The invention relates to a pulse generating system for generating high voltage pulses to energize an electrostatic precipitator (10), the system including: a first power supply (1) and a second power supply (2), where said second power supply (2) is arranged to pre-charge said electrostatic precipitator (10) to a DC voltage; a storage capacitor (7) and a series inductance; a switching device (5) coupled in parallel with an anti-parallel rectifier device (6); and wherein the system is arranged to be coupled to the electrostatic precipitator. The invention relates to provide such a pulse generating system with enhanced efficiency compared to present pulse generating systems and with enhanced protection of the components of the system in case of sparks in the electrostatic precipitator (10). This is achieved, when the switching device (5) of the system has turn-off capability and when the system includes a clamping circuit (11-13; 60-67).