Settings

Protections

The BMS Main X monitors the battery modules, compares the voltages and currents of the modules, and protects the battery system from damage.

Charging current limit

The BMS Main X device protects the battery from charging current higher than estimated current limit.

To configure parameters of the charge current limit, select the "Protections → Charge current limit" section:

In this section:

• Enable – a flag to enable the protection;
• Threshold to switch from Region 1 to Region 2 – a threshold current value, dividing regions 1 and 2 with their error generation conditions, A;
• Region 1: Current difference – an absolute difference of measured battery current and calculated value “Charge current limit”, at which error is generated (condition for Region 1), A;
• Region 2: Current difference – a relative difference of measured battery current and calculated value “Charge current limit”, at which error is generated (conditions for Region 2), %;
• Delay before setting the error, millisecond;
• Delay before clearing the error, second;
• Lock – a flag to block the error until the device is restarted.

As a result of the operation of the charging current limit protection, the “Current limit error (CH)” is generated.

Error generation conditions:

• if the current is positive, less than “Threshold to switch from Region 1 to Region 2” value and exceeds “Charge current limit” by the “Region 1: Current difference” value during the “Delay before setting the error” time;
• if the current is positive, more than “Threshold to switch from Region 1 to Region 2” value and exceeds “Charge current limit” by the (“Region 2: Current difference” × “Charge current limit”) / 100 value during the “Delay before setting the error” time.

Error is cleared if conditions for generating an error do not apply during the “Delay before clearing the error” time.

Discharging current limit

The BMS Main X device protects the battery from discharging current higher than estimated current limit.

To configure parameters of the charge current limit, select the "Protections → Discharge current limit " section:

In this section:

• Enable – a flag to enable the protection;
• Threshold to switch from Region 1 to Region 2 – a threshold current value, dividing regions 1 and 2 with their error generation conditions, A;
• Region 1: Current difference – an absolute difference of measured battery current and calculated value “Discharge current limit”, at which error is generated (condition for Region 1), A;
• Region 2: Current difference – a relative difference of measured battery current and calculated value “Discharge current limit”, at which error is generated (conditions for Region 2), %;
• Delay before setting the error, millisecond;
• Delay before clearing the error, second;
• Lock – a flag to block the error until the device is restarted.

As a result of the operation of the charging current limit protection, the “Current limit error (DCH)” is generated.

Error generation conditions:

• if the current is negative, and the current modulus is less than “Threshold to switch from Region 1 to Region 2” value and exceeds “Discharge current limit” by the “Region 1: Current difference” value during the “Delay before setting the error” time;
• if the current is negative, and the current modulus is more than “Threshold to switch from Region 1 to Region 2” value and exceeds “Discharge current limit” by the (“Region 2: Current difference” × “Discharge current limit”) / 100 value during the “Delay before setting the error” time.

Error is cleared if conditions for generating an error do not apply during the “Delay before clearing the error” time.

Battery cover

The BMS Main X device detects the opening of the battery cover and performs a protective opening of the contactors.

Battery cover protection is configured in the "Protections - Battery cover" section:

In this section:

• Enable – a flag to enable the protection;
• Delay before setting the error;
• Delay before clearing the error;
• Lock – a flag to block the error until the device is restarted.

As a result of the protection against opening the battery cover, the “Battery cover” error is generated. Conditions for generating the error:

• presence of the “Battery cover” signal during the “Delay before setting the error” time.

Conditions for clearing the error:

• no “Battery cover” signal during the “Delay before clearing the error” time.

Insulation

The BMS Main X device detects a signal from an external insulation monitoring device (e.g., Bender IR155) and performs a protective opening of the contactors.

Insulation protection is configured in the "Protections - Insulation" section:

In this section:

• Enable – a flag to enable the protection;
• Checking algorithm – isolation checking mode:
  • Always on – check is always performed;
  • On charging – check is performed only if the “Charge request” is set;
  • Except charging - check is performed only if the “Charge request” is cleared;
• Delay before setting the error, second;
• Delay before clearing the error, second;
• Lock – a flag to block the error until the device is restarted.

