Wound Rotor Synchronous Machine Control via State Observer
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Solution Overview
Problem
The control of synchronous electrical machines with wound rotors in electric and hybrid vehicles faces challenges due to the need for multiple mechanical and electrical sensors, which increases cost, size, and reduces reliability.
Innovation Solution
A control device for a three-phase synchronous electric machine with a wound rotor that minimizes sensor usage by incorporating a module for receiving stator and rotor winding voltages, measuring rotor current, and estimating operating parameters using a state observer and Kalman filter, allowing robust control with only a rotor current sensor and a position sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple mechanical and electrical sensors are used to control synchronous electrical machines, then measurement precision and control accuracy are improved, but device complexity, cost, and size increase while reliability decreases
Solution Approach 1:
The patent introduces a state observer as an intermediary computational system that indirectly estimates unmeasured states (currents, torques, positions) from available measurements (voltages and limited sensor data). This mediator approach eliminates the need for multiple direct sensors while maintaining measurement precision through mathematical reconstruction of system states.
Solution Approach 2:
The patent replaces mechanical and electrical sensors with a computational estimation system based on state observers and Kalman filters. This substitution transforms physical measurement devices into software-based mathematical models that compute system states from electrical measurements, thereby reducing hardware complexity and improving reliability.
2Measurement precision
If multiple mechanical and electrical sensors are used to control synchronous electrical machines, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The state observer acts as a computational intermediary that reconstructs complete system state information from minimal sensor measurements. This mediator process replaces multiple physical sensors with mathematical computation, thereby maintaining measurement precision while dramatically reducing device complexity.
Solution Approach 2:
The patent extracts and eliminates unnecessary sensors from the system by using state observers to compute the information that would otherwise require dedicated measurement devices. This extraction principle removes redundant hardware components while preserving the ability to measure all necessary system parameters.
3Measurement precision
If multiple mechanical and electrical sensors are used to control synchronous electrical machines, then measurement precision is improved, but production cost increases
Solution Approach 1:
The patent extracts and removes expensive sensor components from the system architecture. By using state observers to compute currents, torques, and positions from basic voltage measurements and minimal sensor data, the invention eliminates the need for costly current sensors, torque sensors, and position sensors, thereby significantly reducing production cost while maintaining measurement precision.
Solution Approach 2:
The patent replaces expensive, fragile mechanical sensors with computationally intensive but hardware-simple estimation algorithms. The computational model acts as a virtual sensor that provides precise measurements without the cost, size, and reliability issues of physical sensing devices.
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
This approach enables efficient and robust control of synchronous machines with reduced sensor requirements, improving reliability and reducing production costs while maintaining performance, even in the event of sensor failures.
Implementation Method 1
The wound rotor consists of a winding supplied with a direct current (phase f). The amplitude of the field, created in the air gap, is variable and adjustable via the current flowing in the rotor winding. The rotor coil is an electromagnet that seeks to align itself with the rotating magnetic field produced by the stator.
Implementation Method 2
The three-phase stator (phases a, b and c) is constructed in such a way as to generate a rotating magnetic field.
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a control device (4) of a synchronous three-phase electric machine (2) with a wound rotor for an electric motor vehicle or hybrid electric vehicle, which includes a module (6) for receiving voltages (va, vb, vc, vf) at the terminals of the phases of the stator and/or of the winding of the rotor, a module (8) for measuring the current (if) passing through the winding of the rotor, a module (10) for recovering the speed of rotation (ω) of the rotor relative to the stator and an estimator of the behaviour of the operating parameters of the synchronous electric machine (16) with a wound rotor. Moreover, the estimator is combined with the use of a state observer and the control device (4) includes means (14) for collecting reference values of the currents (idref, iqref) passing through the phases of the stator in a two-phase reference frame linked to the rotor (d, q), said estimator (16) being capable of estimating the currents passing through the phases of the stator (id, iq) in the two-phase reference frame linked to the rotor (d, q) in accordance with the magnitudes (va, vb, vc, vf, if, ω) measured by the receiving, measurement and recovery modules (6, 8, 10) and reference values (idref, iqref) of the currents passing through the phases of the stator in a two-phase reference frame linked to the rotor.