Insulation Detection of Electric Vehicles by Using FPGA-Based Recursive-Least-Squares Algorithm

Abstract

The principal reason for why electric vehicles are required to serve as an alternative to the more widespread gasoline and petroleum-based vehicles used in modern times is due to the use of an environmentally conscious means of transportation or to circumvent the tumultuous economic dealings of the compressed natural gas and petroleum industries. There is a growing daily need for large, high-voltage e-mobilities, mostly driven by anticipated advancements in electric vehicle technology. Consequently, all of the various components of these vehicles must be able to be accommodated within a limited and compact space. The battery is an essential component in e-mobility. The insulation, health monitoring, and problem diagnostics of lithium-ion (Li-ion) batteries are of utmost importance in ensuring these vehicles’ safety and efficient functioning. Real-time and fast insulation detection techniques are required to ensure safety in high-voltage (HV) vehicles and to avoid insulation failure. This paper used the Recursive-Least-Squares (RLS) algorithm because it is computationally efficient for building the insulation detection system. Based on the RLS technique, we proposed field programmable gate array (FPGA)-based algorithms and implemented them using VHDL coding. The FPGA is very fast at detection, and the error is lower. We validated the FPGA results with MATLAB simulation results from the existing literature, and the errors are much less when using FPGAs. An experimental hardware platform was also created to validate the proposed FPGA technique with various motor and resistive loadings on electric vehicles (EVs).

FPGA-Based VFF-RLS Algorithm for Battery Insulation Detection in Electric Vehicles

“…The diagram presents the essential configuration of an electric vehicle's high-power supply, comprising the battery circuit module, inverter, motor, disconnectors, and vehicle chassis. Previous studies have examined the origins of the HV system [12][13][14]. The voltage, resistance values, and insulation resistance counting model of the battery are taken into account as input values for the simulation circuit.…”

“…The electrode location [12,15,16] is where the battery pack is most likely to experience the highest leakage current. The insulation resistance between the electrodes and the chassis is crucial for determining the insulation effectiveness of the battery system.…”

“…For the VFF-RLS algorithm, the parameter E(n) is an initial error that is computed at time 'm−1' [12,42]. The subsequent error is given below:…”

“…Therefore, for early detection of insulation status, it is essential to be aware of the factors that can cause insulation breakdown and take appropriate measures to prevent it. Such factors include overload, contamination, aging, physical damage, voltage stress, temperature, and environmental issues like line aging and rain erosion, which might diminish the system's insulation and cause it to fail [10][11][12][13][14]. Figure 1 shows how these factors impact the battery's insulation.…”