switched capacitor is not exclusive and in one embodiment, as shown in FIG. 2, the switched capacitor comprises a capacitor Cm1Capacitor Cs1Capacitor Cp1And a switching tube Qp1And a switching tube Qs1Capacitor Cp1And a switching tube Qp1Is connected with the capacitor C after being connected with the first endm1Parallel connected, switch tube Qs1And a capacitor Cs1Connected in parallel and the switching tube Qs1First end of and a switch tube Qp1Is connected with the second end of the first end; switch tube Qp1Control terminal and switching tube Qs1The control end of the controller is connected with the controller. Wherein, the switch tube Qp1And a switching tube Qs1The switch tube can be a triode or a MOS tube for controlling, in this embodiment, the switch tube Qp1And a switching tube Qs1Are all MOS tubes.
In particular, the capacitance Cp1One end of and a switching tube Qp1Is connected in series with the capacitor C as a wholem1Parallel connected, switch tube Qp1Drain of and the switching tube Qs1Source electrode of (1) is connected with a switching tube Qs1And a capacitor Cs1And (4) connecting in parallel. Wherein, the capacitor Cm1One terminal of and a capacitor Cs1Is connected to a capacitor Cm1Another terminal of (1) and a capacitor Cs1And the other end of the same is used for accessing the circuit. Switch tube Qp1Grid and switching tube Qs1The grid electrodes of the grid electrodes are all connected with a controller, and the controller sends the grid electrodes to a switching tube Q through changep1Grid and switching tube Qs1The duty ratio of the PWM pulse signal to the gate, thereby changing the equivalent capacitance of the switched capacitor.
In one embodiment, with continued reference to fig. 1, inverter 100 includes a switching tube T1Switch tube T2Switch tube T3And a switching tube T4Switch tube T1First end of and a switching tube T3Is connected with a direct voltage source VdcIs connected with the positive pole of the switch tube T1Second terminal and switching tube T2Is connected with the primary side series inductor LfConnecting and switching tube T3Second terminal and switching tube T4Is connected with the wireless charging primary coil L1Is connected with the second end of the switch tube T2Second terminal and switching tube T4Is connected with a DC voltage source V after the second end of the DC voltage source V is connected withdcIs connected to the negative electrode of (1).In addition, the controller can be connected with a switch tube T1Switch tube T2Switch tube T3And a switching tube T4By controlling the switching tube T1Switch tube T2Switch tube T3And a switching tube T4So that the inverter 100 converts the direct voltage source V intodcAnd carrying out inversion processing on the output direct current to obtain alternating current. Wherein, the switch tube T1Switch tube T2Switch tube T3And a switching tube T4MOS transistors may be used.
In one embodiment, the wireless charging system further comprises a primary side parallel capacitor CfPrimary side parallel capacitor CfOne end of which is connected with a primary side series inductor LfAnd a primary side series capacitor C1Is connected in parallel with a capacitor C on the primary sidefThe other end of the primary coil L is connected with the wireless charging coil1The second end of (a).
In one embodiment, secondary side rectifier bridge 200 includes diode D1Diode D2Diode D3And a diode D4Diode D1Anode of (2) and diode D2After the cathode is connected, the capacitor C is connected with the secondary side in series2Connected, diode D3And diode D4The cathode is connected with a wireless charging secondary coil L2Is connected to the second terminal of diode D1Cathode and diode D3Is connected as a first output terminal of the secondary rectifier bridge 200, and a diode D2Anode of (2) and diode D4And then serves as a second output terminal of the secondary rectifier bridge 200. The first output end and the second output end of the secondary rectifier bridge 200 are used for connecting load equipment, and the secondary rectifier bridge 200 rectifies the induced alternating current and outputs the direct current to supply power to the load equipment.
In addition, in one embodiment, the wireless charging system further comprises an output capacitor CdOutput capacitance CdIs connected to the first output terminal of the secondary rectifier bridge 200, and outputs a capacitor CdAnd the other end thereof is connected to a second output terminal of the secondary rectifier bridge 200. Output capacitor CdDirect current capable of being output to secondary side rectifier bridge 200And voltage stabilization is performed, and the power supply stability is improved.
Above-mentioned wireless charging system, when coil relative position changes appears, calculates the phase difference value through detecting corresponding voltage amperage among the wireless charging system, and then adjusts the duty cycle of the PWM pulse signal of control switch capacitor to coil self-inductance's change in the adaptation wireless charging system makes the system constantly be in resonance state, and then promotes wireless charging system's transmission power and transmission efficiency.
