Motor Drive Module (Mdm); Mdm Components - Honda Insight Owner's Manual

M D M
OTOR RIVE ODULE
The IMA system assists the engine with an electric
motor using power from the Battery Module. It must also
recharge the Battery Module by using power generated
by the motor. It is the Motor Drive Module or MDM
which makes this possible. It can bi-directionally send
current from the motor to the battery and from the
battery to the motor.
During assist mode, power from the Battery Module
is supplied to the IMA Motor in the form of 3-phase
Alternating Current. The current isn't true AC, but
IGBT's (Insulated Gate Bi-polar Transistors) in the
Motor Power Inverter Module (part of the MDM) are
switched in such a way as to simulate AC current.
The Motor Control Module receives constant
feedback from three commutation sensors in the IMA
Motor, and therefore knows the position of the motor. Accurate position information is important because
each phase of the 3-phase current must be switched on at the correct time to ensure proper motor operation.
The Voltage Converter Module (also part of the MDM) receives commands from the Motor Control
Module, and switches the IGBT's appropriately to meet system demands.
During regeneration mode, current flows from the IMA Motor to the MDM. The motor generates true
3-phase Alternating Current, and that AC must be transformed into DC before it can be used to charge the
Battery Module.
Diodes inside the Motor Power Inverter Module are used to rectify the AC power in the same way as
they are used in a typical alternator.
It is very important to note that the IMA Motor is a permanent magnet type and will generate power
whenever it is turning. If the engine were accidentally started with the IPU Compartment opened, the
MDM cables will be hot - even when they are disconnected from the Junction Board. For this reason, the
MDM cable terminals should be wrapped with electrical tape whenever they are disconnected from the
Junction Board.

MDM Components

(MDM)
1. MDM cover
2. Bus bar
3. Electrolytic capacitors
4. Voltage Converter Module
5. Heat sink
6. Capacitor module (supresses voltage
spikes that are generated during high
speed switching at high voltage)
7. Motor Power Inverter (MPI) Module
8. 3 phase current sensors
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