The “Insulation fault” is set if the “Insulation status” signal is detected during the “Delay before setting the error” time. The “Insulation status” signal can be received through the discrete input or by the CAN bus from an insulation monitoring device. The “Insulation fault” is cleared if the “Insulation status” signal is cleared during the “Delay before clearing the error” time.

Contactor feedback

The BMS Main X device detects the feedback signals from the main contactors and, in the event of a discrepancy between the feedback signals from the control signals, performs a protective opening of the contactors.

Contactor feedback protection is configured in the “Protections – Contactor feedback” section:

In this section:

• Enable – a flag to enable the protection;
• Delay before setting the error;
• Delay before clearing the error;
• Lock – a flag to block the error until the device is restarted.

As a result of the protection against contactor failures, the errors "CH contactor feedback error", "DCH contactor feedback error", "CH/DCH contactor feedback error" are generated. Conditions for generating the errors:

• feedback signal from the contactor differs from the contactor control signal for the time "Delay before setting the error".

Conditions for clearing the error:

• feedback signal from the contactor repeats the contactor control signal for the time "Delay before clearing the error".

Module offline

The BMS Main X device detects the loss of communication with the battery modules and performs a protective opening of the contactors.

Protection against loss of communication with battery modules is configured in the "Protections - Module offline" section:

In this section:

• Enable – a flag to enable the protection;
• Number of offline modules to set the error;
• Delay before setting the error, second;
• Delay before clearing the error, second;
• Lock – lock the error until the device is reset.

As a result of the protection from loss of communication with battery modules, the "Module offline" error is generated.

Error generation conditions:

• more than “Number of offline modules to set the error” battery modules do not respond to the commands of the BMS Main X device within “Delay before setting the error” time.

Conditions for removing the error:

• less than “Number of offline modules to set the error” battery modules do not respond to the commands of the BMS Main X device within “Delay before clearing the error” time.

Voltage unbalance (in any state)

Before closing the contactors for charging and discharging battery modules, the BMS Main X device detects those modules whose voltage is significantly different from the rest. For unbalanced modules, errors "Voltage unbalance (CH)" (charge circuit) and "Voltage unbalance (DCH)" (discharge circuit) are generated.

Protection against voltage unbalance of battery modules is configured in the section "Protections - Voltage unbalance (in any state)":

In this section:

• Enable – a flag to enable the protection;
• Delta voltage – maximum allowable voltage difference of battery modules, V;
• Use the open circuit voltage to detect the error – a flag to use the U_ocv (corrected due to current and module resistance) module voltage;
• Delay before setting the error;
• Delay before clearing the error;
• Set the 'Voltage unbalance' error for the modules that are not ready to charge/discharge;
• Lock – a flag to block the error until the device is restarted.

As a result of the operation of the voltage unbalance protection the errors “Voltage unbalance (CH)” and “Voltage unbalance (DCH)” are generated.

Conditions for generating the error:

• battery module is not included in the largest group of modules whose voltages differ from each other by no more than "Delta voltage" during the "Delay before setting the error" time;
• module is not ready to charge or discharge;

Conditions for clearing the error:

• battery module is in the largest group of balanced modules during the "Delay before clearing the error" time;
• module is ready to charge or discharge.

Current unbalance (in “Balancing” state)

When battery modules are connected in parallel, the most charged modules transfer charge to the least charged modules. The process of charge transfer is accompanied by the flow of balancing currents. The BMS Main X device detects modules with high balancing currents and generates “Current unbalance (CH)” (charge circuit) and “Current unbalance (DCH)” (discharge circuit) errors for them.

Protection against current unbalance of battery modules is configured in the section "Protections - Current unbalance":

In this section:

• Enable – a flag to enable the protection;
• Maximum current – a maximum allowable self-balancing current of battery modules, A;
• Delay before setting the error;
• Delay before clearing the error;
• Check all the time (not only in the ‘Balancing’ state) – a flag to enable voltage check not only in “Balancing” state;
• Lock – a flag to block the error until the device is restarted.

