CN103490527A

CN103490527A - Load identifying method and system of voltage type wireless power supply system

Info

Publication number: CN103490527A
Application number: CN201310482061.1A
Authority: CN
Inventors: 王智慧; 孙跃; 唐春森; 戴欣; 苏玉刚; 叶兆虹
Original assignee: Chongqing University
Current assignee: Chongqing University
Priority date: 2013-10-15
Filing date: 2013-10-15
Publication date: 2014-01-01

Abstract

The present invention proposes a load identification method and system for a voltage-type wireless power supply system. The load identification method includes the following steps: building a voltage-type IPT system, and the primary compensation capacitor Cp of the voltage-type IPT system includes a first capacitor and a second capacitor connected in parallel. Two capacitors, the second capacitor is turned on and off by the controller through switch control; the first capacitor is connected to the primary circuit, and the primary circuit enters a resonance state; the current detection device detects the current of the primary circuit to obtain the first effective value; closed switch, so that the first capacitor and the second capacitor are connected in parallel to the primary circuit, and the controller adjusts the operating frequency of the inverter so that the primary circuit enters a resonant state; the current detection device detects the current of the primary circuit to obtain a second effective value; The controller establishes an impedance equation according to the first effective value and the second effective value of the primary circuit current and the corresponding operating frequency, and obtains the equivalent load impedance Z _L . The invention can realize the accurate detection of the load, and make the IPT system enter the optimal power transmission stage.

Description

A load identification method and system for a voltage-type wireless power supply system

技术领域technical field

本发明涉及IPT（Inductive Power Transfer，感应电能传输）系统的负载识别技术，具体涉及一种电压型无线供电系统负载识别方法及系统。The invention relates to a load identification technology of an IPT (Inductive Power Transfer, inductive power transfer) system, in particular to a load identification method and system for a voltage-type wireless power supply system.

背景技术Background technique

IPT技术是基于法拉第电磁感应原理，利用高频交变磁场实现电能在完全电气绝缘的电源系统和可移动负载间无线传输的一种新型安全的供电技术。该技术已在电动汽车、旋转用电设备、生物医疗、家电和移动电子设备等领域得到了广泛的应用。由于IPT系统所带负载的功率性质和等级跨度大（几毫瓦到上千瓦），若不对负载的性质和功率大小进行辨识，IPT系统工作的稳定性和可靠性会大大降低。因此，当IPT系统正常工作之前，应对负载的性质和功率容量进行识别，从而进入相应适合于该负载的功率传输阶段。IPT technology is a new type of safe power supply technology based on Faraday's electromagnetic induction principle, which uses high-frequency alternating magnetic field to realize wireless transmission of electric energy between a completely electrically insulated power system and a movable load. This technology has been widely used in fields such as electric vehicles, rotating electrical equipment, biomedicine, home appliances and mobile electronic devices. Due to the large power nature and level span of the load carried by the IPT system (several milliwatts to thousands of watts), if the nature and power of the load are not identified, the stability and reliability of the IPT system will be greatly reduced. Therefore, before the IPT system works normally, the nature and power capacity of the load should be identified, so as to enter the corresponding power transmission stage suitable for the load.

由于IPT系统通常具有以下几个特点，一是包含较多的储能元件，其阶数一般高于3；二是由于系统中包含非线性开关网络，因此呈现出严重的开关非线性；三是，由于IPT系统的工作频率一般在20-100kHz左右，因此其工作频率较高。对于高阶、非线性和高频的IPT系统，要进行负载参数识别相当困难，目前，传统的识别技术主要利用原边谐振电压和电流之间的相差来进行负载的识别，需检测太多的变量，使控制系统非常复杂，较难实现。Because the IPT system usually has the following characteristics, first, it contains more energy storage elements, and its order is generally higher than 3; second, because the system contains a nonlinear switching network, it presents serious switching nonlinearity; third, , because the operating frequency of the IPT system is generally around 20-100kHz, its operating frequency is relatively high. For high-order, nonlinear and high-frequency IPT systems, it is quite difficult to identify load parameters. At present, the traditional identification technology mainly uses the phase difference between the primary side resonant voltage and current to identify the load. Too many parameters need to be detected. Variables make the control system very complex and difficult to implement.

对于电压型IPT系统，若采用无线通信模块的方式实现负载辨识，由于同时存在功率传输和无线通信的高频磁场，两者相互的干扰，有可能会使能量传输和无线通信的可靠性降低。若采用基于反射阻抗和检测谐振电压和电流相位差的辨识方法，理论上虽然能够精确辨识负载大小，但是实际上，由于要检测电流峰值，电压峰值以及两者的相差，导致硬件电路及其复杂，过多的被检测量容易影响实际负载识别的精确度。For a voltage-type IPT system, if a wireless communication module is used to realize load identification, due to the presence of high-frequency magnetic fields of power transmission and wireless communication at the same time, the mutual interference between the two may reduce the reliability of energy transmission and wireless communication. If the identification method based on reflected impedance and detection of resonant voltage and current phase difference is adopted, although the load size can be accurately identified in theory, in practice, due to the detection of current peak value, voltage peak value and the phase difference between the two, the hardware circuit is extremely complicated. , too much detected quantity will easily affect the accuracy of actual load identification.

发明内容Contents of the invention

为了克服上述现有技术中存在的缺陷，本发明的目的是提供一种电压型无线供电系统负载识别方法及系统，能够准确识别IPT系统的负载。In order to overcome the above defects in the prior art, the object of the present invention is to provide a load identification method and system for a voltage type wireless power supply system, which can accurately identify the load of the IPT system.

