CN114243945B - 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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- CN114243945B CN114243945B CN202111342014.8A CN202111342014A CN114243945B CN 114243945 B CN114243945 B CN 114243945B CN 202111342014 A CN202111342014 A CN 202111342014A CN 114243945 B CN114243945 B CN 114243945B
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Classifications
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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, a primary side series inductance L f, a primary side series capacitance C 1, a wireless charging primary side coil L 1, a wireless charging secondary side coil L 2, a secondary side series capacitance C 2, a secondary side rectifier bridge, a data acquisition device and a controller, wherein the primary side series capacitance C 1 and the secondary side series capacitance C 2 are switch capacitors. When the relative position of the coil changes, the phase difference value is calculated by detecting the corresponding voltage and current 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 coil self-inductance in the wireless charging system is adapted, 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.
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 connection, so that the charging environment is more attractive and tidy, and the safety problems of circuit aging, poor contact, contact spark and the like are solved. The inductive coupling type wireless power transmission technology realizes wireless transmission of power by utilizing near field coupling of a medium-low frequency electromagnetic field based on an electromagnetic inductive 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 are offset, namely the relative positions are 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.
Disclosure of Invention
In view of the above, it is necessary to provide a wireless charging system and a resonant network matching method thereof that can maintain a resonant state when the relative positions of coils are changed, thereby improving the transmission power and transmission efficiency of the wireless charging system.
The wireless charging system comprises an inverter, a primary side series inductor L f, a primary side series capacitor C 1, a wireless charging primary side coil L 1, a wireless charging secondary side coil L 2, a secondary side series capacitor C 2, a secondary side rectifier bridge, a data acquisition device and a controller, wherein the primary side series capacitor C 1 and the secondary side series capacitor C 2 are switch capacitors; the inverter is connected with a direct-current voltage source and the primary-side series inductor L f, the primary-side series inductor L f is connected with the primary-side series capacitor C 1, the primary-side series capacitor C 1 is connected with the first end of the wireless charging primary-side coil L 1, and the second end of the wireless charging primary-side coil L 1 is connected with the inverter; the first end of the wireless charging secondary side coil L 2 is connected with the secondary side series capacitor C 2, the secondary side series capacitor C 2 is connected with the secondary side rectifier bridge, and the second end of the wireless charging secondary side coil L 2 is connected with the secondary side rectifier bridge; the controller is connected with the data acquisition device, the primary side series capacitor C 1 and the secondary side series capacitor C 2;
The data acquisition device is used for acquiring voltage and current data and sending the voltage and current data to the controller, the controller is used for calculating phase difference data according to the current and voltage data, controlling the duty ratio of PWM pulse signals output to the primary side series capacitor C 1 and the secondary side series capacitor C 2 according to the phase difference data, and adjusting the capacitors of the primary side series capacitor C 1 and the secondary side series capacitor C 2 so that the wireless charging system is resistive and is 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 current between the primary-side series capacitor C 1 and the wireless charging primary-side coil L 1 and sending the current to the controller, and the second voltage sensor is used for detecting the voltage at two ends of the secondary-side series capacitor C 2 and sending the voltage to the controller.
In one embodiment, the switch capacitor includes a capacitor C m1, a capacitor C s1, a capacitor C p1, a switch Q p1, and a switch Q s1, the capacitor C p1 is connected to the first end of the switch Q p1 and then connected in parallel to the capacitor C m1, the switch Q s1 is connected in parallel to the capacitor C s1, and the first end of the switch Q s1 is connected to the second end of the switch Q p1; the control end of the switching tube Q p1 and the control end of the switching tube Q s1 are connected with the controller.
In one embodiment, the switching tube Q p1 and the switching tube Q s1 are both MOS tubes.
In one embodiment, the inverter includes a switching tube T 1, a switching tube T 2, a switching tube T 3, and a switching tube T 4, a first end of the switching tube T 1 is connected to a first end of the switching tube T 3 and then connected to an anode of a dc voltage source, a second end of the switching tube T 1 is connected to a first end of the switching tube T 2 and then connected to the primary-side series inductor L f, a second end of the switching tube T 3 is connected to a first end of the switching tube T 4 and then connected to a second end of the wireless charging primary-side coil L 1, and a second end of the switching tube T 2 is connected to a second end of the switching tube T 4 and then connected to a cathode of the dc voltage source.
