HV power-on and power-off
control flow
V5.0
Author：
Audit：
Countersign：
Ratify：
V3.0
V4.0
V5.0
20200812
20200902
20210308
zhanghaibin
1.Modify the control logic and
communication signal, and
follow the current strategy of
B car
zhanghaibin
1.Two modes of "HVReady" and
"Failure" are added to MCU, and
the process is adaptively
modified
2.Modification of judging
conditions for MCU to enter
"Precharge" and "HVReady";
2."BCU" changed to "BMS".
langyanni
1.Remove "Switch the power gear
to START" in BCM swimlane.
2.Remove the 6th condition in
"Whether the consitions for
driving are met"
3.Add "charging gun insert
process" when the vehicle is
"Ready to Drive".
4.In Power off process，remove
"VCU_MCU_StsModeReq=7(EmDisChar
ge)" block and
"VCU_MCU_StsModeReq=2
（Standby）" signal sending.
HV power-on control flow
BCM
VCU
Switch the power gear to
ON or START
Sleep
BMS
DCDC
Sleep
Sleep
KL15 ON
KL15 ON
MCU
IPC
Sleep
Remarks
Sleep
KL15 ON
KL15 ON
KL15 ON
The VCU, BMS, DCDC, MCU,
IPC can be woken up by KL15 or
NM message, Initialization can be
started after waking up.
Send hard wire signal
NM message
NM message
NM message
NM message
NM message
Send CAN signal
Wake_Up
Wake_Up
Wake_Up
Wake_Up
Initialization completed
Initialization completed
Initialization completed
Initialization completed
Wake_Up
Initialization completed
BMS_HVOnOff_STS=0（HV Off）
Request for HV power
Record the ST ART request
Send CAN signal
After the VCU is awakened by
KL15, if BCM_Powermode=2 or 3
is detected, the following process
will be executed;
if BCM_Powermode≠2 or 3, the
following process will not be
executed.
BMS_ERR_LEV＜4
BCM_PowerMode=2 or 3（ON or START）
BMS_HVIL_Err=0（Closed）
Send CAN signal
BMS_Sys_STS=1（Self-check-passes）
BMS_ISU_Status=0（Normal）
ACM_CrashOutputSts=0
（No Crash)
Send CAN signal
MCU_FailGrade_ERR＜4
MCU_HVIL_STS=0（Closed）
DCDC_Sys_STS = 1
（Self-Check passes）
Send CAN signal
Request for HV Power:
1. BCM_Powermode=2 or 3.
2. Cooling or heating request.
3. LV/HV charging request.
Record START request when any
of below conditions is met:
1. BCM_Powermode=3.
2. Received ‘START’ hardware
signal.
VCU_BMS_HVOnOff_RE Q=1（allow）
Send CAN signal
Send CAN signal
Close the main negative relay
BMS_TotalNegRelay_STS=2
（Closed）
MCU_Work_STS=2
（Standby）
Send CAN signal
Close the precharge relay
No
BMS_PreChgRelay_STS=2
（Closed）
Send CAN signal
BMS_HVOnOff_STS=1
（PreCharge）
Send CAN signal
No
Check whether the external
terminal voltage reaches 95%
of the internal terminal
voltage within 500ms？
Start timing from closing
the precharge relay
MCU_bus_Volt>0.75*BM
S_Pack_Vol_MEAS？
Yes
BMS_HVOnOff_STS=3
（Fail To HV ON）
BMS_MainPosRelay_STS=2
（Closed）
Yes
Close the main positive relay
Send CAN signal
MCU_Work_STS=3
（PreCharge）
Send CAN signal
The MCU enters the "Failure"
mode when any of the following
conditions are met:
1.MCU_FailGrade_ERR =3
（Torque limit to 0 fault occurs）
2.MCU_FailGrade_ERR=4
3.MCU_FailGrade_ERR=5
Open the precharge relay
No
BMS_HVOnOff_STS=2（HV ON）
MCU_bus_Volt>0.95*BMS_Pac
k_Vol_MEAS&&
BMS_Sys_STS==Successful
High Voltage Power up？
Send CAN signal
BMS_Sys_STS=2
（Successful High Voltage
Power Up）
No
Send CAN signal
Receive
BMS_HVOnOff_STS
=2 within 5s？
Yes
Start timing when VCU Send
VCU_BMS_HVOnOff_RE Q=1
Send CAN signal
BMS_PreChgRelay_STS=1
（Open）
Yes
C1
VCU_VehicleHVStatus=0
（Not Ready）
VCU_BMS_HVOnOff_RE Q=0
（Forbid）
MCU_Work_STS=5
（HVReady）
VCU_DCDC_Outvoltage_RE Q
=14V
VCU_DCDC_Output_RE Q=1
（Enable）
Send CAN signal
VCU_VehicleHVStatus=1
（HV On）
DCDC enters working state
Send CAN signal
No
Whether the conditions for driving are met：
1.VCU_VehicleHVStatus=1（HV On）；
2.VCU recorded the START request;
3.VCU_IMMO_Sts=1（pass）;
4.VCU_ACChgGunln=0（disconnect ）;
5.VCU_DCChgGunln=0（disconnect）;
6.VCU needs to monitor the Start signal entered by the hardwire；
7.Gear must be kept at N / P;
DCDC_Output_STS=1
（Normal）
D1
Yes
VCU_MCU_StsModeReq=4
（Normal）
Send CAN signal
No
Receive
VCU_MCU_StsMode
Req=4？
When the vehicle is already in
"Ready to Drive", if VCU detects
that the charging gun is connected,
it should send
VCU_MCU_StsModeReq=5
（HVReady）
Yes
Send CAN signal
MCU_Work_STS=4（Normal）
Start timing when VCU Send
VCU_MCU_StsModeReq=4
No
Send CAN signal
Receive MCU_Work_STS=4
within 1s?
