Calculation of Parasitic Capacitance to Analyze Shaft Voltage of Electric Motor with Direct-Oil-Cooling System

Abstract

In modern electric vehicles, electrical failure has become a critical problem that reduces the lifetime of traction motors. Moreover, traction motors with high-voltage and high-speed systems for a high power density have been aggravating the shaft voltage problems. This study identifies that direct-oil-cooling systems exacerbate this problem. To address this, an analytical method for calculating parasitic capacitance is proposed to determine the effects of cooling oil in a traction motor with a direct-oil-cooling system. Capacitance equivalent circuits are configured based on whether the slot is submerged in the cooling oil. In addition, an electric field decomposition method is applied to analyze the distortion of the electric field by the structure of the conduction parts in the motor. The results indicate that the parasitic capacitances of the traction motor are increased by the influence of the cooling oil resulting in an increase in the shaft voltage.

Analysis and Optimization of the Fuel Consumption of an Internal Combustion Vehicle by Minimizing the Parasitic Power in the Cooling System

“…The flowchart in Figure 10 shows the complete calculation model, where the inclusion of new input and intermediate data can be seen, in addition to the output now being fuel consumption. For the proposed condition, fuel consumption was calculated by converting the chemical energy between the base and proposed vehicle by the difference in the amount of energy required in the original and proposed configuration into delta chemical energy of the fuel, resulting in a reduction in fuel consumption and mass of fuel burned, according to Equation (7). For the proposed condition, fuel consumption was calculated by converting the chemical energy between the base and proposed vehicle by the difference in the amount of energy required in the original and proposed configuration into delta chemical energy of the fuel, resulting in a reduction in fuel consumption and mass of fuel burned, according to Equation (7).…”

“…There is significant interest in the automotive industry in optimizing energy consumption related to cooling, focusing on minimizing the parasitic power consumed in this process [7,8]. Furthermore, several production applications already incorporate solutions such as PWM electro-fans, brazed radiators with complex geometry and high efficiency, controlled thermostatic valves, and variable water pumps [9,10].…”

“…Nevertheless, this escalation is typically linked to a heightened level of energy consumption. In this context, there is significant interest within the automotive sector in optimizing energy consumption associated with the cooling system, as reflected in the literature [7][8][9]. The primary focus has consistently been on minimizing the parasitic power consumed during this process.…”