Pulsed Rotor Flux Control in Polyphase Machines to Cut Losses
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Solution Overview
Problem
Conventional electric machines operate inefficiently under varying load conditions due to transient periods and high bandwidth torque control, leading to suboptimal control and increased energy consumption.
Innovation Solution
Implementing a control strategy that pulses the torque between demand levels, allowing the rotor flux to naturally decay between pulses, thereby optimizing the inverter and copper losses while maintaining efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high bandwidth torque control is used to achieve fast torque response, then torque control precision is improved, but energy consumption increases and transient losses increase
Solution Approach 1:
The patent applies periodic pulsed torque control instead of continuous high bandwidth control. The controller pulses the torque between demand levels, allowing the rotor flux to naturally decay between pulses. This periodic action reduces inverter and copper losses while maintaining the required torque precision through controlled pulsing at optimized frequencies and duty cycles.
2Stability of the object's composition
If continuous torque operation is maintained to ensure smooth mechanical output, then mechanical stability is improved, but total energy losses increase
Solution Approach 1:
The system uses periodic pulsed torque control where the torque is applied in controlled pulses rather than continuously. The pulse frequency and duty cycle are optimized to maintain smooth mechanical output while reducing total losses by allowing the rotor flux to naturally decay between pulses, eliminating continuous inverter and copper losses.
Solution Approach 2:
The patent changes the operational parameters by pulsing the torque between different demand levels (first and second demand torque levels) rather than maintaining a constant level. This parameter modulation allows the system to achieve the required average torque output while reducing energy losses through controlled intermittent operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Reduces total losses by up to 7% compared to continuous operation, enhancing energy conversion efficiency and reducing noise and vibration.
Implementation Method 1
A polyphase machine comprising at least one of an induction machine and an externally excited synchronous machine connected to a power inverter
Implementation Method 2
the torque signal provides a plurality of pulses that pulse between a first demand torque level and a second demand torque level... when the torque signal is at the first demand torque level, rotor flux strictly increases and when the torque signal is at the second demand torque level, rotor flux strictly decreases
Data Source
AI summary
An electric machine is provided. A polyphase machine comprising at least one of an induction machine and an externally excited synchronous machine is provided. A power inverter is electrically connected to the polyphase machine. An inverter controller is electrically connected to the power inverter, wherein the inverter controller is configured to provide a torque command, wherein the torque command provides a torque signal to provide a plurality of pulses that pulse between a first demand torque level and a second demand torque level, wherein the second demand torque level is lower in amplitude than an amplitude of the first demand torque level and control an id provided by the power inverter, so that when the torque signal is at the first demand torque level, rotor flux strictly increases and when the torque signal is at the second demand torque level, rotor flux strictly decreases.