Circuit and method for controlling a high-frequency resonant power conversion system having components with fluctuating parameters

A high-frequency resonant power conversion system for transferring power from an oscillator to a load or vice-versa, the system comprising components with at least one fluctuating parameter and is configured to control a predefined level of a variable selected from:

• a certain current, a certain voltage, a phase difference between a specific voltage and a specific current, and a certain power;
• the system further comprising a virtual impedance creation loop which is configured to create a virtual component, said virtual component forming a basis for changing amplitude and/or phase of the oscillator, thereby to compensate for a deviation of the selected controlled variable from said predefined level due to said at least one fluctuating parameter;
• wherein said virtual impedance creation loop comprising a processor for calculating, based on said predefined level of the selected variable and on circuit measured values, a positive or negative capacitance value, that when added to the system, returns the system to the predefined level of the selected variable;
• and
• wherein said virtual impedance creation loop comprising an integration unit having the form 1/c∫isdt, wherein C is said calculated positive or negative capacitance value, and said is is a sampled current from the system, and a result of an integration performed by said integration unit is a voltage also forming the basis for changing the amplitude and/or phase of the oscillator.