Jane Medium ： It's tested here ZVS The process of circuit driving charging coil ,  The circuit operation and power output are verified .  This also lays a foundation for the future circuit improvement .

key word ：ZVS, Wireless charging

§01 nothing Wire charging

One 、 Background introduction

   In the national college student smart car competition ,  There is a wireless charging set .  Most power circuits use single transistor , Or half bridge output .  According to the test a few days ago ZVS Basic functions of the circuit ,  Here is a test using ZVS The circuit constitutes the function of the wireless charging circuit .

Two 、 Coil making

   Two wireless transmitting coils are connected in series to form an inductance with an intermediate tap ,  There is mutual inductance between the two coils .  Next, measure the inductance between the three leads .  The inductance between the middle tap and the two ports ,  All in 31uH about .  The inductance of two series coils is 114uH, This also shows that there is a strong mutual inductance between the two .
  

3、 ... and 、 Measurement results

   Connect the above coil ZVS oscillator ,  Preliminary test whether it can produce oscillation .  This is the circuit MOS Tube drain voltage ,  It can be seen that the circuit is oscillating .  No load , The working current of the circuit is 55mA about .

  
   Modify the resonant capacitance to 0.22uF,  here ZVS The oscillation frequency is 32kHz.   Circuit in 12V At operating voltage , The quiescent current is 143mA.  Put one with 10 The ohmic load coil is placed on the coil , It can be seen that the working current increases 0.5A. That is, the output is about 6W Power .  This is the process that the load resistance is burnt out .  Let's see it again .

※ total    junction ※

   this Tested in ZVS The process of circuit driving charging coil ,  The circuit operation and power output are verified .  This also lays a foundation for the future circuit improvement .

One 、 picture DOP

Coil oscillation frequency

According to the circuit $B_1$ and $C_1$ Parameters of , The oscillation frequency of the circuit can be calculated . $$f_0=\frac{1}{2\pi \sqrt{B_1{C}_1}}=\frac{1}{2\pi \sqrt{114\times 10^{-6}\cdot 0.22\times 10^{-6}}}=31.780Hz$$