为了实现本发明的上述目的，根据本发明的第一个方面，本发明提供了一种电压型无线供电系统负载识别方法，包括如下步骤：In order to achieve the above object of the present invention, according to the first aspect of the present invention, the present invention provides a load identification method for a voltage-type wireless power supply system, including the following steps:

S1：组建电压型IPT系统，所述电压型IPT系统由原边电路和副边电路组成；S1: Build a voltage-type IPT system, the voltage-type IPT system is composed of a primary side circuit and a secondary side circuit;

所述原边电路设置有直流电源、全桥逆变器以及原边谐振电感Lp和原边补偿电容Cp组成的原边谐振回路，所述原边补偿电容Cp包括并联的第一电容C1和第二电容C2，所述第二电容C2由开关S控制实现接通和切断，所述开关S与控制器相连；The primary side circuit is provided with a DC power supply, a full bridge inverter, a primary side resonant circuit composed of a primary side resonant inductance Lp and a primary side compensation capacitor Cp, and the primary side compensation capacitor Cp includes a first capacitor C1 and a first capacitor connected in parallel. Two capacitors C2, the second capacitor C2 is controlled by a switch S to be turned on and off, and the switch S is connected to the controller;

所述副边电路包括副边谐振电感Ls、副边补偿电容Cs以及等效负载阻抗Z_L，所述副边谐振电感Ls、副边补偿电容Cs和等效负载阻抗Z_L三者依次相连组成副边谐振回路；The secondary circuit includes a secondary resonant inductance Ls, a secondary compensation capacitor Cs, and an equivalent load impedance Z _L , and the secondary resonant inductance Ls, secondary compensation capacitor Cs, and an equivalent load impedance Z _L are sequentially connected to form Secondary resonant circuit;

所述原边电路还设置有电流检测装置，该电流检测装置用于检测所述原边谐振电感Lp内的电流；The primary side circuit is also provided with a current detection device, which is used to detect the current in the primary side resonant inductance Lp;

S2：控制器切断开关S，仅让第一电容C1接入原边电路，直流电源对原边电路进行直流供电，使所述原边电路进入谐振状态；S2: the controller cuts off the switch S, and only connects the first capacitor C1 to the primary circuit, and the DC power supplies DC power to the primary circuit, so that the primary circuit enters a resonant state;

S3：电流检测装置检测原边电路的电流并将原边电路电流的第一有效值与第一工作频率传送到所述控制器中；S3: the current detection device detects the current of the primary circuit and transmits the first effective value and the first operating frequency of the current of the primary circuit to the controller;

S4：控制器闭合开关S，使第一电容C1和第二电容C2并联后接入原边电路，直流电源对原边电路进行直流供电，控制器调节逆变器的工作频率使原边电路进入谐振状态；S4: The controller closes the switch S, so that the first capacitor C1 and the second capacitor C2 are connected in parallel to the primary side circuit, the DC power supplies DC power to the primary side circuit, and the controller adjusts the operating frequency of the inverter so that the primary side circuit enters resonance state;

S5：电流检测装置检测原边电路的电流并将原边电路电流的第二有效值与第二工作频率传输到所述控制器中；S5: the current detection device detects the current of the primary circuit and transmits the second effective value and the second operating frequency of the current of the primary circuit to the controller;

S6：控制器根据原边电路电流的第一有效值、第一工作频率、第二有效值以及第二工作频率建立阻抗方程，求取等效负载阻抗Z_L。S6: The controller establishes an impedance equation according to the first effective value of the primary circuit current, the first operating frequency, the second effective value, and the second operating frequency, and obtains the equivalent load impedance Z _L .

本发明通过改变原边补偿电容的大小，使原边工作在两种不同的谐振频率下，通过建立方式反射阻抗方程，实现负载准确识别，使IPT系统处于最佳功率传输阶段。The invention makes the primary side work at two different resonant frequencies by changing the size of the compensation capacitance of the primary side, and establishes the mode reflection impedance equation to realize accurate identification of the load, so that the IPT system is in the optimal power transmission stage.

为了实现本发明的上述目的，根据本发明的第二个方面，本发明提供了一种电压型无线供电系统负载识别系统，包括电压型IPT系统、电流检测装置和控制器；In order to achieve the above object of the present invention, according to the second aspect of the present invention, the present invention provides a load identification system for a voltage-type wireless power supply system, including a voltage-type IPT system, a current detection device and a controller;

所述电压型IPT系统由原边电路和副边电路组成，所述原边电路设置有直流电源、全桥逆变器以及原边谐振电感Lp和原边补偿电容Cp组成的原边谐振回路，所述原边补偿电容Cp包括并联的第一电容C1和第二电容C2，所述第二电容C2由开关S控制实现接通和切断，所述开关S与控制器相连；The voltage type IPT system is composed of a primary side circuit and a secondary side circuit, and the primary side circuit is provided with a DC power supply, a full bridge inverter, a primary side resonant circuit composed of a primary side resonant inductor Lp and a primary side compensation capacitor Cp, The primary side compensation capacitor Cp includes a parallel first capacitor C1 and a second capacitor C2, the second capacitor C2 is controlled by a switch S to be turned on and off, and the switch S is connected to the controller;

所述电流检测装置用于检测原边电路电流的第一有效值、第一工作频率、第二有效值以及第二工作频率，控制器根据原边电路电流的第一有效值、第一工作频率、第二有效值以及第二工作频率建立阻抗方程，求取等效负载阻抗Z_L。The current detection device is used to detect the first effective value of the primary circuit current, the first operating frequency, the second effective value and the second operating frequency, and the controller according to the first effective value of the primary circuit current, the first operating frequency , the second effective value, and the second operating frequency to establish an impedance equation, and obtain the equivalent load impedance Z _L .

本发明的电压型无线供电系统负载识别系统能够实现负载的准确检测，使IPT系统进入最佳功率传输阶段。The load identification system of the voltage-type wireless power supply system of the present invention can realize accurate load detection, and make the IPT system enter the stage of optimal power transmission.

