ABB PQFA, Instruction Manual

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PQFA Instructions Manual
Asea Brown Boveri Jumet S.A.
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The PWM inverter is composed of DC capacitors and an IGBT inverter bridge.
This system is able to generate any voltage waveform with PWM technology.
The physical layout of a PWM inverter module is shown hereafter. Each PWM
inverter is fitted with a local electronic control called the domino board. The
domino board is controlled by the central DSP. The domino board is fitted with
jumpers noted JP100, JP101, JP102, JP103, JP104, JP105, JP106, JP109
and JP110 (JP107 and JP108 are off). In case of several power modules, only
the domino board of the last slave is fitted with jumpers.
The PWM reactors convert the voltage created by the PWM inverter into
currents that will be injected in the network.
The output filter consists in line reactors and an RC shunt circuit.
The function of the preloading circuit is to avoid at start-up high inrush
currents that could damage the power electronics or create transients in the
network.
4.1.2. The control
For best performances, the control of the PQFA is Digital Signal Processor
(DSP) based.
The three lines currents are measured by external CT. Those analogue
signals must first be acquired, levelled and antialias-filtered before
digitalisation. Fast and high precision anlogue-to-digital converters are used to
create a digital representation of the analogue signals. The digitised signals
are then sent to the powerful DSP that controls all measurements and
DC capacitors
Low inductance
DC bus bar
Inverter
Heatsink