In one embodiment, the secondary rectifier bridge includes a diode D 1, a diode D 2, a diode D 3, and a diode D 4, where an anode of the diode D 1 is connected to a cathode of the diode D 2 and then connected to the secondary serial capacitor C 2, an anode of the diode D 3 is connected to a cathode of the diode D 4 and then connected to a second end of the wireless charging secondary coil L 2, a cathode of the diode D 1 and a cathode of the diode D 3 are connected and then used as a first output end of the secondary rectifier bridge, and an anode of the diode D 2 is connected to an anode of the diode D 4 and then used as a second output end of the secondary rectifier bridge.
In one embodiment, the wireless charging system further includes an output capacitor C d, one end of the output capacitor C d is connected to the first output end of the secondary rectifier bridge, and the other end of the output capacitor C d is connected to the second output end of the secondary rectifier bridge.
In one embodiment, the wireless charging system further includes a primary parallel capacitor C f, one end of the primary parallel capacitor C f is connected to a common end of the primary series inductor L f and the primary series capacitor C 1, and the other end of the primary parallel capacitor C f is connected to a second end of the wireless charging primary coil L 1.
A wireless charging system resonance 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 to obtain phase difference data according to the current and voltage data;
And controlling the duty ratio of PWM pulse signals output to the primary side series capacitor C 1 and the secondary side series capacitor C 2 according to the phase difference data, and adjusting the capacitance of the primary side series capacitor C 1 and the secondary side series capacitor C 2 so that the wireless charging system is resistive and is in a resonance state.
In one embodiment, the duty ratio of the PWM pulse signals output to the primary-side series capacitor C 1 and the secondary-side series capacitor C 2 is controlled according to the phase difference data, where: and adjusting the duty ratio of PWM pulse signals output to the primary side series capacitor C 1 and the secondary side series capacitor C 2 by using PI control according to the phase difference data.
According to the wireless charging system and the resonant network matching method thereof, the primary side series capacitor C 1 and the secondary side series capacitor C 2 adopt switch capacitors, phase difference data are obtained through calculation according to voltage and current data acquired by the data acquisition device, the duty ratios of PWM pulse signals output to the primary side series capacitor C 1 and the secondary side series capacitor C 2 are controlled according to the phase difference data, and the capacitors of the primary side series capacitor C 1 and the secondary side series capacitor C 2 are adjusted so that the wireless charging system is in a resistive state and is in a resonant state. When the relative position of the coil changes, the phase difference value is calculated by detecting the corresponding voltage and current 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 coil self-inductance in the wireless charging system is adapted, 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 switch capacitor according to an embodiment;
fig. 3 is an equivalent circuit diagram of an LCC/S type wireless power transmission system according to an embodiment.
Detailed Description
The present application will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present application more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the 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 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. In the following embodiments, "connected" is understood to mean "electrically connected", "communicatively connected", and the like, if the connected circuits, modules, units, and the like have electrical or data transferred therebetween.
As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," and/or the like, specify the presence of stated features, integers, steps, operations, elements, components, or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or groups thereof. Meanwhile, the term used in the present specification includes any and all combinations of the items listed in association.
In one embodiment, as shown in fig. 1, a wireless charging system is provided, including an inverter 100, a primary series inductor L f, a primary series capacitor C 1, a wireless charging primary coil L 1, a wireless charging secondary coil L 2, a secondary series capacitor C 2, a secondary rectifier bridge 200, a data acquisition device and a controller, where the primary series capacitor C 1 and the secondary series capacitor C 2 are switched capacitors. The inverter 100 is connected with a direct-current voltage source V dc and a primary side series inductor L f, the primary side series inductor L f is connected with a primary side series capacitor C 1, the primary side series capacitor C 1 is connected with a first end of a wireless charging primary side coil L 1, and a second end of the wireless charging primary side coil L 1 is connected with the inverter 100; the first end of the wireless charging secondary coil L 2 is connected with a secondary side series capacitor C 2, the secondary side series capacitor C 2 is connected with the secondary side rectifier bridge 200, and the second end of the wireless charging secondary coil L 2 is connected with the secondary side rectifier bridge 200; the controller is connected with the data acquisition device, the primary side series capacitor C 1 and the secondary side series capacitor C 2.