在本发明的一种优选实施方式中，控制器根据第一有效值、第一工作频率、第二有效值以及第二工作频率建立的阻抗方程为：In a preferred embodiment of the present invention, the impedance equation established by the controller according to the first effective value, the first operating frequency, the second effective value and the second operating frequency is:

$Im Im {Z Z}_{L L} = = \frac{Im Im {Zr Zr}_{11} \cdot &Center Dot; (({u u}_{P P} - - {I I}_{P P 22} {R R}_{P P})) \cdot \cdot {I I}_{P P 11} \cdot \cdot (({ω ω}_{22} {L L}_{S S} - - 11 / / {ω ω}_{22} {C C}_{S S})) - - Im Im {Zr Zr}_{22} \cdot \cdot (({u u}_{P P} - - {I I}_{P P 11} {R R}_{P P})) \cdot &Center Dot; {I I}_{P P 22} \cdot \cdot (({ω ω}_{11} {L L}_{S S} - - 11 / / {ω ω}_{11} {C C}_{S S}))}{Im Im {Zr Zr}_{22} \cdot \cdot (({u u}_{P P} - - {I I}_{P P 11} {R R}_{P P})) \cdot \cdot {I I}_{P P 22} - - Im Im {Zr Zr}_{11} \cdot \cdot (({u u}_{P P} - - {I I}_{P P 22} {R R}_{P P})) \cdot \cdot {I I}_{P P 11}}$

$Re Re {Z Z}_{L L} = = \frac{(({u u}_{P P} - - {I I}_{P P 22} {R R}_{P P})) \cdot &Center Dot; ((11 / / {ω ω}_{22} {C C}_{S S} - - {ω ω}_{22} {L L}_{S S} - - Im Im {Z Z}_{L L}))}{Im Im {Zr Zr}_{22} \cdot &Center Dot; {I I}_{P P 22}}$

ImZ_r1+ω₁L_P-1/ω₁C₁＝0ImZ _r1 +ω ₁ L _P -1/ω ₁ C ₁ =0

$Im Im {Z Z}_{r r 22} + + {ω ω}_{22} {L L}_{P P} - - \frac{11}{{ω ω}_{22} (({C C}_{11} + + {C C}_{22}))} = = 00$

其中，Rp为原边线圈内阻与电容内阻之和，Rs为副边线圈内阻，u_P为逆变桥输出的电压，I_P1为与原边电流的第一有效值，I_P2为原边电流的第二有效值，ω₁为第一工作频率、ω₂为第二工作频率。本发明通过建立阻抗方程，能够对负载进行准确识别。Among them, Rp is the sum of the internal resistance of the primary coil and the internal resistance of the capacitor, Rs is the internal resistance of the secondary coil, u _P is the output voltage of the inverter bridge, I _P1 is the first effective value of the primary current, and I _P2 is The second effective value of the primary current, ω ₁ is the first operating frequency, and ω ₂ is the second operating frequency. The invention can accurately identify the load by establishing an impedance equation.

在本发明的另一种优选实施方式中，所述电流检测装置设置有电流互感器，该电流互感器用于获取原边电路谐振状态的电流波形，在电流互感器的输出端分别连接有谐振电流频率检测单元、谐振电流有效值值采样单元以及谐振电流过零采样单元。In another preferred embodiment of the present invention, the current detection device is provided with a current transformer, which is used to obtain the current waveform in the resonance state of the primary side circuit, and the output terminals of the current transformer are respectively connected to the resonance current A frequency detection unit, a resonant current effective value sampling unit and a resonant current zero-crossing sampling unit.

所述控制器包括频率调节单元和负载识别单元，所述频率调节单元根据所述谐振电流过零采样单元采集的电流过零信号调节全桥逆变器输出的电压的频率使原边电路进入谐振状态，所述负载识别单元分别与所述谐振电流频率检测单元和所述谐振电流有效值采样单元相连，用于建立阻抗方程，对负载进行识别并输出。The controller includes a frequency adjustment unit and a load identification unit, the frequency adjustment unit adjusts the frequency of the voltage output by the full-bridge inverter according to the current zero-crossing signal collected by the resonant current zero-crossing sampling unit to make the primary side circuit enter resonance state, the load identification unit is respectively connected to the resonant current frequency detection unit and the resonant current effective value sampling unit, and is used to establish an impedance equation, identify and output the load.

本发明的显著效果是：方法步骤简单，电路结构容易实现，实施过程中仅需检测不同谐振电容接入情况下原边电流的有效值和工作频率，即可自动判断出负载的接入状况，检测精度高，误差小，有效实现无线电能传输系统的负载识别。The remarkable effect of the present invention is: the method steps are simple, the circuit structure is easy to implement, and in the implementation process, only the effective value and the working frequency of the primary current under the connection of different resonant capacitors need to be detected, and the connection status of the load can be automatically judged. The detection accuracy is high, the error is small, and the load identification of the wireless power transmission system is effectively realized.

附图说明Description of drawings

本发明的上述和/或附加的方面和优点从结合下面附图对实施例的描述中将变得明显和容易理解，其中：The above and/or additional aspects and advantages of the present invention will become apparent and comprehensible from the description of the embodiments in conjunction with the following drawings, wherein:

图1是本发明一种优选实时方式中SS电压型IPT系统电路原理图；Fig. 1 is a schematic circuit diagram of the SS voltage type IPT system in a preferred real-time mode of the present invention;

图2是本发明一种优选实施方式中电流检测装置和控制器的结构图；Fig. 2 is a structural diagram of a current detection device and a controller in a preferred embodiment of the present invention;

图3是本发明电压型无线供电系统负载识别方法的流程图。Fig. 3 is a flow chart of the load identification method of the voltage type wireless power supply system of the present invention.

具体实施方式Detailed ways

下面详细描述本发明的实施例，所述实施例的示例在附图中示出，其中自始至终相同或类似的标号表示相同或类似的元件或具有相同或类似功能的元件。下面通过参考附图描述的实施例是示例性的，仅用于解释本发明，而不能理解为对本发明的限制。Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals designate the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary only for explaining the present invention and should not be construed as limiting the present invention.

