Research On Temperature And Magnetic Field Detection Technology Of Dynamic Wireless Charging For Electric Vehicles

Automobile is the most important means of transportation in modern times.Traditional fuel vehicles are not suitable for the current development situation due to problems such as exhaustion of resources and environmental pollution.Electric vehicles came into being.Besides wired charging and static wireless charging,dynamic wireless charging has many incomparable advantages.However,the field is still in infancy,the development of related supporting technologies is lagging behind.Especially the detection of dynamic wireless charging for electric vehicle remains to be studied.When the dynamic wireless charging system of electric vehicle works,the radiation of the magnetic field cannot be ignored.In addition,the primary and secondary resonant capacitors sometimes explode due to excessive temperature.In response to the above problems,it is necessary to detect the magnetic field environment of the vehicle and the temperature of the primary and secondary resonant capacitors.Although existing instruments can be used in this background,the instruments are generally costly,large in size,difficult to install,and cannot be automated.To this end,the paper is divided into two aspects to introduce the design of temperature detection system and magnetic field detection system.The first part is designing a system for resonance capacitor temperature measurement of electric vehicles dynamic wireless charging.The hardware part of the system mainly studies the selection of the sensor finally adopting PT100,the sensor wiring mode,signal conditioning circuit and peripheral circuit of the main controller.The software part mainly compiles the controller peripheral driver,selects the simple and accurate method to calculate the real-time temperature,and realizes the MODBUS communication protocol.The second part is designing a system for magnetic field intensity measurement of electric vehicles dynamic wireless charging.The hardware part of the system mainly studies the sensor selection finally adopting Honeywell anisotropic magnetoresistive sensor.Then,designs the sensor signal conditioning circuit including set/reset,amplification,two-stage filtering and AD conversion,main controller circuit,ZigBee module and display module circuit.The software part compiles the peripheral driver program of the MCU,the communication program and the driver of the display module.Finally fit the linear relationship between the theoretical value of the magnetic induction intensity and the amplitude of the voltage digital quantity through experiments and simulation results,and obtains the magnetic induction according to the function relationship.The overall cooperation of hardware and software finally realizes the low power design of the entire system.After completing the hardware circuit and program debugging of the temperature detection system and the magnetic field detection system,relevant functional tests were performed.Finally,the actual test on the dynamic wireless charging rail of the electric vehicle shows a good completion effect.The temperature detection system realizes the measurement range including the resonance temperature range,the maximum reaches 0°C-100°C,the resolution is 0.1 °C,and the maximum error is less than 4%.The measurement range of the magnetic field detection system theoretically reaches 150μT,which is far exceeding the electric vehicle dynamic wireless charging magnetic field limit(27μT),the resolution is 1μT,the measurement frequency is 20 kHz,and maximum error is less than 22%.