V.D.Yudin “High-voltage source with output voltage up to 60 kV with power up to 15 kW

Abstract The presented report contains the description of highvoltage source with output voltage up to 60kV and output current up to 1A. The source consist of the chopper with IGBT switches working with a principle of pulse-width modulation and the fill H-bridge converter with IGBT switches , both working on programmed from 15 to 25 kHz frequency, and the high voltage sectioned transformer with the rectifier and additional capacity filter. The transformer is made in oil tank with silicon oil. The additional capacity filter decreases the ripple and noise level in working range of output currents. The design of the high-voltage transformer provides preservation of working capacity at voltage up to 100kV. A nominal output voltage of the source is 60kV. The source can operate with series of high-voltage breakdowns in output voltage without risk of damage the components of source. In the high-voltage breakdown the released in load and matching circuit energy is less than 15J at maximum operating voltage 65kV. The efficiency of system is more than 80% at the nominally output power 60kW. The controller of the source is developed with DSP and PLM, which allows optimizing operations of the source. For control of the source serial CANinterface is used. The description of the source and the test results are presented. DESCRIPTION The presented source was designed for some different applications at the BINP tasks. That was reason for some specific terms like: short time interval for voltage rise up to 60 kV after high-voltage breakdown, strong reliability to high-voltage breakdown, low voltage ripple for maximal power operation. The energy is dissipated in components of source and in the load during the high voltage breakdown less than 15J for 60 kV operation. The basic characteristics of high-voltage source are shown in Table1. Overview The circuit diagram of power part of high-voltage source is shown in Input rectifier EMI filter is used to eliminate high-frequency noise to the power line from the source. 3-phase rectifier and filter C1-C4 are used to convert input AC 3-phase voltage 380V 50Hz to DC 550-600V voltage. Switch SW1 is used for soft start of converter and its consists two groups of contacts (not shown of sheet). First group of contacts is switched ON and the filter's capacitors C1-C2 are charged with 10A current. When the voltage on filter is up to 450 volts level the second group of contacts is switched ON and the rectifier is connected directly to 3-phase AC line. Chopper The chopper's switches Q1, Q2 are connected in parallel and operates one by one in working circle. As a result, the working frequency of each switch is the half of operated frequency of source. The chopper switches are operated with principle of pulse-width modulation on programmed from 15kHz to 25kHz frequency. The working frequency of inverter is the same. The operating frequency is selected depending on the characteristics of high-voltage transformer and the requirements to the spectrum of output high voltage ripple. The output voltage of chopper is changed from 10 to 450 volts DC by control circuit to obtain the required output high voltage of source. Inverter Full-bridge inverter Q3-Q6 converts DC voltage from chopper's capacitors C3-C4 to AC voltage with programmed from 15 to 25kHz frequency