在本发明的描述中，除非另有规定和限定，需要说明的是，术语“安装”、“相连”、“连接”应做广义理解，例如，可以是机械连接或电连接，也可以是两个元件内部的连通，可以是直接相连，也可以通过中间媒介间接相连，对于本领域的普通技术人员而言，可以根据具体情况理解上述术语的具体含义。In the description of the present invention, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be mechanical connection or electrical connection, or two The internal communication of each element may be directly connected or indirectly connected through an intermediary. Those skilled in the art can understand the specific meanings of the above terms according to specific situations.

本发明提供了一种电压型无线供电系统负载识别系统，如图1所示，其包括电压型IPT系统和控制器，其中，电压型IPT系统由原边电路和副边电路组成。原边电路设置有全桥逆变器，全桥逆变器的电源端连接直流电源E_DC，全桥逆变器的输出端与原边谐振电感Lp、原边补偿电容Cp相连组成一个串联谐振回路，从图1中可见，原边补偿电容Cp包括并联的第一电容C1和第二电容C2，第二电容C2由开关S控制实现接通和切断，开关S与控制器相连，由控制器控制开关S的通断。原边电路还设置有电流检测装置，电流检测装置与原边谐振电感Lp串联，电流检测装置还与控制器相连，电流检测装置用于检测原边谐振电感Lp内的电流并生成该电流的有效值信息和谐振频率信息。副边电路由副边谐振电感Ls、副边补偿电容Cs、等效负载阻抗Z_L组成，副边谐振电感Ls、副边补偿电容Cs和等效负载阻抗Z_L三者依次相连组成一个串联谐振回路。The present invention provides a load identification system for a voltage-type wireless power supply system, as shown in FIG. 1 , which includes a voltage-type IPT system and a controller, wherein the voltage-type IPT system is composed of a primary side circuit and a secondary side circuit. The primary side circuit is equipped with a full-bridge inverter, the power supply end of the full-bridge inverter is connected to the DC power supply E _DC , and the output end of the full-bridge inverter is connected with the primary side resonant inductor Lp and the primary side compensation capacitor Cp to form a series resonance As can be seen from Figure 1, the primary side compensation capacitor Cp includes a parallel first capacitor C1 and a second capacitor C2, the second capacitor C2 is controlled by a switch S to switch on and off, the switch S is connected to the controller, and the controller Control the on-off of switch S. The primary side circuit is also provided with a current detection device, which is connected in series with the primary side resonant inductance Lp, and the current detection device is also connected to the controller, and the current detection device is used to detect the current in the primary side resonant inductance Lp and generate an effective current of the current. value information and resonant frequency information. The secondary circuit is composed of the secondary resonant inductor Ls, the secondary compensation capacitor Cs, and the equivalent load impedance Z _L. The secondary resonant inductor Ls, the secondary compensation capacitor Cs, and the equivalent load impedance Z _L are sequentially connected to form a series resonance circuit.

如图1所示，开关S1-S4组成一个工作于软开关模式下的全桥逆变器，直流输入E_DC通过逆变器后转变为高频交流电u_p并通过能量发射端谐振网络产生高频交变磁场，副边谐振电感Ls从高频交变磁场中拾取能量，图中u_P为逆变后输出的方波电压，i_P和i_s分别为原边、副边回路电流，M为线圈间的互感，Rp为原边线圈内阻以及电容内阻，Rs为副边线圈内阻。As shown in Figure 1, the switches S1-S4 form a full-bridge inverter working in soft switching mode. The DC input E _DC is converted into high-frequency AC _up after passing through the inverter, and generates high voltage through the resonant network at the energy transmitter. frequency alternating magnetic field, the secondary resonant inductance Ls picks up energy from the high frequency alternating magnetic field, u _P in the figure is the square wave voltage output after inversion, i _P and i _s are the primary and secondary circuit currents respectively, M is the mutual inductance between the coils, Rp is the internal resistance of the primary coil and the internal resistance of the capacitor, and Rs is the internal resistance of the secondary coil.

如图2所示，在本实施方式中，电流检测装置包括谐振电流频率检测单元、谐振电流有效值采样单元和谐振电流过零采样单元，谐振电流频率检测单元用于检测原边电流的谐振频率，谐振电流有效值采样单元和谐振电流过零采样单元分别对原边电路的电流进行有效值采样和电流过零采样。控制器的输入端与电流检测装置的输出端相连，控制器包括频率调节单元和负载识别单元，谐振电流过零采样单元的输出端与频率调节单元的输入端相连，频率调节单元的输出端与全桥逆变器的四个开关分别相连（图1中没有示出），频率调节单元根据谐振电流过零采样单元采集的电流过零信号调节全桥逆变器输出的电压的频率使原边电路进入谐振状态，具体是使原边全桥逆变器输出的电压与原边电流同相位，负载识别单元分别与谐振电流频率检测单元和谐振电流有效值采样单元相连，用于建立阻抗方程，对负载进行识别并输出。As shown in Figure 2, in this embodiment, the current detection device includes a resonant current frequency detection unit, a resonant current effective value sampling unit and a resonant current zero-crossing sampling unit, and the resonant current frequency detection unit is used to detect the resonant frequency of the primary current , the resonant current effective value sampling unit and the resonant current zero-crossing sampling unit respectively perform effective value sampling and current zero-crossing sampling on the current of the primary side circuit. The input end of the controller is connected to the output end of the current detection device, the controller includes a frequency adjustment unit and a load identification unit, the output end of the resonant current zero-crossing sampling unit is connected to the input end of the frequency adjustment unit, and the output end of the frequency adjustment unit is connected to the The four switches of the full-bridge inverter are connected respectively (not shown in Figure 1), and the frequency adjustment unit adjusts the frequency of the voltage output by the full-bridge inverter according to the current zero-crossing signal collected by the resonant current zero-crossing sampling unit so that the primary side The circuit enters the resonant state. Specifically, the voltage output by the full-bridge inverter on the primary side is in the same phase as the current on the primary side. The load identification unit is connected to the resonant current frequency detection unit and the resonant current effective value sampling unit respectively to establish the impedance equation. Identify and output the load.

