Narrowband Frequency Domain Optimized Gate Driving Signals for Power Transistors of DC/DC Converters

Switched transistors of power electronic systems tend to be a source of electromagnetic emissions. Due to steep switching edges, parasitic capacitors and inductances, high frequency oscillations may be triggered by the switching events. These results in narrowband peaks in the frequency domain. A common countermeasure is increasing the gate resistance leading to reduced switching slopes and reduced efficiency of the system. This creates a conflict of interests between the reduction of disturbances and a high system efficiency. More intelligent active gate drivers offer an improvement of this conflict of interests. In this paper, a target signal-oriented gate control is proposed to reduce the disturbances while maintaining steep switching slopes, so the switching losses remain small. The control voltage for the gate is realized by an arbitrary waveform generator with an operational amplifier. A multidimensional Newton's method is used here to determine a suitable gate drive voltage in the frequency domain to reduce the disturbances. The approach is applied to a DC/DC boost converter in simulation and in a laboratory test setup. The benefits of this method regarding to the reduction of electromagnetic interferences and maintaining an acceptable efficiency are discussed.