Electrically Commutated Machine Position Control via Transmission Gear Ratio
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Solution Overview
Problem
Conventional methods for determining the absolute position of an actuator lever using a single sensor in electrically commutated machines with high transmission gear ratios suffer from imprecision due to transmission play, leading to commutation errors and time-intensive referencing processes.
Innovation Solution
A method and device that determine a comparison value based on the instantaneous angular position of a second gear in the transmission, allowing for precise absolute position determination of the actuator lever and rotor by using additional gears for torque transmission, reducing the influence of transmission play and improving precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single sensor is used to determine absolute position in high transmission gear ratio systems, then device complexity is reduced, but measurement precision deteriorates due to transmission play
Solution Approach 1:
The patent introduces a second gear as an intermediary element between the sensor and the rotor. The sensor measures the angular position of the second gear, which then serves as a mediator to calculate the rotor position through the known transmission gear ratio, eliminating the need for direct rotor position sensing while maintaining precision
Solution Approach 2:
The patent replaces direct mechanical position sensing of the rotor with an indirect measurement approach using gear ratio relationships. Instead of mechanically coupling the sensor to the rotor, the system uses the transmission gear mechanism itself as part of the sensing system, substituting direct mechanical measurement with calculated position based on gear ratios
2Measurement precision
If conventional sensor referencing is used to achieve reliable absolute position determination, then measurement precision is improved, but productivity deteriorates due to time-intensive referencing processes
Solution Approach 1:
The patent performs preliminary determination of the second gear's angular position during normal operation, so that when absolute position information is needed, the calculation can be immediately performed using the already-available second gear position data and the known transmission gear ratio, eliminating time-intensive referencing processes
Solution Approach 2:
The system continuously monitors the angular position of the second gear during normal operation, maintaining ready-to-use position data without interruption. This continuous measurement approach eliminates the need for separate, time-consuming referencing operations, allowing immediate determination of absolute position when required
3Device complexity
If the instantaneous angular position of the second gear is used directly for control, then device complexity is reduced, but reliability deteriorates due to commutation errors from unambiguous position assignment issues
Solution Approach 1:
The patent compares the calculated rotor position (derived from the second gear position and transmission gear ratio) with the actual rotor position obtained from the operating variable. When deviations exceed a threshold, the system modifies the manipulated variable to correct commutation errors, ensuring reliable operation while maintaining simple control system architecture
Data Source
AI summary
A method and device for operating an electrically commutated machine having a rotor on which a first gear of a transmission can be situated, wherein a comparison value is determined as a function of an instantaneous angular position of a second gear of the transmission that is capable of being connected to the first gear for the transmission of torque, and a target value for an manipulated variable of the electrically commutated machine is determined as a function of the result of a comparison of the comparison value with an instantaneous value of an operating variable of the electrically commutated machine.