在本发明的另一种优选实施方式中，原边电路上还可以安装有电流互感器，电流互感器用于获取原边电路谐振状态的电流波形，电流互感器的输出端与谐振电流频率检测单元、谐振电流有效值值采样单元和谐振电流过零采样单元的输入端相连。安全可靠地实现原边电路电流的检测。In another preferred embodiment of the present invention, a current transformer can also be installed on the primary side circuit, and the current transformer is used to obtain the current waveform of the resonance state of the primary side circuit, and the output terminal of the current transformer and the resonance current frequency detection unit The resonant current effective value sampling unit is connected to the input end of the resonant current zero-crossing sampling unit. The detection of the primary side circuit current is realized safely and reliably.

在本实施方式中，原边串联的原边谐振电感Lp、原边补偿电容Cp相当于一个滤波器，对高频谐波电压呈现较大的阻抗，减小了逆变器输出方波电压的高频谐波电流。处于谐振频率的基波信号可以将能量传输到次级回路。在本实施方式中，系统工作在软开关模式下，电压源逆变电路输出方波电压的有效值u_P可近似为：In this embodiment, the primary side resonant inductor Lp and primary side compensation capacitor Cp connected in series with the primary side are equivalent to a filter, which presents a large impedance to the high-frequency harmonic voltage and reduces the output of the square wave voltage of the inverter. High frequency harmonic current. The fundamental signal at the resonant frequency can transfer energy to the secondary loop. In this embodiment, the system works in the soft switching mode, and the effective value u _P of the square wave voltage output by the voltage source inverter circuit can be approximated as:

${u u}_{P P} = = \frac{{44 E E.}_{DC DC}}{\sqrt{22} π π} - - - - - - ((11))$

本发明还提供了一种电压型无线供电系统负载识别方法，如图3所示，包括如下步骤：The present invention also provides a load identification method for a voltage-type wireless power supply system, as shown in Figure 3, comprising the following steps:

S1：组建电压型IPT系统；S1: Build a voltage type IPT system;

本发明中耦合电路工作在原边部分谐振状态，其中原边部分谐振是指对当前系统工作频率，原、副边回路各自电抗都不等于零，而副边回路向原边回路的反射电抗与初级回路自电抗之和等于零。通过切换能量发射端补偿电容的方式改变电路的原边部分谐振频率，在本实施方式中，可控开关S由两个IGBT反向串联而成，接收控制器的控制信号来触发其开通关断。由IGBT构成的可控开关不仅容易控制，并且可使电路在开关S上的压降小、功率损耗小。In the present invention, the coupling circuit works in the partial resonance state of the primary side, wherein the partial resonance of the primary side refers to the current system operating frequency, the respective reactances of the primary and secondary loops are not equal to zero, and the reflected reactance of the secondary loop to the primary loop and the primary loop self The sum of the reactances is equal to zero. The resonant frequency of the primary part of the circuit is changed by switching the compensation capacitor at the energy transmitting end. In this embodiment, the controllable switch S is composed of two IGBTs in reverse series, and receives the control signal of the controller to trigger its on-off . The controllable switch composed of IGBT is not only easy to control, but also can make the voltage drop of the circuit on the switch S small and the power loss small.

当控制器切断开关S，第一电容C1接入系统，系统工作在全谐振状态，系统工作频率为副边固有频率ω₀，满足关系式：When the controller cuts off the switch S, the first capacitor C1 is connected to the system, the system works in a full resonance state, and the system operating frequency is the natural frequency ω ₀ of the secondary side, which satisfies the relationship:

$\frac{11}{{ω ω}_{00}^{22}} = = {L L}_{P P} {C C}_{11} = = {L L}_{S S} {C C}_{S S} - - - - - - ((22))$

在有负载投入系统时，控制器闭合开关S，第一电容C1和第二电容C2并入系统，系统原边失谐，控制器通过检测电流过零点调节逆变器工作频率使得系统工作在原边部分谐振的情况下，由于稳态时电路原边始终工作在谐振状态，逆变输出方波电压与回路电流同向，电流波形为正弦波，故皆可用有效值参与计算。When a load is put into the system, the controller closes the switch S, the first capacitor C1 and the second capacitor C2 are integrated into the system, and the primary side of the system is detuned. The controller adjusts the inverter operating frequency by detecting the current zero crossing point so that the system works on the primary side In the case of partial resonance, since the primary side of the circuit always works in the resonance state in the steady state, the square wave voltage output by the inverter is in the same direction as the loop current, and the current waveform is a sine wave, so the effective value can be used to participate in the calculation.

在ICPT系统中，Zr为副边能量拾取端等效阻抗Zs在原边发射端的反射阻抗，能够反映副边回路对原边回路的影响，可由式（3）（4）计算得到In the ICPT system, Zr is the reflection impedance of the equivalent impedance Zs of the energy pick-up end of the secondary side at the transmitter end of the primary side, which can reflect the influence of the secondary side loop on the primary side loop, which can be calculated by formula (3) (4)

Z_S＝jωL_S+1/jωC_S+jImZ_L+ReZ_L+R_S （3）Z _S ＝jωL _S +1/jωC _S +jImZ _L +ReZ _L +R _S (3)

Z_r＝ω²M²/Z_S＝ReZ_r+jImZ_r （4）Z _r ＝ω ² M ² /Z _S ＝ReZ _r +jImZ _r (4)

计算出反射阻抗的实部虚部分别为：The real and imaginary parts of the calculated reflection impedance are:

$Re Re {Z Z}_{r r} = = \frac{{ω ω}^{22} {M m}^{22} (({R R}_{S S} + + Re Re {Z Z}_{L L}))}{{(({R R}_{S S} + + Re Re {Z Z}_{L L}))}^{22} + + ((11 / / ω ω {C C}_{s the s} - - ω ω {L L}_{S S} - - Im Im {Z Z}_{L L}))} - - - - - - ((55))$

$Im Im {Z Z}_{r r} = = \frac{{ω ω}^{22} {M m}^{22} ((11 / / ω ω {C C}_{S S} - - ω ω {L L}_{S S} - - Im Im {Z Z}_{L L}))}{{(({R R}_{S S} + + Re Re {Z Z}_{L L}))}^{22} + + ((11 - - ω ω {C C}_{s the s} - - ω ω {L L}_{S S} - - Im Im {Z Z}_{L L}))} - - - - - - ((66))$

反射阻抗的实部所消耗的能量为从初级传送到次级回路的能量，虚部用于无功能量交换，参与原边回路谐振。The energy consumed by the real part of the reflected impedance is the energy transmitted from the primary to the secondary circuit, and the imaginary part is used for reactive energy exchange and participates in the resonance of the primary circuit.

原边能量发射端总阻抗Zp为：The total impedance Zp of the energy transmitting end of the primary side is:

Z_P＝jωL_P+1/jωC_P+jImZ_r+ReZ_r+R_P （7）Z _P ＝jωL _P +1/jωC _P +jImZ _r +ReZ _r +R _P (7)

电容C1切入电路时，系统稳态时，原边谐振频率为w1，此时系统反射阻抗为：When the capacitor C1 is cut into the circuit, when the system is in a steady state, the resonance frequency of the primary side is w1, and the reflection impedance of the system at this time is:

${Z Z}_{r r 11} = = {ω ω}_{11}^{22} {M m}^{22} / / {Z Z}_{S S} - - - - - - ((88))$

原边能量发射端回路电流Ip1为：The loop current Ip1 of the energy transmitting end of the primary side is:

${I I}_{P P 11} = = \frac{{u u}_{p p}}{Re Re {Z Z}_{r r 11} + + {R R}_{P P}} - - - - - - ((99))$

若负载为纯阻性负载，此时系统工作在原副边全谐振状态，系统工作频率为系统固有频率。若为阻感性负载，此时初级回路部分谐振频率会偏离固有谐振频率较远，通过在第一电容C1为补偿电容时系统初级回路工作频率偏离固有谐振频率的程度可以很明显地区分负载的性质。If the load is a pure resistive load, the system works in the full resonance state of the primary and secondary sides at this time, and the system operating frequency is the natural frequency of the system. If it is a resistive inductive load, the resonant frequency of the primary circuit part will deviate far from the natural resonant frequency at this time, and the nature of the load can be clearly distinguished by the degree to which the primary circuit operating frequency of the system deviates from the natural resonant frequency when the first capacitor C1 is a compensation capacitor .

之后开关S导通，第二电容C2并入电路，控制器通过调节逆变器的输出电压频率自动调节使系统原边部分谐振，系统稳态时，原边谐振频率为w₂，此时系统反射阻抗为：Afterwards, the switch S is turned on, and the second capacitor C2 is incorporated into the circuit. The controller automatically adjusts the primary side of the system to resonate by adjusting the output voltage frequency of the inverter. When the system is in a steady state, the primary side resonant frequency is w ₂ . The reflected impedance is:

${Z Z}_{r r 22} = = {ω ω}_{22}^{22} {M m}^{22} / / {Z Z}_{S S} - - - - - - ((1010))$

原边能量发射端回路电流IP2为：The loop current IP2 of the primary side energy transmitter is:

${I I}_{P P 22} = = \frac{{u u}_{p p}}{Re Re {Z Z}_{} r r 22 + + {R R}_{P P}} - - - - - - ((1111))$

当通过软开关保证系统原边能量发射端完全谐振时，能量发射端回路虚部为零，即：When the soft switch is used to ensure the complete resonance of the energy transmitter on the primary side of the system, the imaginary part of the energy transmitter circuit is zero, that is:

ImZ_r1+ω₁L_P-1/ω₁C₁＝0 （¹²）ImZ _r1 +ω ₁ L _P -1/ω ₁ C ₁ =0 ( ¹² )

$Im Im {Z Z}_{} r r 22 + + {ω ω}_{22} {L L}_{P P} - - \frac{11}{{ω ω}_{22} (({C C}_{11} + + {C C}_{22}))} = = 00 - - - - - - ((1313))$

联立以上各式得负载的数值：Combine the above formulas to get the load value:

$Im Im {Z Z}_{L L} = = \frac{Im Im {Zr Zr}_{11} \cdot \cdot (({u u}_{P P} - - {I I}_{P P 22} {R R}_{P P})) \cdot &Center Dot; {I I}_{P P 11} \cdot &Center Dot; (({ω ω}_{22} {L L}_{S S} - - 11 / / {ω ω}_{22} {C C}_{S S})) - - Im Im {Zr Zr}_{22} \cdot &Center Dot; (({u u}_{P P} - - {I I}_{P P 11} {R R}_{P P})) \cdot \cdot {I I}_{P P 22} \cdot &Center Dot; (({ω ω}_{11} {L L}_{S S} - - 11 / / {ω ω}_{11} {C C}_{S S}))}{Im Im {Zr Zr}_{22} \cdot &Center Dot; (({u u}_{P P} - - {I I}_{P P 11} {R R}_{P P})) \cdot &Center Dot; {I I}_{P P 22} - - Im Im {Zr Zr}_{11} \cdot \cdot (({u u}_{P P} - - {I I}_{P P 22} {R R}_{P P})) \cdot \cdot {I I}_{P P 11}} - - - - - - ((1414))$

