WÄRTSILÄ JOVYREC PME
BAX 5675
- 7 –
6 Operation
6.1 Circuit diagram of switching power supply
6.2 Electrical functional description of switching power
The switching power supply consists of the following main function blocks:
Mains filter for avoiding interspersion of high-frequency disturbances generated by the device into the mains
power supply as well as for damping interfering voltages and voltage transients superimposed on the mains
power supply.
Mains rectifier with synchronized boost converter (operating frequency 70 kHz) for converting the input voltage
into a preregulated direct current of approx. 380V as well as for regulating the wave form of the input current
(sinusiodal) and the power factor (> 0.99, as per EN 61000-3-2). Inrush current limiting is also performed
based on series resistance with bypass relay.
Two transistor half bridges for converting the 380V DC to a pulse width regulated step-shaped AC voltage with
a frequency of 65 kHz.
Two single-ended power converters for electrical isolation and impedance bridging on the second-ary side.
Two rectifier levels with fast-switching power diodes and a common output, thereby frequency doubling to 130
kHz.
LC filter for smoothing the pulsating DC voltage at the rectifier output.
Output filter for avoiding interference voltages at the output voltage.
Auxiliary power supply for internal voltage supply to the primary and secondary controllers with electrical
isolation.
Control process with electrical isolation through trigger transformer.
Control element with parameter setting, signaling, monitoring and display elements. Electrical isolation is
performed by means of optocouplers.