As a result of the operation of the current unbalance protection the errors “Current unbalance (CH)” and “Current unbalance (DCH)” are generated.

Conditions for generating the error:

• the current of the battery module is greater than the "Maximum current" value during the "Delay before setting the error" time.

Conditions for clearing the error:

• the current of the battery module is less than the "Maximum current" value during the "Delay before clearing the error" time.

Charging current unbalance (in “Charging” state)

During battery charging, the currents of the battery modules may vary. The BMS Main X device detects modules whose charging currents are significantly different from the currents of other modules and generates the “Charging current unbalance” errors for them.

Protection against different charge currents is configured in the "Protections – Charging current unbalance" section:

In this section:

• Enable – a flag to enable the protection;
• Delta current – maximum allowable charge current difference, A;
• Delay before setting the error;
• Delay before clearing the error;
• Lock – a flag to block the error until the device is restarted.

As a result of the operation of the protection the “Charging current unbalance” are generated.

Conditions for generating the errors:

• battery module is not included in the largest group of modules whose charge currents differ from each other by no more than "Delta current" during the "Delay before setting the error" time.

Conditions for clearing the error:

• battery module is included in the largest group of modules with similar charge currents during the “Delay before clearing the error” time.

Discharging current unbalance (in “Discharging” state)

During battery discharging, the currents of the battery modules may vary. The BMS Main X device detects modules whose discharging currents are significantly different from the currents of other modules and generates the “Discharging current unbalance” errors for them.

Protection against different discharge currents is configured in the "Protections – Discharging current unbalance" section:

In this section:

• Enable – a flag to enable the protection;
• Delta current – maximum allowable discharge current difference, A;
• Delay before setting the error;
• Delay before clearing the error;
• Lock – a flag to block the error until the device is restarted.

As a result of the operation of the protection the “Discharging current unbalance” are generated.

Conditions for generating the errors:

• battery module is not included in the largest group of modules whose discharge currents differ from each other by no more than "Delta current" during the "Delay before setting the error" time.

Conditions for clearing the error:

• battery module is included in the largest group of modules with similar discharge currents during the “Delay before clearing the error” time.

High contactor temperature

The BMS Main X device protects power contactors from overheating. To measure the temperature of the contactor, one of the thermistors connected to the X5 connector is used.

To change the overheating protection parameters of power contactors, select the "Protections → High contactor temperature" section:

In this section:

• Enable – a flag to enable the protection;
• Thermistor – a selection of which cell thermistor will be used as contactor temperature sensor;
• Maximum contactor temperature, °C;
• Tolerant contactor temperature, °C;
• Delay before setting the error, second;
• Delay before clearing the error, second;
• Lock – a flag to block the error until the device is restarted.

If there is a contactor overheat, the "High contactor temperature" error is generated.

Error generation conditions:

• the contactor temperature is greater than the “Maximum contactor temperature” value during the “Delay before setting the error” time.

Conditions for removing the error:

• the contactor temperature is lower than the “Tolerant contactor temperature” value during the “Delay before clearing the error” time.

WDT reset

If the BMS firmware hangs, the watchdog timer resets the device. The BMS can detect that the device was reset and generates the “WDT reset” error.

To change the parameters of the watchdog protection, select the "Protections → WDT reset" section:

In this section:

• Enable – a flag to enable the protection;
• Delay before clearing the error, second;
• Lock – a flag to block the error until the device is restarted.

Conditions for removing the error:

• the “Delay before clearing the error” time has passed from the device startup.

Critical error

Some of the errors are system critical. A separate signal named "Critical error" indicates a BMS fault.

To change the critical error parameters, select the "Protections → Critical error" section:

In this section:

• Enable – a flag to enable the protection;
• Delay before setting the error;
• Delay before clearing the error;
• Lock – a flag to block the error until the device is restarted.

The "Critical error" signal is generated if at least one of the critical errors (see Errors) is generated during the “Delay before setting the error” time.

The “Critical error" signal is cleared if there are no errors from the list above during the “Delay before clearing the error” time.