$Re Re {Z Z}_{L L} = = \frac{(({u u}_{P P} - - {I I}_{P P 22} {R R}_{P P})) \cdot \cdot ((11 / / {ω ω}_{22} {C C}_{S S} - - {ω ω}_{22} {L L}_{S S} - - Im Im {Z Z}_{L L}))}{Im Im {Zr Zr}_{22} \cdot \cdot {I I}_{P P 22}} - - - - - - ((1515))$

在本实施方式中，在控制器中还具有互感识别模块，该互感识别模块分别与负载识别单元、谐振电流频率检测单元和谐振电流有效值采样单元相连，用于识别互感的大小，具体计算公式为：In this embodiment, the controller also has a mutual induction identification module, which is connected to the load identification unit, the resonant current frequency detection unit and the resonant current effective value sampling unit respectively to identify the size of the mutual inductance, the specific calculation formula for:

$M m = = \sqrt{\frac{Im Im {Zr Zr}_{22} \cdot \cdot [[Re Re {Z Z}_{} {S S}^{22} + + ((11 / / {ω ω}_{22} {C C}_{S S} - - {ω ω}_{22} {L L}_{S S} - - Im Im {Z Z}_{L L}))]]}{{ω ω}_{22}^{22} \cdot \cdot ((11 / / {ω ω}_{22} {C C}_{S S} - - {ω ω}_{22} {L L}_{S S} - - Im Im {Z Z}_{L L}))}} - - - - - - ((1616))$

在本实施方式中，为了减少系统在电容切换时初级回路失谐过程中逆变器开关管损耗增大的问题，可以在切换电容之前，通过控制器使得逆变器开关管S2、S3关断，S1、S4导通，待到原边谐振电路中能量耗散完之后进行电容的切换，之后控制器使开关管导通并使逆变器恢复正常工作状态。In this embodiment, in order to reduce the problem of increased inverter switch tube loss during the detuning process of the primary circuit during capacitor switching, the inverter switch tubes S2 and S3 can be turned off by the controller before switching capacitors , S1 and S4 are turned on, and the capacitor is switched after the energy is dissipated in the primary side resonant circuit, and then the controller turns on the switch tube and restores the inverter to the normal working state.

在本发明的一种优选实施例中，将负载检测值以及互感的检测值与与电路中实际负载值做比较分析。电路中的具体参数表1所示。In a preferred embodiment of the present invention, the load detection value and the mutual inductance detection value are compared with the actual load value in the circuit for analysis. The specific parameters in the circuit are shown in Table 1.

表1.系统设定参数Table 1. System setting parameters

参数名称parameter name 参数值parameter value 参数名称parameter name 参数值parameter value 输入电压EdcInput voltage Edc 100V100V 补偿电容CsCompensation capacitance Cs 21.1nF21.1nF 补偿电容C1Compensation capacitor C1 14.785nF14.785nF 谐振电感LsResonant inductance Ls 481uH481uH 补偿电容C2Compensation capacitor C2 1.215nF1.215nF 发射回路线阻RsTransmit loop resistance Rs 0.5Ω0.5Ω 谐振电感LpResonant inductance Lp 685.31uH685.31uH 拾取回路线阻RpPickup loop resistance Rp 0.3Ω0.3Ω

表2和表3所示分别为阻性负载和阻感性负载情况下的系统参数识别结果。Table 2 and Table 3 show the identification results of system parameters in the case of resistive load and resistive inductive load respectively.

表2.阻性负载时参数辨识结果Table 2. Parameter identification results for resistive loads

表3.阻感负载时参数辨识结果Table 3. Parameter identification results for resistive loads

从表2和表3可见，本发明能够该识别负载以及互感参数。在阻性负载时识别精度较高，对互感M的识别误差最大为1.6%，对阻性负载的识别误差最大为1%；对互感最大识别误差为1.9%，对阻感负载的实部识别最大误差为4.8%，对感抗的识别误差最大为3.8%。It can be seen from Table 2 and Table 3 that the present invention can identify load and mutual inductance parameters. The recognition accuracy is high in resistive loads, the maximum recognition error for mutual inductance M is 1.6%, the maximum recognition error for resistive loads is 1%; the maximum recognition error for mutual inductance is 1.9%, and the real part recognition for resistive inductive loads The maximum error is 4.8%, and the recognition error for inductive reactance is 3.8%.

在本实施方式中，当识别到的负载虚部小于1μH时，说明这是由于原边全谐振频率值以及电流有效值波动所带来的误差，认为负载为纯阻性。当识别到的负载感性部分大于1μH时，说明实际负载为阻感负载。In this embodiment, when the identified imaginary part of the load is less than 1 μH, it means that this is due to the error caused by the full resonance frequency value of the primary side and the fluctuation of the current RMS value, and the load is considered to be purely resistive. When the recognized inductive part of the load is greater than 1μH, it indicates that the actual load is a resistive inductive load.

本发明通过改变原边补偿电容的大小，使原边工作在两种不同的谐振频率下，通过建立方式反射阻抗方程，实现负载准确识别。The invention makes the primary side work at two different resonant frequencies by changing the size of the compensation capacitance of the primary side, and realizes accurate identification of the load by establishing a mode reflection impedance equation.

需要说明的是，本发明虽然以SS型IPT系统为例进行说明，对于SP型IPT系统，本发明同样适用，这也在本发明的保护范围之内。It should be noted that although the present invention is described by taking the SS type IPT system as an example, the present invention is also applicable to the SP type IPT system, which is also within the protection scope of the present invention.

