Three-Phase Motor Flux Control With Load-Angle Torque Regulation
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Solution Overview
Problem
Current control systems for three-phase electric machines are complex and require high computational power and memory, making them costly and inefficient, especially when controlling torque across a wide range of operating conditions and voltage/current constraints.
Innovation Solution
A method and system that control a three-phase electric machine by directly managing the stator magnetic flux in terms of amplitude and load angle, using a simple load angle look-up table to generate control signals for the inverter, reducing computational complexity and memory requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional current vector control or multidimensional look-up tables are used to control three-phase electric machines, then the machine can be controlled across a broad range of operating conditions, but the control system complexity and computational power requirements increase significantly
Solution Approach 1:
The patent transforms the control approach by changing the controlled parameters from current-based control to direct magnetic flux control. By controlling the amplitude and load angle of the stator magnetic flux directly, the system achieves broad operating range adaptability while simplifying the control algorithm structure and reducing computational requirements.
Solution Approach 2:
The patent replaces complex computational mechanisms (multidimensional LUTs and iterative algorithms) with a simplified direct control mechanism. By using analytical expressions to directly calculate the required stator voltage components from desired magnetic flux parameters, the system eliminates the need for complex lookup tables and iterative computations while maintaining versatility across operating conditions.
2Productivity
If complex control algorithms are used to manage voltage and current constraints, then high dynamic performance is achieved, but computational power requirements and system costs increase
Solution Approach 1:
The patent extracts and directly controls the essential magnetic flux parameters (amplitude and load angle) that determine dynamic performance, separating them from the complex current control calculations. By focusing control efforts on these key parameters through direct analytical expressions, the system achieves high dynamic performance while eliminating unnecessary computational complexity.
Solution Approach 2:
The patent performs preliminary calculation of the required stator voltage components using direct analytical expressions before actual control execution. By pre-calculating the voltage components from desired magnetic flux parameters, the system prepares control actions in advance with minimal computation, enabling high dynamic response without requiring extensive real-time computational power.
3Ease of manufacture
If multidimensional look-up tables are used to simplify control algorithms, then ease of implementation improves, but memory requirements and device costs increase substantially
Solution Approach 1:
The patent replaces expensive, large-capacity memory storage (multidimensional LUTs) with simple analytical expressions that require minimal memory. By using direct calculation formulas to determine stator voltage components from operating parameters, the system achieves ease of implementation through straightforward mathematics rather than through large lookup tables, dramatically reducing memory requirements and device costs.
Data Source
AI summary
A method for controlling a three-phase electric machine by a control unit operatively connected to a controller, to a sensor, and to an inverter includes: a first acquisition phase, wherein the control unit receives, from the controller, a first signal representative of a reference torque; a second acquisition phase, wherein the control unit receives, from the sensor, at least one further signal representative or one or more of the following quantities: an electric quantity of the inverter, an electric quantity of the three-phase electric machine, and a mechanical quantity of the three-phase electric machine; a control phase, wherein the control unit generates a control signal that it inputted to the inverter for generating an effective torque of the three-phase electric machine, wherein the control signal is determined on the basis of a reference stator voltage, wherein the reference stator voltage is determined by the control unit as a function of a reference amplitude value and a reference load angle value of a stator magnetic flux vector of the three-phase electric machine.