In fig. 1, a resistor R f represents the internal resistance of the primary-side series inductor L f, a resistor R 1 represents the internal resistance of the wireless charging primary-side coil L 1, and a resistor R 2 represents the internal resistance of the wireless charging secondary-side coil L 2. The controller may specifically be a DSP (DIGITAL SIGNAL Processing digital signal) controller. The data acquisition device is used for acquiring voltage and current data and sending the voltage and current data to the controller, the controller is used for calculating phase difference data according to the current and voltage data, and controlling the duty ratio of PWM pulse signals output to the primary side series capacitor C 1 and the secondary side series capacitor C 2 according to the phase difference data, and the capacitors of the primary side series capacitor C 1 and the secondary side series capacitor C 2 are adjusted so that the wireless charging system is resistive and is in a resonance state. The controller outputs pulse signal PWM1 to primary series capacitor C 1, adjusts the capacitance value of primary series capacitor C 1, and outputs pulse signal PWM2 to secondary series capacitor C 2, adjusts the capacitance value of secondary series capacitor C 2.
Specifically, in one embodiment, with continued reference to fig. 1, the data acquisition device includes a first current sensor for detecting an output current I in_ac of the inverter 100 and sending to the controller, a second current sensor for detecting an output voltage U in_ac of the inverter 100 and sending to the controller, a first voltage sensor, and a second voltage sensor; the second current sensor is used for detecting the current I 1 between the primary side series capacitor C 1 and the wireless charging primary side coil L 1 and sending the current I 1 to the controller, and the second voltage sensor is used for detecting the voltage U c2 at two ends of the secondary side series capacitor C 2 and sending the voltage U c2 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 carries out data analysis according to corresponding voltage and current signals in the Hall sensor detection circuit to obtain corresponding phase difference signals, so that PWM pulse signals for controlling a switching tube in a switched capacitor structure can be obtained through PI (Proportional Integral Controller, proportional adjustment and integral adjustment) control to obtain corresponding equivalent capacitors, the whole wireless charging system is made to be resistive, the purpose of enabling the system to be in resonance is achieved, and the maximum output voltage and transmission efficiency of the wireless charging system during coil deflection are guaranteed. The controller can pre-store the corresponding relation between the phase difference and the capacitance value adjusting amplitude, after the actual phase difference is calculated according to the voltage and current signals which are actually collected, the capacitance value adjusting amplitude which needs to be adjusted can be determined according to the stored corresponding relation, and then the duty ratio of the PWM pulse signal is changed through PI control, so that the capacitance values of the two switch capacitors are changed.
The specific structure of the switched capacitor is not unique, in one embodiment, as shown in fig. 2, the switched capacitor includes a capacitor C m1, a capacitor C s1, a capacitor C p1, a switching tube Q p1, and a switching tube Q s1, the capacitor C p1 is connected to the first end of the switching tube Q p1 and then is connected to the capacitor C m1 in parallel, the switching tube Q s1 is connected to the capacitor C s1 in parallel, and the first end of the switching tube Q s1 is connected to the second end of the switching tube Q p1; the control end of the switching tube Q p1 and the control end of the switching tube Q s1 are connected with a controller. The switching tube Q p1 and the switching tube Q s1 are control switching tubes, which may be triode or MOS tubes, and in this embodiment, the switching tube Q p1 and the switching tube Q s1 are MOS tubes.
Specifically, after one end of the capacitor C p1 is connected in series with the source of the switching tube Q p1, the capacitor C m1 is connected in parallel with the whole, the drain of the switching tube Q p1 is connected with the source of the switching tube Q s1, and the switching tube Q s1 is connected in parallel with the capacitor C s1. One end of the capacitor C m1 is connected to one end of the capacitor C s1, and the other end of the capacitor C m1 and the other end of the capacitor C s1 are used for accessing a circuit. The gates of the switching tube Q p1 and the switching tube Q s1 are both connected to a controller, and the controller changes the equivalent capacitance of the switching capacitor by changing the duty ratio of the PWM pulse signals sent to the gate of the switching tube Q p1 and the gate of the switching tube Q s1.
