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4. Function explanations for each PCB
4.1 PSDR board (POWER STAGE DRIVER)
PSDR board configuration diagram
4.1.1. The power stage (PSDR) consists of DC power supply, power factor correction,
booster, inverter, and output circuits. DC power supply: The input of PSDR is
connected to line input and b/-. So PSDR can provide DC power at line
input and also at battery connected. DC power supply will provide 5V, 12V, ±15V
、
20V HFPW ± DC power for driver circuit.
4.1.2. Power factor correction:
The DSP Controller make the input current and voltage in phase and therefore
achieve a high input power factor.
4.1.3. Booster:
When the input AC power is on, the AC power goes through noise filter to the
pre-charging circuit. The DC capacitors will be pre-charged. When the DC voltage
on DC capacitor achieve the input AC power peak value then input SCR will turn
on. After input SCR turn on, the charger will work and DC capacitors will have 1.4
times of input RMS voltage. Turn on the KEY-ON display from bypass to online, DC
capacitors will have 345VDC.
4.1.4. Inverter sub-system:
The UPS tra/- DC bus voltages to the AC output voltage through an
inverter of half bridge configuration at normal operation.
To construct a high frequency (19.2KHz) PWM inverter, the drivers receive
switching signals from CPU PWM generation circuit through an IGBT Drive Board
to trigger the upper IGBT and the lower IGBT alternately. The output of IGBT is
filtered by a LC circuit to reduce the output voltage harmonic distortion.
