EMI mitigation of GaN power inverter leg by local shielding techniques

This paper presents local shielding techniques applied to a half-bridge inverter leg with the aim reduce common mode (CM) current noise at converter's DC input. The research study is conducted for 650V Enhancement Gallium Nitride (GaN) power transistor switches. Main contributors of parasitic capacitances referred inverter-leg middle point node are identified. Then, solutions proposed CM emission by these capacitances. Respecting precautions concerning isolation currents leg, electromagnetic compatibility measurement setup developed. Experimental step-by-step addition copper layers different capacitance shows progressive attenuation spectra.