In one embodiment, with continued reference to fig. 1, the inverter 100 includes a switching tube T 1, a switching tube T 2, a switching tube T 3, and a switching tube T 4, a first end of the switching tube T 1 and a first end of the switching tube T 3 are connected to a positive pole of the dc voltage source V dc, a second end of the switching tube T 1 is connected to a first end of the switching tube T 2 and to the primary-side series inductor L f, a second end of the switching tube T 3 and a first end of the switching tube T 4 are connected to a second end of the wireless charging primary-side coil L 1, the second end of the switching tube T 2 is connected with the second end of the switching tube T 4 and then connected with the negative electrode of the direct-current voltage source V dc. In addition, the controller may be further connected to the control ends of the switching tube T 1, the switching tube T 2, the switching tube T 3, and the switching tube T 4, and by controlling the on/off of the switching tube T 1, the switching tube T 2, the switching tube T 3, and the switching tube T 4, the inverter 100 performs the inversion processing on the dc power output by the dc voltage source V dc to obtain ac power. Wherein, the switch tube T 1, the switch tube T 2, the switch tube T 3 and the switch tube T 4 can all adopt MOS tubes.
In one embodiment, the wireless charging system further includes a primary parallel capacitor C f, one end of the primary parallel capacitor C f is connected to a common end of the primary series inductor L f and the primary series capacitor C 1, and the other end of the primary parallel capacitor C f is connected to a second end of the wireless charging primary coil L 1.
In one embodiment, secondary rectifier bridge 200 includes diode D 1, diode D 2, diode D 3, and diode D 4, the anode of diode D 1 is connected to the cathode of diode D 2 and then to secondary series capacitor C 2, the anode of diode D 3 and the cathode of diode D 4 are connected to the second end of wireless charging secondary coil L 2, the cathode of diode D 1 and the cathode of diode D 3 are connected to serve as the first output of secondary rectifier bridge 200, and the anode of diode D 2 is connected to the anode of diode D 4 and then to serve as the second output of secondary rectifier bridge 200. The first output end and the second output end of the secondary rectifying bridge 200 are used for being connected with load equipment, the secondary rectifying bridge 200 rectifies induction alternating current, and outputs direct current to supply power to the load equipment.
In addition, in one embodiment, the wireless charging system further includes an output capacitor C d, one end of the output capacitor C d is connected to the first output end of the secondary rectifier bridge 200, and the other end of the output capacitor C d is connected to the second output end of the secondary rectifier bridge 200. The output capacitor C d can stabilize the direct current output by the secondary side rectifier bridge 200, and improves the power supply stability.
According to the wireless charging system, when the relative position of the coil changes, the phase difference value is calculated by detecting the corresponding voltage and current in the wireless charging system, so that the duty ratio of the PWM pulse signal for controlling the switch capacitor is adjusted, the change of coil self-inductance in the wireless charging system is adapted, 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.
In one embodiment, a method for matching a resonant network of a wireless charging system is further provided, and the method is implemented based on the wireless charging system, and 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; and controlling the duty ratio of PWM pulse signals output to the primary side series capacitor C 1 and the secondary side series capacitor C 2 according to the phase difference data, and adjusting the capacitors of the primary side series capacitor C 1 and the secondary side series capacitor C 2 so that the wireless charging system is resistive and is in a resonance state.
In one embodiment, the duty cycle of the PWM pulse signals output to the primary side series capacitor C 1 and the secondary side series capacitor C 2 is controlled according to the phase difference data, which is: the duty ratio of the PWM pulse signals output to the primary side series capacitor C 1 and the secondary side series capacitor C 2 is adjusted using PI control according to the phase difference data.
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 in the wireless charging system, so that the duty ratio of PWM pulse signals for controlling the switch capacitor is adjusted, the self-inductance change of the coil 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 above wireless charging system and the resonant network matching method thereof, the following detailed explanation is provided with reference to specific embodiments.
The inductive coupling type wireless power transmission technology realizes wireless transmission of power by utilizing near field coupling of a medium-low frequency electromagnetic field based on an electromagnetic inductive 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 primary side constant current and secondary side constant output voltage, and is widely applied to wireless charging systems.
