DSP-based high-frequency HVDC source for verifying internal pressure of vacuum Chamber

Using the HVDC source, whose Voltage is just below the breakdown voltage of the vacuum chamber, we can realize the measuring of the internal pressure within the vacuum interrupters, using only electrical parameters. The HVDC described in this paper is a DSP-based high frequency system. The rectifier and IGBT inverter are controlled by a TMS320LF2407 DSP system, which has the hardware feature of providing a dead-band delay independent of the frequency of operation. This feature, together with the high speed of the DSP, allows the use of zero current resonant switching at a high power factor for frequencies up to 50 kHz. Resonant operation of the inverter is maintained by a simple digital PLL scheme implemented on the DSP. An EMI filter to compensate common mode current using high frequency transistors works just as a power active filter in the harmonic compensation in the power system. Experiment gives out the feasibility of the method on verifying internal pressure in vacuum interrupter.