1.POWER STAGE (PSDR)
As shown in figure1, the power stage consists of DC power supply, DC-DC converter, inverter, Input and output circuits.
1-1-1. DC Power Supply Sub-System : (For Pro901S/902S/903S).
The input of the DC power supply is connected to the battery bus, i.e., the output of the charger. The output of DC power supplies provides +12 Vdc for the bias supply of IC's working voltage and the fan(s) voltage. The DC power supply works only when the 12 Vdc regulator supplies Vcc to its control IC. To have proper operation of 12 Vdc regulators, its input power is controlled by the switch as indicated in figure 5.
1-1-2. DC Power Supply Sub-System :(For Pro906S)
The input of the DC power supply is connected to the battery BUS, i.e., the output of the charger. The output of DC power supplies provides 13 Vdc for the bias supply of IC's working voltage and the fan(s) voltage. The DC power supply works only when the 13 Vdc regulator supplies Vcc to its control IC. To have proper operation of 13 Vdc regulators, its input power is controlled by the switch as indicated in figure 5.
1-2 Inverter Sub-System : (For Pro901 & Pro902).
The UPS transfers DC bus voltages to the AC output voltage through an inverter of full bridge configuration in battery mode. The schematic diagram of inverter is shown in figure5. To construct a high frequency (19.2 kHz) PWM inverter, the drivers receive switching signals from PWM generation circuit through 2 PWM ICs to trigger the four IGBT alternately. The output of IGBT is filtered by an LC circuit to reduce the o/p voltage harmonics distortion.
1-3 Inverter Sub-System : (For Pro903)
The UPS converters (＋), (－) DC bus voltages to the AC output voltage through an inverter of half bridge configuration. The schematic diagram of inverter is shown in figure 6.To construct a high frequency (19.2 kHz) PWM inverter, the drivers receive switching signals from PWM generation circuit through a pair of photo-couplers to trigger the upper IGBT and the lowerIGBT alternately. The output of IGBT is filtered by a LC circuit to reduce the o/p voltage harmonics distortion.
Figure 6:
The UPS converters (＋), (－) DC bus voltages to the AC output voltage through an inverter of half bridge configuration. The schematic diagram of inverter is shown in figure 6.To construct a high frequency (19.2 kHz) PWM inverter, the drivers receive switching signals from PWM generation circuit through a pair of photo-couplers to trigger the upper IGBT and the lowerIGBT alternately. The output of IGBT is filtered by a LC circuit to reduce the o/p voltage harmonics distortion.
Figure 6:
1-3 a) The Input Sub-System : (For Pro901/902/903)
All the relays receive signals from control circuit. The Input relay is a safety relay to switch the mains in or not.
All the relays receive signals from control circuit. The Input relay is a safety relay to switch the mains in or not.
1-3-b) The Output Sub-System :
The bypass relay receives signal from control circuit to switch the output. The output relay switches the output of the UPS from bypass to inverter or reverse. The input and output noise filter circuit blocks EMI noise to the loads.
1-4 DC to DC Converter Sub-System :
The major function of the UPS is to deliver accurate AC power to the loads connected to it whenever the AC line is correct or fails. In this system, the batteries release the stored energy to supply inverter immediately upon AC line fails.
Refer to figure 6, the battery voltage is transformed through a push-pull DC-DC converter to 360Vdc as DC buses for inverter. When the line fails, the 360Vdc DC sources are caught up to supply the power needed by the inverter immediately.
The major function of the UPS is to deliver accurate AC power to the loads connected to it whenever the AC line is correct or fails. In this system, the batteries release the stored energy to supply inverter immediately upon AC line fails.
Refer to figure 6, the battery voltage is transformed through a push-pull DC-DC converter to 360Vdc as DC buses for inverter. When the line fails, the 360Vdc DC sources are caught up to supply the power needed by the inverter immediately.
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