Dielectric barrier discharge reactors are often operated using the pulse density modulation technique. A new resonant converter topology is proposed with energy recovery circuit for efficient PDM mode operation. System description, simulation results and test-stand waveforms are presented and discussed. System topology allows fluent peak-to-peak output voltage control in the resonant mode. Very high efficiency of over 90% is obtained with the means of energy recovery subsystem. High voltage operation is presented with the pulse density modulation (PDM) technique in order to obtain controllable power dissipation into plasma. Exemplary application results regarding marine diesel engine exhaust cleaning are briefly discussed.