Synchronous Machine Saturation Profiling for Sensorless Rotor Position
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Solution Overview
Problem
Existing methods for controlling synchronous machines without position sensors require complex parameter determination and load test stands, increasing time and complexity, especially for accurate rotor position assignment at low rotational speeds or standstill conditions.
Innovation Solution
A method involving cyclic measurement of current during pulse width modulation with macroscopic flux pulses to derive rotor position assignment parameters without a load test stand, using macroscopic flux pulses to momentarily increase current and torque, allowing parameter determination without affecting rotor position significantly, and subsequent injection cycles for admittance/inductance measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If sensor-less control methods are used to avoid position sensors, then system costs and installation space are reduced, but parameter determination becomes more complex and time-consuming
Solution Approach 1:
The patent applies preliminary action by performing parameter determination during the commissioning phase before the machine enters normal operation. All necessary parameters including saturation profiles are measured in advance using a simplified procedure without load test stands, storing them for later use during operation. This eliminates the need for complex real-time parameter determination.
Solution Approach 2:
The machine performs self-service by automatically determining its own parameters during commissioning without requiring external test equipment or load test stands. The control device executes automated measurement sequences that capture saturation profiles and other parameters, making the system self-sufficient and eliminating dependency on complex external testing infrastructure.
2Measurement precision
If macroscopic flux pulses are applied to determine saturation profiles, then accurate rotor position assignment is achieved, but current and torque increase momentarily
Solution Approach 1:
The patent applies periodic action by using pulsed flux excitation instead of continuous excitation. Macroscopic flux pulses are applied periodically during commissioning to probe the saturation characteristics at different rotor positions. This pulsed approach allows accurate measurement of saturation profiles while limiting the duration of high current and torque, preventing significant rotor position changes during measurement.
Solution Approach 2:
The patent applies parameter changes by systematically varying the flux pulse magnitude and duration to map out the saturation profile. By changing the excitation parameters and measuring the corresponding current response, the system accurately determines the saturation characteristics without requiring sustained high torque conditions, thus achieving measurement precision while controlling the mechanical stress.
3Measurement precision
If load test stands are used for parameter determination, then accurate saturation profiles are obtained, but device complexity and installation requirements increase
Solution Approach 1:
The patent applies the extraction principle by removing the load test stand from the measurement system. Instead of requiring external test equipment, the method extracts the necessary measurement capability directly from the machine itself by using the control device to apply flux pulses and measure current response. This eliminates complex external testing infrastructure while maintaining measurement accuracy.
Solution Approach 2:
The control device performs multiple functions: it acts as both the controller for normal operation and the measurement instrument for parameter determination. The same control device that manages motor control also executes the saturation profile measurement sequences, eliminating the need for separate dedicated test equipment and reducing overall system complexity.
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
Enables unambiguous rotor position assignment and control of synchronous machines without position sensors, reducing complexity and time consumption, and allowing operation across various rotational speeds, including low speeds and standstill conditions.
Implementation Method 1
The synchronous machine is actuated by clocked terminal voltages according to the pulse width modulation process
Implementation Method 2
applying macroscopic flux pulses which allow the current to momentarily increase into a range that can change a magnetic saturation state of the synchronous machine
Implementation Method 3
the current of the synchronous machine is measured cyclically
Data Source
AI summary
A method for measuring magnetic saturation profiles of a synchronous machine having a rotor and a stator includes actuating the synchronous machine with clocked terminal voltages according to a pulse width modulation process. The method further includes cyclically measuring a current of the synchronous machine resulting from the synchronous machine being actuated by the clocked terminal voltages. The method further includes applying macroscopic flux pulses which allow the current to momentarily increase into a range that can change a magnetic saturation state of the synchronous machine.