In an embodiment, a wireless charging system resonant network matching method is further provided, and is implemented based on the wireless charging system, and the method includes: receiving current and voltage data sent by a data acquisition device, and calculating according to the current and voltage data to obtain phase difference data; controlling the output to the primary side series capacitor C according to the phase difference data1And secondary side series capacitor C2The duty ratio of the PWM pulse signal of (1) and the primary side series capacitor C1And secondary side series capacitor C2So that the wireless charging system is resistive and in a resonance state.
In one embodiment, the output to the primary side series capacitor C is controlled according to the phase difference data1And secondary side series capacitor C2The duty ratio of the PWM pulse signal of (1) is: regulating and outputting to a primary side series capacitor C by using PI control according to phase difference data1And secondary side series capacitor C2Duty ratio of the PWM pulse signal.
According to the wireless charging system resonant network matching method, when the relative position of the coil changes, the phase difference value is calculated by detecting the corresponding voltage and current amount in the wireless charging system, and then the duty ratio of the PWM pulse signal for controlling the switch capacitor is adjusted, so that the change of the coil self-inductance in the wireless charging system is adapted, the system is in a resonant state at all times, and the transmission power and the transmission efficiency of the wireless charging system are improved.
In order to better understand the wireless charging system and the resonant network matching method thereof, the following detailed description is made with reference to specific embodiments.
The inductive coupling type wireless power transmission technology utilizes the near field coupling of a medium-low frequency electromagnetic field to realize wireless power transmission based on an electromagnetic induction coupling principle, has the characteristics of high transmission power and high transmission efficiency, and has wide application scenes. The LCC/S type compensation topology has the characteristics of constant current on the primary side and constant output voltage on the secondary side, and is widely applied to a wireless charging system.
Fig. 3 is an equivalent circuit diagram of an LCC/S type wireless power transmission system according to the present application. In the wireless charging system, there are three sets of resonance conditions in total:
when these three sets of resonance conditions are satisfied, the system output power and efficiency reach maximum values. When the primary coil and the secondary coil are deviated, namely the relative positions are changed, the mutual inductance M and the self-inductance L of the two coils1And L2Changes will occur. When the mutual inductance of the coil changes, the output voltage of the system changes. When self-inductance L1And L2When the resonance condition is changed, the resonance condition is not satisfied any more, the reactive power component of the system is increased, and the output power and the efficiency are reduced.
To keep the wireless charging system in a resonant state, the industry mainly starts from the aspects of frequency conversion and capacitance transformation to adapt to the coil self-inductance L1And L2The change of (c) brings the system to a resonance state at a moment. Regarding the frequency conversion method, because the resonance conditions used in the LCC/S topology are many, the resonance conditions in the system cannot be satisfied by using the frequency conversion method alone. With respect to the method of varying the capacitance, by varying the capacitance C1And C2To adapt the coil inductance L1And L2It is a feasible solution to bring the system to resonance again.
At present, devices related to variable capacitance mainly include capacitor matrix and voltage control type capacitor. The capacitor matrix realizes the change of the capacitance value by switching the parallel weighted binary capacitance, but the capacitance changing mode cannot realize the continuous adjustment of the capacitance value and needs a plurality of switches and capacitors. The voltage control type capacitor controls the conduction time of the diode by controlling the base current and the collector current of the triode, thereby adjusting the size of the parallel resonance capacitor. But the variable capacitance approach is only suitable for low power application scenarios.
Based on this, the application provides a method that can make the wireless charging system maintain the resonance state when the relative position of the coil changes by using the switched capacitor, thereby improving the transmission power and the transmission efficiency of the wireless charging system.
As shown in fig. 1, the circuit components of the wireless charging system include: DC voltage source VdcFour switching tubes T1、T2、T3、T4Formed inverter and primary side series inductor LfPrimary side parallel capacitor CfPrimary side series capacitor C1Wireless charging primary coil L1And a wireless charging secondary coil L2Secondary side series capacitor C2A secondary rectifier bridge and a load resistor R. DC voltage source VdcA primary side series inductor L is connected in series after passing through an inverterfThen connected in parallel with a primary side parallel capacitor CfPrimary side parallel capacitor CfOne end of which is connected with a primary side series capacitor C1Primary side of the primary side series capacitor C1Is connected to the wireless charging primary coil L at the other end1One end of (1), a wireless charging primary coil L1Is connected at the other end to a primary side parallel capacitor CfAnd the other end of the same. Wireless secondary coil L that charges2A capacitor C connected in series with the secondary side2And the direct current side behind the secondary side rectifier bridge is connected with a resistance load R. Resistance RfRepresenting the primary side series inductance LfInternal resistance of, resistance R1Representing wirelessCharging primary coil L1Internal resistance of, resistance R2Secondary coil L for wireless charging2Internal resistance of (2).
