HIGH VOLTAGE CIRCUIT START/CUT OFF CONTROL
id304000200300
Outline
• The PCM connects and cuts off the high voltage circuit by turning the 3 high voltage contactors on and off to assure the safety of the high voltage parts.
• The high voltage contactor control performs the following 8 types of operations depending on the vehicle conditions.
High voltage contactor control types
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Control type
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Operation description
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Power switch linked operation
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• The high voltage circuit is connected/cut off in conjunction with the power switch operation.
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Cut off during collision
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• In the event of a vehicle collision, the PCM assures safety by turning off the high voltage contactor and cutting off the power to the high voltage circuit.
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Interlock switch linked cut off
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• If a worker accidentally removes a high voltage part while the main power is switched ON (READY on) or the high voltage circuit is connected such as when charging, the PCM turns off the high voltage contactors to assure the safety of the worker.
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High voltage battery charging linked operation
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• The high voltage circuit is connected/cut off in conjunction with the high voltage battery charging operation.
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High voltage battery cooling system linked operation
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• The high voltage circuit is connected/cut off in conjunction with the high voltage battery cooling system operation.
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Battery heater system linked operation
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• The high voltage circuit is connected/cut off in conjunction with the battery heater system operation.
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Remote climate control/climate control timer linked operation
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• The high voltage circuit is connected/cut off in conjunction with the remote climate control/climate control timer operation.
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Auxiliary device power charging system linked operation
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• The high voltage circuit is connected/cut off in conjunction with the auxiliary device power charging determination by the PCM.
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Block Diagram
Operation
Power switch linked operation
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• When the main power is switched ON, the PCM turns on/off the high voltage contactors in 6 steps as follows when it receives the EV system start request signal ) from the body control module (BCM).
• If an operation is performed while the charging cable is connected, such as the power switch is operated, the PCM does not accept the operation (ready-to-drive status (READY on) is not attained). As a result, safety during charging is assured.
EV system is started
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Step
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High voltage contactor (+)
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Precharge contactor
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High voltage contactor (-)
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—
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OFF
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OFF
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OFF
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1
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OFF
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ON
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OFF
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2
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ON
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ON
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OFF
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3
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ON
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ON
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ON
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4
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ON
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OFF
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ON
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EV system is stopped
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Step
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High voltage contactor (+)
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Precharge contactor
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High voltage contactor (-)
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5
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ON
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OFF
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OFF
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6
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OFF
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OFF
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OFF
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• The high voltage circuit and high voltage parts are protected from high voltage inrush current by flowing electrical current through the pre-charge resistor first.*
* :When power is turned on, high amount of electrical current flows temporarily
Cut off during collision
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• The PCM turns off the high voltage contactors when it receives an air bag activation (deployment) signal from the SAS control module.
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• The air bag operation (deployment) signal uses two systems, including CAN communication and the signal line, to assure reliability against vehicle damage in the event of a collision.
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Step
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Operation description
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1
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SAS control module detects collision requiring SAS control module to operate air bags
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2
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SAS control module sends air bag operation signal via CAN communication and signal line
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3
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PCM receives air bag operation signal from SAS control module
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4
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PCM turns off power to high voltage contactor (+) and high voltage contactor (-)
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5
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High voltage contactor (+) and high voltage contactor (-) turn off, and high voltage circuit is cut off
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Interlock switch linked cut off
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• If a part with a built-in interlock switch is removed while the high voltage circuit is connected, the interlock switch turns off.
• When the interlock switch turns off, the PCM turns off the high voltage contactors.
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Step
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Operation description
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1
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Circuit opens when any interlock switch is turned off
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2
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PCM detects that interlock switch circuit is open
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3
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PCM turns off power to high voltage contactor (+) and high voltage contactor (-)
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4
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High voltage contactor (+) and high voltage contactor (-) turn off, and high voltage circuit is cut off
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High voltage battery charging linked operation
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• During high voltage battery charging, it is necessary to connect the charging system and the high voltage battery circuit.
• When the charging connector is connected to the vehicle, the charging control unit sends a PCM start request signal to the PCM via CAN communication. (See
HIGH VOLTAGE BATTERY CHARGING CONTROL.)
• When the PCM receives the start request, it turns the high voltage contactors on/off and it connects the high voltage circuit using the same procedure as the power switch linked operation. (See
Power switch linked operation.)
• During quick charging, the PCM also connects the QBC contactor at the same time via the QBC contactor drive relay. As a result, the charging equipment and the high voltage circuit are connected. (See
CHARGING SYSTEM [(E)])
• When the high voltage battery stops charging, the PCM turns off the high voltage contactor and cuts off the high voltage circuit.
High voltage battery cooling system linked operation
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• To cool the high voltage battery regardless of whether or not the main power is switched OFF or ON (READY off or on) when the high voltage battery is hot, it is necessary to supply high voltage battery power for driving the electric compressor. (See
HIGH VOLTAGE BATTERY COOLING CONTROL.)
• When the PCM determines that the high voltage battery cooling system operation is required based on the high voltage battery temperature input from the BECM via CAN communication and the user selects high voltage battery cooling on the center display, it turns the high voltage contactors on/off and connects the high voltage circuit using the same procedure as the power switch linked operation. (See
Power switch linked operation.)
• When the high voltage battery is cooled and the high voltage battery cooling system operation is stopped, the PCM turns off the high voltage contactors and cuts off the high voltage circuit.
Battery heater system linked operation
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• To warm the high voltage battery regardless of whether or not the main power is switched OFF or ON (READY off or on) when the high voltage battery temperature decreases during parking at extremely low temperatures, it is necessary to supply power from the high voltage battery to the battery heater. (See
BATTERY HEATER CONTROL.)
• When the PCM receives the battery heater drive request from the BECM via CAN communication and determines the battery heater operation, it turns the high voltage contactors on/off and it connects the high voltage circuit using the same procedure as the power switch linked operation. (See
Power switch linked operation.)
• When the high voltage battery increases to the specified temperature and the battery heater operation is stopped, the PCM turns off the high voltage contactors and cuts off the high voltage circuit.
Remote climate control/climate control timer linked operation
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• During climate control operation using the remote climate control/climate control timer (cabin preconditioning system), it is necessary to supply power from the high voltage battery to the electric compressor regardless of whether or not the main power is switched OFF or ON (READY off or on). (See
FULL-AUTO AIR CONDITIONER SYSTEM [FULL-AUTO AIR CONDITIONER].)
• When the PCM receives a cabin preconditioning system operation signal from the heat pump control unit via CAN communication, it turns the high voltage contactors on/off and cuts off the high voltage circuit using the same procedure as the power switch linked operation. (See
Power switch linked operation.)
• When the PCM receives a cabin preconditioning system stop signal from the heat pump control unit via CAN communication, it turns off the high voltage contactors and cuts off the high voltage circuit.
Auxiliary device power charging system linked operation
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• Vehicle's electrical devices such as the body control module (BCM) are activated each time the user opens or closes the door even when the main power is switched OFF. Because frequent activation of the vehicle's electrical devices while the main power is switched OFF leads to lead-acid battery depletion, it is necessary to charge the lead-acid battery.
• When the PCM determines that auxiliary device power charging is necessary from the activation state of the vehicle's electrical devices when the main power is switched OFF, it turns the high voltage contactors on/off and connects the high voltage circuit using the same procedure as the power switch linked operation. (See
AUXILIARY DEVICE POWER CHARGING SYSTEM.) (See
Power switch linked operation)
• When the lead-acid battery stops charging, the PCM turns the high voltage contactors off and cuts off the high voltage circuit.
