Polyphase Motor Torque Transition Control Using Optimized Trajectories
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Solution Overview
Problem
Existing electric machine control systems struggle to maximize efficiency during torque transitions, often trading torque performance against transient efficiency due to underutilization of bus voltage and controller output saturation.
Innovation Solution
The implementation of an optimized trajectory calculator in the controller of a polyphase electric machine, which provides switching signals to the power inverter to ensure maximum bus voltage utilization and adherence to Maximum Torque Per Amp (MTPA), Maximum Torque Per Loss (MTPL), Maximum Torque Per Flux (MTPF), or Maximum Torque Per Volt (MTPV) control strategies during torque transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional control systems are used for torque transitions, then the system is simpler to implement, but torque transition efficiency deteriorates due to underutilization of bus voltage and controller output saturation
Solution Approach 1:
The optimized trajectory calculator pre-calculates the optimal torque transition path before the actual transition occurs. By determining the ideal trajectory in advance based on the starting and target torque values, the system can execute the transition efficiently without real-time computational delays or saturation issues, thus improving torque transition efficiency without requiring complex real-time control algorithms
Solution Approach 2:
The system changes the control parameters by implementing an optimized trajectory that dynamically adjusts the torque transition path. Instead of using fixed or conventional control parameters, the trajectory calculator computes optimal parameter values that maximize bus voltage utilization and maintain controller output within safe limits, thereby improving energy efficiency during torque transitions
2Speed
If bus voltage utilization is increased to improve torque response, then torque transition speed improves, but controller output saturation occurs leading to reduced efficiency
Solution Approach 1:
The optimized trajectory calculator incorporates feedback mechanisms by continuously monitoring the current torque state and adjusting the transition trajectory accordingly. This feedback ensures that the controller output remains within optimal ranges, preventing saturation while maintaining high torque transition speed, thus avoiding energy losses associated with controller saturation
Solution Approach 2:
The system implements dynamic control by using an optimized trajectory that adapts to the current operating conditions. The trajectory calculator dynamically adjusts the torque transition path based on real-time parameters, allowing the system to maximize torque transition speed while maintaining controller output within safe and efficient limits, preventing both saturation and underutilization
3Loss of time
If torque transition is optimized for speed, then transient time is reduced, but efficiency deteriorates due to suboptimal control during transient periods
Solution Approach 1:
By pre-calculating the optimal torque transition trajectory before the transition begins, the system eliminates the need for suboptimal real-time control adjustments during the transient period. This preliminary action ensures that the entire transition follows the most efficient path, simultaneously minimizing transition time and maximizing transient efficiency
Solution Approach 2:
The optimized trajectory involves changing the control parameters to follow a specific optimal path during the transient period. Instead of using conventional control parameters that lead to saturation or underutilization, the system applies parameter changes that define an optimal trajectory, achieving both fast transition and high efficiency throughout the transient period
Data Source
AI summary
An electric machine is provided. A polyphase machine is provided. A power inverter is electrically connected to the polyphase machine. A controller is electrically connected to the power inverter, wherein the controller provides switching signals to the power inverter, wherein the controller comprises a trajectory calculator that provides an optimized trajectory for transitioning the polyphase machine from a first torque to a second torque.