Multi-Motor EV Power Control for Partial-Load Motor Deactivation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power management systems for electric vehicles with multiple electric motors often operate all motors at partial load inefficiently, leading to reduced efficiency and shorter motor lifetimes, as they typically split power equally among all motors regardless of demand.
Innovation Solution
A power management system that selectively activates or deactivates electric motors based on mechanical power demand, using a mechanical power demand indicator and electrical power demand estimator to optimize torque control and electrical power demand, thereby extending motor efficiency and lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all electric motors are kept active during partial load conditions, then the powertrain can meet varying power demands, but the efficiency and lifetime of the motors are reduced due to operation at suboptimal load points
Solution Approach 1:
The system dynamically adjusts the number of active motors based on real-time power demand assessment. The mechanical power demand indicator and electrical power demand estimator enable the system to transition between different motor activation states, optimizing the balance between reliability and productivity by keeping motors active only when necessary.
Solution Approach 2:
The system changes the operational parameters by deactivating motors under specific conditions. By monitoring mechanical power demand and comparing it against thresholds, the system alters the state of motor activation to maintain optimal efficiency points, thereby extending motor lifetime while preserving sufficient power delivery capability.
2Power
If multiple electric motors operate simultaneously, then the powertrain can deliver high power output, but the electrical power demand increases unnecessarily during partial load conditions
Solution Approach 1:
The system applies partial action by activating only the necessary number of motors required to meet the current power demand. Instead of running all motors continuously, the system calculates the minimum number of motors needed based on mechanical power demand indicators, thereby reducing electrical power consumption while maintaining sufficient power output capability.
Solution Approach 2:
The system uses feedback from mechanical power demand indicators and electrical power demand estimators to continuously monitor and adjust motor activation. This closed-loop control ensures that motors are activated or deactivated based on actual power requirements, optimizing the balance between power output and electrical power demand.
3Loss of energy
If the power management system deactivates motors to reduce electrical power demand, then efficiency improves, but the system must accurately estimate power demand to avoid insufficient power delivery
Solution Approach 1:
The system performs preliminary assessment of power demand using mechanical power demand indicators and electrical power demand estimators before making motor activation decisions. This advance estimation allows the system to predict whether deactivating motors will compromise power delivery capability, enabling efficient energy management while avoiding insufficient power delivery.
Solution Approach 2:
The system continuously monitors power demand parameters and uses this feedback to adjust motor activation decisions. By comparing estimated electrical power demand against actual conditions, the system can accurately determine when motor deactivation is safe, thereby improving energy efficiency without compromising power delivery reliability.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
It is aimed to provide a power management system for an electrically driven vehicle that comprises a powertrain of at least two electric motors that can be selectively geared into the powertrain and an electric power source for powering the at least two electric motors. The power management system comprises a mechanical power demand indicator, indicating a level of mechanical power demanded from the powertrain, and an electrical power demand estimator, arranged to estimate an electrical power demand from the electric power source of a respective one of the at least two electrical motors as a function of the demanded mechanical power. The power management system is arranged to activate or deactivate a respective one of said at least two electric motors in response to the mechanical power demand indicator. The power management system is further arranged to deactivate a respective one of the at least two electric motors when the power management system detects that the demanded mechanical power does not exceed a maximum value for the powertrain having a respective one of said at least two electric motors deactivated; and that the estimated electric power demanded by the powertrain having the respective one of said at least two electric motors deactivated, is lower than the powertrain having the respective one of said at least two electric motors activated; or otherwise activate the respective one of the at least two electric motors.