OMD10078 rev F
7
Static Switch: Static Inverter Switch (SSI) and Static Bypass Switch (SB)
Manual Bypass (MB)
1.1
RECTIFIER / BATTERY CHARGER
The Rectifier/Battery charger converts the AC input voltage to DC voltage, feeding
the inverter and keeping the battery charged.
Picture 2 – Rectifier
The AC/DC conversion is carried out by a three-phase three-level PWM rectifier,
combining a three-phase diode bridge with a DC/DC step-up converter. The full-digital
control of the IGBT bridge allows to minimize the harmonics re-injected into the mains
and reduces the harmonic distortion of the current to a very low value even with low
loads. The trend of the power absorbed by the mains is almost sinusoidal with a power
factor higher than 0.99, thanks to the PFC (Power Factor Correction) technology.
The current transducers TA1-TA2-TA3 provide the feedback for the input current
waveform, that is used by the microprocessor to vary the modulation (PWM) of the
IGBT’s.
The battery recharging current is automatically limited by the control software, using
the feedback signals provided by the transducer TA4.