- Honda Car Owner's Manual

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64
MOTORDRIVEMODULE(MDM)
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.
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MDMComponents
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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