Wherein, the primary side is connected in series with a capacitor C1And secondary side series capacitor C2The switched capacitor structure is adopted to adapt to the change of coil self-inductance, so that the matching of a coil resonance network is realized, and a system is in a resonance state at all times.
The switched capacitor structure: the series-parallel connection switching is carried out on the switch tube and the capacitor, and the series-parallel connection proportion is controlled to change the equivalent capacitor, so that the change of the capacitance value is realized. The capacitor structure can realize the change of the capacitance value within a larger range. As shown in fig. 2, the specific circuit connection manner of the switched capacitor is as follows: capacitor Cp1One end of and a switching tube Qp1Is connected in series with the capacitor C as a wholem1Parallel connected, switch tube Qp1Drain of and the switching tube Qs1Source electrode of (1) is connected with a switching tube Qs1And a capacitor Cs1And (4) connecting in parallel.
The self-adaptive resonance implementation method comprises the following steps:
when the wireless charging system is in a resonance state, the whole circuit can present pure resistance; when the system is not in resonance, the circuit may exhibit capacitive or inductive characteristics. Therefore, the phase difference between the corresponding voltage signal and the current signal of the wireless charging system is detected to judge whether the system is in a resonance state. The capacitance value is controlled by controlling the conduction proportion of a switch tube in the switch capacitor structure, so that the change of coil self-inductance in a wireless charging system is adapted, and the system is in a resonance state at any time.
The method comprises the following specific implementation steps:
the Hall sensor is used for detecting to obtain corresponding voltage and current signals in the circuit, the signals are processed and sent to the DSP, data analysis is carried out on the signals in the DSP to obtain corresponding phase difference signals, and then the PWM pulse signals for controlling the switch tube in the switch capacitor structure are obtained through PI control to obtain corresponding equivalent capacitors, so that the whole wireless charging system is resistive, the purpose that the system is in resonance is achieved, and the wireless charging system is guaranteed to keep the maximum output voltage and transmission efficiency when a coil deflects.
The method for enabling the wireless charging system to be maintained in the resonance state when the relative position of the coil changes by using the switched capacitor aims at the problems that the self-inductance change caused by the change of the relative position of the coil in the wireless charging system causes the system detuning and the output power and the transmission efficiency of the wireless charging system are reduced, and the primary side series capacitor C is connected with the primary side series capacitor C1And secondary side series capacitor C2A switched capacitor with a variable capacitance value is used instead of a capacitor with a fixed capacitance value. The phase difference is obtained by detecting corresponding voltage and current signals in the wireless charging system, the phase difference is controlled to be zero by the PI, the PWM signal for controlling a switch tube in a switch capacitor is obtained by calculation, the adjustment of two resonance capacitance values is realized by adjusting the conduction proportion of the switch tube of the switch capacitor, and the system is in a resonance state at any time by adapting to the change of self-inductance through the change of the capacitance values, so that the purposes of improving the output power and the transmission efficiency of the system are achieved.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. A wireless charging system is characterized by comprising an inverter and a primary side series inductor LfPrimary side series capacitor C1Wireless charging primary coil L1And a wireless charging secondary coil L2Secondary side series capacitor C2Secondary side rectifier bridge, dataA collection device and a controller, the primary side series capacitor C1And the secondary side is connected with a capacitor C in series2Is a switched capacitor; the inverter is connected with a direct current voltage source and the primary side series inductor LfThe primary side series inductance LfConnecting the primary side series capacitor C1The primary side is connected in series with a capacitor C1Connect the wireless charging primary coil L1The first end of the wireless charging primary coil L1The second end of the inverter is connected with the inverter; the wireless charging secondary coil L2Is connected with the secondary side series capacitor C2The secondary side is connected in series with a capacitor C2Connect the secondary rectifier bridge, the wireless secondary coil L that charges2The second end of the secondary side rectifier bridge is connected with the secondary side rectifier bridge; the controller is connected with the data acquisition device and the primary side series capacitor C1And the secondary side is connected with a capacitor C in series2；
The data acquisition device is used for acquiring voltage and current data and sending the voltage and current data to the controller, and the controller is used for calculating phase difference data according to the current and voltage data and controlling and outputting the phase difference data to the primary side series capacitor C according to the phase difference data1And the secondary side is connected with a capacitor C in series2The duty ratio of the PWM pulse signal of (1) and the primary side series capacitor C1And the secondary side is connected with a capacitor C in series2So that the wireless charging system is resistive and in a resonance state.