Fig. 3 is a schematic diagram of an equivalent circuit of an LCC/S wireless power transfer system according to the present application. In the wireless charging system, there are three sets of resonance conditions:
When all three sets of resonance conditions are met, the system output power and efficiency reach maximum values. When the primary coil and the secondary coil are offset, that is, the relative positions of the primary coil and the secondary coil are changed, the mutual inductance M and the self inductance L 1 and L 2 of the two coils are changed. When the mutual inductance of the coils changes, the output voltage of the system changes. When self-inductance L 1 and L 2 are changed, the resonance condition is not satisfied, the reactive power component of the system is increased, and the output power and efficiency are reduced.
In order to keep the wireless charging system in a resonant state, the industry mainly starts from the angles of frequency conversion and variable capacitance to adapt to the changes of coil self-inductance L 1 and coil self-inductance L 2 so that the system is in a resonant state at all times. Regarding the frequency conversion method, because of the large number of resonance conditions used in LCC/S topology, the single frequency conversion method cannot satisfy the resonance conditions in the system. Regarding the method of varying the capacitance, it is a viable solution to bring the system again in resonance by changing the capacitance values of the capacitances C 1 and C 2 to accommodate the changes in the coil self-inductance L 1 and L 2.
Currently, there are mainly capacitor matrices and voltage controlled capacitors for devices with variable capacitance. The capacitor matrix is used for changing the capacitance value by switching the weighted binary capacitors connected in parallel, but the capacitance changing mode cannot realize continuous adjustment of the capacitance value and needs a plurality of switches and capacitors. The voltage control capacitor controls the conducting 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 varactor approach is only suitable for low power applications.
Based on the above, the application provides a method for maintaining the wireless charging system in a resonance state when the relative position of the coil changes by using the switch capacitor, so as to further improve the transmission power and the transmission efficiency of the wireless charging system.
As shown in fig. 1, the circuit constituent elements of the wireless charging system include: the direct-current voltage source V dc, an inverter consisting of four switching tubes T 1、T2、T3、T4, a primary side series inductor L f, a primary side parallel capacitor C f, a primary side series capacitor C 1, a wireless charging primary side coil L 1, a wireless charging secondary side coil L 2, a secondary side series capacitor C 2, a secondary side rectifier bridge and a load resistor R. The direct-current voltage source V dc is connected in series with the primary side series inductor L f after passing through the inverter, then is connected in parallel with the primary side parallel capacitor C f, one end of the primary side parallel capacitor C f is connected with one end of the primary side series capacitor C 1, the other end of the primary side series capacitor C 1 is connected with one end of the wireless charging primary side coil L 1, and the other end of the wireless charging primary side coil L 1 is connected with the other end of the primary side parallel capacitor C f. The wireless charging secondary side coil L 2 is connected with the secondary side series capacitor C 2 in series and then is connected with a secondary side rectifier bridge, and a resistor load R is connected to the rear direct current side of the secondary side rectifier bridge. Resistor R f represents the internal resistance of primary side series inductance L f, resistor R 1 represents the internal resistance of wireless charging primary side coil L 1, and resistor R 2 represents the internal resistance of wireless charging secondary side coil L 2.
The primary side series capacitor C 1 and the secondary side series capacitor C 2 adopt a switched capacitor structure to adapt to the change of coil self inductance, so that the matching of a coil resonance network is realized, and the system is in a resonance state at any time.
A switched capacitor structure: the switch tube and the capacitor are switched in series and parallel, and the equivalent capacitor is changed by controlling the ratio of series connection and parallel connection, so that the change of the capacitance value is realized. The capacitor structure can realize a wide range of capacitance values. As shown in fig. 2, the specific circuit connection manner of the switch capacitor is as follows: after one end of the capacitor C p1 is connected in series with the source of the switching tube Q p1, the capacitor C m1 is connected in parallel as a whole, the drain of the switching tube Q p1 is connected with the source of the switching tube Q s1, and the switching tube Q s1 is connected in parallel with the capacitor C s1.
The method for realizing the self-adaptive resonance comprises the following steps:
When the wireless charging system is in a resonance state, the whole circuit can show pure resistance; when the system is not in a resonant state, the circuit may exhibit capacitive or inductive characteristics. Therefore, the application judges whether the system is in a resonance state or not by detecting the phase difference between the voltage signal and the current signal corresponding to the wireless charging system. The capacitance value is controlled by controlling the conduction proportion of a switching tube in the switch capacitor structure, so that the self-inductance change of a coil in a wireless charging system is adapted, and the system is in a resonance state at all times.