Yes
VCU_VehicleHVStatus=0
（Not Ready）
VCU_VehicleHVStatus=2（Ready To Drive）
Lamp prompt:
Lighten ready lamp
Send CAN signal
VCU_ACChgGunln=1 or
VCU_DCChgGunln=1
（connect）
VCU_VehicleHVStatus=1（HV On）
Lamp prompt:
Turn-off ready lamp
Send CAN signal
VCU_MCU_StsModeReq=5
（HVReady）
No
Receive
VCU_MCU_StsMode
Req=5？
HV On hold for
AC/DC Charging Process
Yes
VCU_ACChgGunln=0 and
VCU_DCChgGunln=0
（disconnect）
Send CAN signal
TBC
MCU_Work_STS=5
（HVReady）
Send CAN signal
VCU_MCU_StsModeReq=4
（Normal）
Receive
VCU_MCU_StsMode
Req=4？
No
Yes
MCU_Work_STS=4
（Normal）
Send CAN signal
VCU_VehicleHVStatus=2（Ready To Drive）
Lamp prompt:
Lighten ready lamp
Send CAN signal
A1
B1
E1
F1
HV power-off control flow
BCM
VCU
BMS
DCDC
MCU
IPC
A1
B1
C1
D1
E1
Switch the power gear to
ACC or OFF
RE ADY
HV On
Normal
Normal or HVReady
Remarks
F1
KL15 OFF
Send hard wire signal
BCM_PowerMode=0 or 1（OFF or ACC）
Send CAN signal
No
No
power gear is ACC or
OFF？
MCU_FailGrade_ERR
≥4？
Yes
No
BMS_ERR_LEV
≥4？
Yes
Yes
VCU_VehicleHVStatus=0
（Not Ready）
Lamp prompt:
Turn off ready lamp
Send CAN signal
VCU_MCU_StsModeReq=11
（Shut Down）
VCU_DCDC_Output_RE Q=0
（Disable）
VCU_EACEnbReq=0
（Disable）
No
No
BMS_PackCur_MEAS
is less than 5A？
Is the time longer than
10s？
Yes
Exit normal mode
Enter shutdown mode
DCDC stop work
Start timing when VCU send
VCU_VehicleHVStatus=0
Yes
Emergency power off:
When any of the following
conditions are met, the timeout
time is 0.1s:
1.BMS_ERR_LEV =5;
2.ACM_CrashOutputSts≠0;
3.BMS_HVIL_STS=open &&
ABS_VehSpd<5km/h；
4.MCU_HVIL_STS=open &&
ABS_VehSpd<5km/h
5.BMS_IDU_Status=level3
Send CAN signal
MCU_Work_STS=B
（Shut Down）
Send CAN signal
VCU_BMS_HVOnOff_RE Q=0（forbid）
Send CAN signal
DCDC_Output_STS=0
（Stop）
The MCU automatically enters
ActDisChg when the following
conditions are met:
1.ACM_CrashOutputSts=Crash;
2.BMS_MainPosRelay_STS=Open
is satisfied in 90ms, or the time is
over 90ms。
Open the main positive relay
BMS_MainPosRelay_STS=1
（Open）
Send CAN signal
Open the main negative relay
BMS_HVOnOff_STS=0（HV OFF）
Send CAN signal
BMS_TotalNegRelay_STS=1
（Open）
No
Start timing when VCU send
VCU_BMS_HVOnOff_RE Q=0
No
BMS_HVOnOff_STS=0&
MCU_spd<100rpm&
MCU_spdValid=Valid？
Is the time over 10s？
Yes
Yes
Send CAN signal
MCU_disxhg_st=0（NO Active Discharge）
MCU_Work_STS=B（Shut Down）
No
Send CAN signal
VCU_MCU_StsMode
Req=11 and
BMS_MainPosRelay_
STS=1 and
MCU_Spd<1500rpm
Yes
Enter active discharge
MCU_disxhg_st=1（Active Discharge）
Send CAN signal
Start timing when MCU send
MCU_disxhg_st=1
No
MCU_disxhg_st=2（Failed Active Discharge）
Send CAN signal
The voltage drops
below 60V within 2s?
Yes
MCU_disxhg_st=3（Finished Active Discharge）
Send CAN signal
No
No
MCU_bus_
Volt<60?
Yes
Stored data
According to NM,Prepare to
sleep
No
MCU_disxhg_st =
2?
Yes
No
MCU_disxhg_st
= 3?
Yes
the time of
active discharge
is over 5s?
Yes
Start timing when VCU
receive MCU_disxhg_st=1
Stored data
According to NM,Prepare to
sleep
Stored data
According to NM,Prepare to
sleep
Stored data
According to NM,Prepare to
sleep
When the following conditions are
met，MCU enter
FailActDisChg：
1.the condition of
VCU_MCU_StsModeReq=ShutDo
wn and
BMS_MainPosRelay_STS=closed
and MCU_Spd<1500rpm and this
state is over 15seconds;
2.MCU_Work_STS= ShuntDown
and when the time of active
discharge is over 2s, while the
voltage of MCU is still over 60V。