Cell Voltage Low-Pass Filter; Cell Open Wire Detection And Diagnostics - Nuvation Energy NUV300-BC-12 Product Manual

For some applications, it may be desirable to de-rate the effective passive balancing current by
increasing the balancing settling period as a way to decrease the balancing duty cycle. If the
balancing settling period is increased beyond the scan period, the actual scan rate of the system will
start to decrease below the configured value. If this is increased even further, the reduced scan
period will eventually trip the scan rate watchdog, putting the system into the fault state.

7.10.2. Cell Voltage Low-Pass Filter

One of two low-pass filters (LPF) are available for cell voltage measurement. This cell voltage low-
pass filter is also referred to as the 'Measurement Anti-Aliasing Filter'. The filters are implemented in
hardware and are selected via the following configuration.
sc_linkbus.cell_voltage_lpf_bw
▪
A value of 0 selects a 7 kHz LPF (i.e OFF)
▪
A value of 1 selects a 26 Hz LPF (i.e. ON)

The 7 kHz LPF cannot be used with the Low-Voltage BMS

7.10.3. Cell Open Wire Detection and Diagnostics

The battery management system is capable of detecting wiring and circuit problems on each cell
voltage channel. The following scenarios are detectable:
▪
Open circuits
▪
Short circuits
▪
High impedance connections/wiring
▪
Internal battery management system hardware failures

The Nuvation Energy Low-Voltage BMS can only detect open wires when its low-pass
filter is configured to 7 kHz. Refer to
All channels are scanned for wiring and circuit problems when exiting lockout and during battery
management system power up. Open wires and circuit problems are reported for each cell through
the cell.open_wire flag. The common configurable settings for open wire detection on all modules are
listed and described below.
sc_linkbus.cell_open_wire_disabled
▪
Typically this is set to 0
▪
Setting this to 1 will disable all open wire reporting
sc_linkbus.cell_open_wire_period
▪
The configurable period for scanning all channels for open wires
▪
Typically this is set to 3600000000 (one hour)
Document ID: NE-PM-002
Nuvation Energy Low-Voltage BMS - Product Manual
Section 7.10.2 for details on configuration.
129 Rev 1.2, 2021-03-03
Curie Update 1