The specific implementation steps are as follows:
The corresponding voltage and current signals in the circuit are detected by utilizing the Hall sensor, the signals are processed and sent into the DSP, the signals are subjected to data analysis in the DSP to obtain corresponding phase difference signals, and further, the PI control is used to obtain PWM pulse signals for controlling the switching tube in the switched capacitor structure, so that corresponding equivalent capacitors are obtained, the whole wireless charging system is resistive, the purpose of enabling the system to be in resonance is achieved, and the maximum output voltage and transmission efficiency of the wireless charging system during coil deflection are ensured.
The method for maintaining the wireless charging system in the resonance state when the relative position of the coil changes by using the switched capacitor aims at solving the problems that the system is detuned and the output power and the transmission efficiency of the wireless charging system are reduced due to self-inductance change caused by the relative position change of the coil in the wireless charging system, and the primary side series capacitor C 1 and the secondary side series capacitor C 2 adopt switched capacitors with variable capacitance values instead of capacitors with fixed capacitance values. The phase difference is calculated by detecting corresponding voltage and current signals in the wireless charging system, the PWM signal for controlling the switching tube in the switching capacitor is calculated by utilizing the PI control phase difference to be zero, the two resonance capacitance values are adjusted by adjusting the conduction proportion of the switching tube of the switching capacitor, and the system is in a resonance state at all times by adapting to the change of the capacitance value, so that the aim of improving the output power and the transmission efficiency of the system is fulfilled.
The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims.
Claims (7)
1. The wireless charging system is characterized by comprising an inverter, a primary side series inductor L f, a primary side series capacitor C 1, a wireless charging primary side coil L 1, a wireless charging secondary side coil L 2, a secondary side series capacitor C 2, a secondary side rectifier bridge, a data acquisition device and a controller, wherein the primary side series capacitor C 1 and the secondary side series capacitor C 2 are switch capacitors; the inverter is connected with a direct-current voltage source and the primary-side series inductor L f, the primary-side series inductor L f is connected with the primary-side series capacitor C 1, the primary-side series capacitor C 1 is connected with the first end of the wireless charging primary-side coil L 1, and the second end of the wireless charging primary-side coil L 1 is connected with the inverter; the first end of the wireless charging secondary side coil L 2 is connected with the secondary side series capacitor C 2, the secondary side series capacitor C 2 is connected with the secondary side rectifier bridge, and the second end of the wireless charging secondary side coil L 2 is connected with the secondary side rectifier bridge; the controller is connected with the data acquisition device, the primary side series capacitor C 1 and the secondary side series capacitor C 2;
the data acquisition device is used for acquiring current and voltage data and sending the current and voltage data to the controller, the controller is used for calculating phase difference data according to the current and voltage data, controlling the duty ratio of PWM pulse signals output to the primary side series capacitor C 1 and the secondary side series capacitor C 2 according to the phase difference data, and adjusting the capacitors of the primary side series capacitor C 1 and the secondary side series capacitor C 2, and adapting to self-inductance change through change of capacitance values so that the wireless charging system is in a resistive and resonant state;
The switch capacitor comprises a capacitor C m1, a capacitor C s1, a capacitor C p1, a switch tube Q p1 and a switch tube Q s1, wherein the capacitor C p1 is connected with a first end of the switch tube Q p1 and then connected with the capacitor C m1 in parallel, the switch tube Q s1 is connected with the capacitor C s1 in parallel, and a first end of the switch tube Q s1 is connected with a second end of the switch tube Q p1; the control end of the switching tube Q p1 and the control end of the switching tube Q s1 are connected with the controller; wherein the switching tube Q p1 and the switching tube Q s1 are control switching tubes;
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 current between the primary side series capacitor C 1 and the wireless charging primary side coil L 1 and sending the current to the controller, and the second voltage sensor is used for detecting the voltage at two ends of the secondary side series capacitor C 2 and sending the voltage to the controller;
After one end of the capacitor Cp1 is connected with the source electrode of the switching tube Qp1 in series, the capacitor Cp1 is connected with the capacitor Cm1 in parallel as a whole, the drain electrode of the switching tube Qp1 is connected with the source electrode of the switching tube Qs1, and the switching tube Qs1 is connected with the capacitor Cs1 in parallel;
The secondary side rectifier bridge comprises a diode D1, a diode D2, a diode D3 and a diode D4, wherein an anode of the diode D1 is connected with a cathode of the diode D2 and then connected with the secondary side series capacitor C2, an anode of the diode D3 is connected with a cathode of the diode D4 and then connected with a second end of the wireless charging secondary side coil L2, a cathode of the diode D1 is connected with a cathode of the diode D3 and then used as a first output end of the secondary side rectifier bridge, and an anode of the diode D2 is connected with an anode of the diode D4 and then used as a second output end of the secondary side rectifier bridge.