2. The wireless charging system according to claim 1, wherein the data acquisition device comprises a first current sensor, a second current sensor, a first voltage sensor and a second voltage sensor, the first current sensor is configured to detect an output current of the inverter and transmit the output current to the controller, and the first voltage sensor is configured to detect an output voltage of the inverter and transmit the output voltage to the controller; the second current sensor is used for detecting the primary side series capacitor C1And the wireless charging primary coil L1And the second voltage sensor is used for detecting the secondary side stringCoupling capacitor C2And the voltage at the two ends is sent to the controller.
3. The wireless charging system of claim 1, wherein the switched capacitor comprises a capacitor Cm1Capacitor Cs1Capacitor Cp1And a switching tube Qp1And a switching tube Qs1Said capacitor Cp1And the switching tube Qp1Is connected with the capacitor Cm1In parallel, the switching tube Qs1And the capacitor Cs1In parallel, and the switching tube Qs1First end of and the switching tube Qp1Is connected with the second end of the first end; the switch tube Qp1And said switching tube Qs1Is connected with the controller.
4. The wireless charging system of claim 3, wherein the switching tube Qp1And said switching tube Qs1Are all MOS tubes.
5. The wireless charging system of claim 1, wherein the inverter comprises a switching tube T1Switch tube T2Switch tube T3And a switching tube T4Said switch tube T1And said switching tube T3The first end of the switch tube T is connected with the positive electrode of the direct-current voltage source after being connected, and the switch tube T1Second end of and the switching tube T2Is connected with the primary side series inductor LfConnection, the switching tube T3And said switching tube T4Is connected with the wireless charging primary coil L1Is connected with the second end of the switch tube T2And said switching tube T4And the second end of the second switch is connected with the negative electrode of the direct-current voltage source.
6. The wireless charging system of claim 1, wherein the secondary rectifier bridge comprises a diode D1Diode D2Diode D3And a diode D4Said diode D1And the diode D2After being connected with the cathode, the cathode of the capacitor is connected with the secondary side in series with a capacitor C2Connected, the diode D3And the diode D4After being connected with the cathode, the cathode is connected with the wireless charging secondary coil L2Is connected to the second terminal of the diode D1And said diode D3The cathode of the diode D is connected with the first output end of the secondary side rectifier bridge2And the diode D4And the anode of the secondary rectifier bridge is connected to be used as a second output end of the secondary rectifier bridge.
7. The wireless charging system of claim 6, further comprising an output capacitor CdSaid output capacitor CdOne end of the output capacitor C is connected with the first output end of the secondary side rectifier bridgedThe other end of the secondary side rectifier bridge is connected with a second output end of the secondary side rectifier bridge.
8. The wireless charging system of any one of claims 1-7, further comprising a primary side parallel capacitor CfThe primary side is connected with a capacitor C in parallelfOne end of which is connected with the primary side series inductor LfAnd the primary side series capacitor C1The primary side parallel capacitor CfThe other end of the primary coil is connected with the wireless charging coil L1The second end of (a).
9. A wireless charging system resonant network matching method, implemented based on the wireless charging system of any one of claims 1 to 8, the method comprising:
receiving current and voltage data sent by a data acquisition device, and calculating according to the current and voltage data to obtain phase difference data;
controlling the output to the primary side series capacitor C according to the phase difference data1And secondary side series capacitor C2The duty ratio of the PWM pulse signal of (1) and the primary side series capacitor C1And saidSecondary side series capacitor C2So that the wireless charging system is resistive and in a resonance state.
10. The method of claim 9, wherein the controlling the output to the primary side series capacitor C according to the phase difference data is performed1And secondary side series capacitor C2The duty ratio of the PWM pulse signal of (1) is: regulating and outputting the phase difference data to the primary side series capacitor C by using PI (proportional integral) control1And the secondary side is connected with a capacitor C in series2Duty ratio of the PWM pulse signal.
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