在本说明书的描述中，参考术语“一个实施例”、“一些实施例”、“示例”、“具体示例”、或“一些示例”等的描述意指结合该实施例或示例描述的具体特征、结构、材料或者特点包含于本发明的至少一个实施例或示例中。在本说明书中，对上述术语的示意性表述不一定指的是相同的实施例或示例。而且，描述的具体特征、结构、材料或者特点可以在任何的一个或多个实施例或示例中以合适的方式结合。In the description of this specification, descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific examples", or "some examples" mean that specific features described in connection with the embodiment or example , structure, material or characteristic is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

尽管已经示出和描述了本发明的实施例，本领域的普通技术人员可以理解：在不脱离本发明的原理和宗旨的情况下可以对这些实施例进行多种变化、修改、替换和变型，本发明的范围由权利要求及其等同物限定。Although the embodiments of the present invention have been shown and described, those skilled in the art can understand that various changes, modifications, substitutions and modifications can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the invention is defined by the claims and their equivalents.

Claims

1. a voltage-type wireless power supply system load recognition methods, is characterized in that: comprise the steps:

S1: set up voltage-type IPT system, described voltage-type IPT system is comprised of former limit circuit and secondary circuit;

Described former limit circuit is provided with the former limit resonant tank of DC power supply, full-bridge inverter and former limit resonant inductance Lp and former limit building-out capacitor Cp composition, described former limit building-out capacitor Cp comprises the first capacitor C 1 and the second capacitor C 2 in parallel, described the second capacitor C 2 is controlled and is realized connecting and cutting off by switch S, and described switch S is connected with controller;

Described secondary circuit comprises secondary resonant inductance Ls, secondary building-out capacitor Cs and equivalent load impedance Z _l, described secondary resonant inductance Ls, secondary building-out capacitor Cs and equivalent load impedance Z _lthe three is connected to form the secondary resonant tank successively;

Described former limit circuit also is provided with current sensing means, and this current sensing means is for detection of the electric current in described former limit resonant inductance Lp;

S2: controller cuts off switch S, only allows the first capacitor C 1 access former limit circuit, and DC power supply is carried out direct current supply to former limit circuit, makes described former limit circuit enter resonance condition;

S3: current sensing means detects the electric current of former limit circuit and the first effective value of former limit circuital current and the first operating frequency is sent in described controller;

S4: controller Closing Switch S, make the first capacitor C 1 and the second capacitor C 2 former limit of rear access in parallel circuit, DC power supply is carried out direct current supply to former limit circuit, and the operating frequency that controller is regulated inverter makes former limit circuit enter resonance condition;

S5: current sensing means detects the electric current of former limit circuit and the second effective value of former limit circuital current and the second operating frequency is transferred in described controller;

S6: controller is set up impedance equation according to the first effective value, the first operating frequency, the second effective value and second operating frequency of former limit circuital current, asks for equivalent load impedance Z _l.

2. voltage-type wireless power supply system load recognition methods according to claim 1 is characterized in that: the impedance equation that described controller is set up according to the first effective value, the first operating frequency, the second effective value and the second operating frequency is:

Im Z_{L} = \frac{Im {Zr}_{1} \cdot (u_{P} - I_{P 2} R_{P}) \cdot I_{P 1} \cdot (ω_{2} L_{S} - 1 / ω_{2} C_{S}) - Im {Zr}_{2} \cdot (u_{P} - I_{P 1} R_{P}) \cdot I_{P 2} \cdot (ω_{1} L_{S} - 1 / ω_{1} C_{S})}{Im {Zr}_{2} \cdot (u_{P} - I_{P 1} R_{P}) \cdot I_{P 2} - Im {Zr}_{1} \cdot (u_{P} - I_{P 2} R_{P}) \cdot I_{P 1}}

Re Z_{L} = \frac{(u_{P} - I_{P 2} R_{P}) \cdot (1 / ω_{2} C_{S} - ω_{2} L_{S} - Im Z_{L})}{Im {Zr}_{2} \cdot I_{P 2}}

ImZ _r1+ω ₁L _P-1/ω ₁C ₁＝0

Im Z_{r 2} + ω_{2} L_{P} - \frac{1}{ω_{2} (C_{1} + C_{2})} = 0

Wherein, Rp is primary coil internal resistance and electric capacity internal resistance sum, and Rs is the secondary coil internal resistance, u _pfor the voltage of inverter bridge output, I _p1for the first effective value with primary current, I _p2for the second effective value of primary current, ω ₁be the first operating frequency, ω ₂it is the second operating frequency.

3. a voltage-type wireless power supply system load recognition system, is characterized in that: comprise voltage-type IPT system, current sensing means and controller;

Described voltage-type IPT system is comprised of former limit circuit and secondary circuit, described former limit circuit is provided with the former limit resonant tank of DC power supply, full-bridge inverter and former limit resonant inductance Lp and former limit building-out capacitor Cp composition, described former limit building-out capacitor Cp comprises the first capacitor C 1 and the second capacitor C 2 in parallel, described the second capacitor C 2 is controlled and is realized connecting and cutting off by switch S, and described switch S is connected with controller;

Described current sensing means is for detection of the first effective value, the first operating frequency, the second effective value and second operating frequency of former limit circuital current, controller is set up impedance equation according to the first effective value, the first operating frequency, the second effective value and second operating frequency of former limit circuital current, asks for equivalent load impedance Z _l.

4. voltage-type wireless power supply system load recognition system according to claim 3, it is characterized in that: described current sensing means is provided with current transformer, this current transformer is for obtaining the current waveform of former limit circuit resonance state, at the output of current transformer, is connected with respectively resonance current frequency detecting unit, resonance current effective value value sampling unit and resonance current zero passage sampling unit.

5. voltage-type wireless power supply system load recognition system according to claim 4, it is characterized in that: described controller comprises frequency adjustment unit and load recognition unit, the frequency that the voltage of full-bridge inverter output is regulated according to the current zero-crossing signal of described resonance current zero passage sampling unit collection in described frequency adjustment unit makes former limit circuit enter resonance condition, described load recognition unit is connected with described resonance current effective value sampling unit with described resonance current frequency detecting unit respectively, for setting up impedance equation, load is identified and exported.