2. The wireless charging system of claim 1, wherein the switching tube Q p1 and the switching tube Q s1 are both MOS tubes.
3. The wireless charging system of claim 1, wherein the inverter comprises a switching tube T 1, a switching tube T 2, a switching tube T 3 and a switching tube T 4, wherein a first end of the switching tube T 1 and a first end of the switching tube T 3 are connected to an anode of a dc voltage source, a second end of the switching tube T 1 is connected to a first end of the switching tube T 2 and then to the primary-side series inductor L f, a second end of the switching tube T 3 and a first end of the switching tube T 4 are connected to a second end of the wireless charging primary-side coil L 1, and a second end of the switching tube T 2 and a second end of the switching tube T 4 are connected to a cathode of the dc voltage source.
4. The wireless charging system of claim 1, further comprising an output capacitor C d, wherein one end of the output capacitor C d is connected to the first output terminal of the secondary rectifier bridge, and the other end of the output capacitor C d is connected to the second output terminal of the secondary rectifier bridge.
5. The wireless charging system of any of claims 1-4, further comprising a primary parallel capacitor C f, wherein one end of the primary parallel capacitor C f is connected to a common terminal of the primary series inductor L f and the primary series capacitor C 1, and wherein the other end of the primary parallel capacitor C f is connected to a second terminal of the wireless charging primary coil L 1.
6. A wireless charging system resonant network matching method, characterized in that, based on the wireless charging system of any one of claims 1-5, the method comprises:
receiving current and voltage data sent by a data acquisition device, and calculating to obtain phase difference data according to the current and voltage data;
And controlling the duty ratio of PWM pulse signals output to the primary side series capacitor C 1 and the secondary side series capacitor C 2 according to the phase difference data, and adjusting the capacitance of the primary side series capacitor C 1 and the secondary side series capacitor C 2 so that the wireless charging system is resistive and is in a resonance state.
7. The method of claim 6, wherein the duty cycle of the PWM pulse signals output to the primary-side series capacitor C 1 and the secondary-side series capacitor C 2 is controlled according to the phase difference data, and is as follows: and adjusting the duty ratio of PWM pulse signals output to the primary side series capacitor C 1 and the secondary side series capacitor C 2 by using PI control according to the phase difference data.
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| CN109302070A (en) * | 2018-10-09 | 2019-02-01 | 李建科 | Circuit topology structure of power converter and its control method |
| CN109660029A (en) * | 2019-02-18 | 2019-04-19 | 浙江万安亿创电子科技有限公司 | It enjoys a double blessing bridge radio energy transmission system soft switch circuit |
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| CN105634093B (en) * | 2016-04-01 | 2018-01-09 | 杨军 | A kind of more mobile phone movable three-dimensional wireless charging devices |
| CN109245536A (en) * | 2018-08-24 | 2019-01-18 | 李建科 | A kind of circuit topological structure suitable for the transmission of two-way near field electric energy |
| CN109120072B (en) * | 2018-09-04 | 2020-06-02 | 合肥工业大学 | Constant voltage and efficiency optimization control method of S/SP wireless charging system |
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| CN109302070A (en) * | 2018-10-09 | 2019-02-01 | 李建科 | Circuit topology structure of power converter and its control method |
| CN109660029A (en) * | 2019-02-18 | 2019-04-19 | 浙江万安亿创电子科技有限公司 | It enjoys a double blessing bridge radio energy transmission system soft switch circuit |
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