PMSM Actuation Using Polynomial d-q Current Point Selection
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Solution Overview
Problem
Existing methods for actuating permanent magnet synchronous motors in brake systems of motor vehicles are complex and require significant computing power, making them difficult to implement simply in microcontrollers and adaptable to different motor designs.
Innovation Solution
A method for actuating a permanent magnet synchronous motor that involves determining two initial d-q current points, connecting them with a polynomial, and finding intersections with power and torque limit curves to select an optimal operating point that balances torque requirement and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If complex control algorithms are used to precisely control the permanent magnet synchronous motor, then the torque requirement can be met and voltage reserve is controlled, but the device complexity and computing power requirements increase significantly
Solution Approach 1:
The patent transforms the control problem from direct torque control to d-q current control in a rotating coordinate system. By changing the reference frame parameters and using coordinate transformation (Park transformation), the control algorithm simplifies the calculation while maintaining precision. The d-q current components are calculated based on torque requirement and voltage reserve, avoiding complex direct torque control algorithms.
Solution Approach 2:
The patent introduces a two-axis d-q coordinate system that rotates with the rotor, transforming the three-phase AC control problem into a two-component DC-like control problem. This dimensional transformation simplifies the control algorithm by separating the torque-producing current component (q-axis) from the flux-producing current component (d-axis), reducing computational complexity while maintaining control precision.
2Power
If the permanent magnet synchronous motor is operated at high power to meet torque requirements, then the torque output is sufficient, but the power consumption may exceed the maximum permissible power of the vehicle electrical system
Solution Approach 1:
The patent implements a control algorithm that continuously monitors the voltage reserve and adjusts the d-q current components accordingly. By using feedback on the actual voltage conditions and comparing with the maximum permissible power limit, the controller dynamically optimizes the current distribution between d-axis and q-axis components, ensuring torque requirements are met while staying within power constraints.
Solution Approach 2:
The control algorithm dynamically adjusts the d-q current components based on real-time operating conditions. The q-axis current (torque-producing) and d-axis current (flux-producing) are continuously optimized to achieve the required torque with minimum power consumption. This dynamic adjustment allows the motor to operate efficiently across different loading conditions without exceeding the electrical system's power limits.
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
The method allows for a simple and efficient actuation of permanent magnet synchronous motors, reducing computing requirements and enabling adaptation to various motor designs while achieving optimal torque and energy efficiency.
Implementation Method 1
controlled voltages or currents can be fed to the synchronous motor and generate a rotating or stator field at the stator, which can bring about a torque in the rotor
Data Source
AI summary
A method for actuating a permanent magnet synchronous motor is disclosed. The method provides simplifications in the calculations required for the control in order to reduce the computing time while at the same time achieving the lowest possible deviation from the optimum d-q current point or current vector. A permanent magnet synchronous motor suitable for carrying out the method is also disclosed.