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Chapter 4 Wizards Innovation Series Medium Voltage GP Type - G Drives GEH-6385
Detailed descriptions of the Park and Pulse states are as follows:
Bridge State Description
Off state
All the power devices in the bridge are turned off. Due to the
nature of the power devices and the topology of the power
circuit any currents which exist in off phases are quickly driven
to zero. Phases not included in the pulse or park state remain in
the off state.
Park state The devices in the bridge are turned on in such a way as to
impress no voltage between the selected drive terminals.
Devices are turned on such that the selected drive terminals are
all connected to the same DC voltage potential within the bridge
(MINUS, ZERO or PLUS). Phases not selected for the park
state are left OFF for the duration of the park state. Phases
listed in the park state and NOT listed in the pulse state will
remain in the park state for the duration of the pulse state. Any
current existing in the power bridge will circulate between the
drive and the load and decay to zero at a rate that depends on
the load electrical time constant.
Pulse state
The devices in the bridge are turned on in such a way as to
impress a voltage between the selected drive terminals and the
terminals left in the park state. Voltage is created using the
devices to connect the pulsed terminals to another internal DC
voltage potential. This condition can lead to rising currents if a
load is connected to the bridge. The total phase-phase voltage
developed is the difference between the internal DC bus
voltages selected for the park and pulse states (MINUS, ZERO,
PLUS).
The Pulse Test user specifies the phases to park and the park state potential by
setting parameters Park phase and Park level to desired values.
The Pulse Test user specifies the phases to pulse and the pulse state potential by
setting parameters Pulse phase and Pulse level to desired values.
Consider the following example response for parameters set as follows:
Park phase = A, B, C
Park level = MINUS
Pulse phase =A
Pulse level =PLUS
A
B
C
Plus
Plus
Plus
Minus
Minus
Minus
Zero
Zero
Zero
Task 1
load
pulse
Pulse 1
on time
Mid pulse
off time
Pulse 2
on time
Post
pulse off
time
Task 1
load
pulse