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4.2.1.
Initialization
During the initialization, the power supply control system checks the presence of all internal
components, the embedded PC loads the operating system and the isolation detector runs a
self-test.
No voltage is present at the DC bus and the IGBTs PWMs are completely stopped.
The transition from Initialization state brings the power supply to the Standby state as long as
the emergency stop is deactivated (equipment armed) and the isolation detector performs a
complete self-test successfully.
4.2.2.
Standby
The Standby state keeps the power supply in low power mode until an Enable signal is
received. While the power supply is in standby only the internal power supplies are energized.
In particular, this means that there is no voltage in the DC link and no voltage/current is
applied to the output of the power supply.
The transition from the Standby state is the Enable signal or, in case of errors, a Fault signal.
The Enable signal will bring the State Machine to Precharge and eventually to the Ready state.
If an error is detected the power supply will go into Alarm state.
4.2.3.
Precharge
The Precharge is an internal transition state between Standby and Ready. During this state the
DC link is gradually charged through resistors until the rated DC link voltage is reached. The
transition will finish successfully as long as, in less than 10 seconds of precharge, the DC link
has reached the specified voltage. Otherwise, the next state will be Alarm.
The Precharge state is only applicable to the grid side converter.
4.2.4.
Ready
In the Ready state the power supply is ready to operate but no PWM signal is sent to IGBTs.
The DC bus is charged to the rectified voltage and there is no voltage/current applied to the
outputs.
The transition from Ready state can be the Run signal, the Not enable signal or, in case of
errors, a Fault signal. When a Run signal is received the State Machine will evolve to the Run
state. When a Not enable signal is received the State Machine puts the power supply on
standby, thus discharging the DC link capacitors. If a fault is detected the power supply goes to
Alarm state.
4.2.5.
Run
In this state, the power supply is completely operational. Due to the power supply
architecture, the grid side converter (Active Rectifier) will make the transition first while
