The power of the device, that is, the output power of the inverter, can be expressed as: Pout = UL2 / Ron (2)
UL-------- voltage on both sides of the sensor
Ron------- equivalent impedance of resonant circuit
It can be seen from the formula that there are two methods to regulate the output power of equipment, namely, voltage regulation and resistance regulation. Since the parallel resonant tank has the highest impedance during resonance, the power factor of the equipment reaches the maximum, which is what we expect. As a result, the voltage regulation is the optimal method, which can not only maintain the equipment at high power factor, but also adjust the output power of the equipment.
U = Ud / cosφ (Ud refers to the DC voltage). We all think that it is good for the cosφ to be adjusted to the maximum, so the power adjustment method by adjustment of the DC voltage is most widely used. The equipment adopts this method. Sometimes, although Ron has been adjusted to the minimum and Ud has been adjusted to the maximum, the required output power still fails to be achieved. In this case, the voltage doubling circuit and the self-coupled boost method can be used (for details, refer to the related books). Besides, shortening the output lead to reduce the line loss is also an effective way to improve the output power.
