Brushless DC Motor Control via Static Contactor and Transformer
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Solution Overview
Problem
Existing control methods for brushless DC motors are complex and require sophisticated static converters for voltage calibration and commutation, which can be cumbersome and lack galvanic isolation, especially in applications like aircraft brakes where rotating contacts are needed.
Innovation Solution
A simplified control system using a static contactor with controllable switches that sequences phase voltages based on angular position, integrated with an angular position sensor, and a pulsed voltage generator producing a single-phase voltage of fixed frequency with variable duty cycle, allowing for galvanic isolation via a transformer, thus eliminating the need for rotating contacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a static converter with voltage calibration is used, then the motor control precision is improved, but the device complexity increases
Solution Approach 1:
The patent extracts the voltage calibration function from the static converter, separating it into an independent DC/DC converter. This allows the static converter to focus solely on commutation control, simplifying its structure while maintaining precise motor control through dedicated functions for each component.
Solution Approach 2:
The control system is segmented into two independent parts: a DC/DC converter for voltage calibration and a static converter for commutation. This segmentation allows each component to be optimized for its specific function, reducing overall system complexity while maintaining control precision.
2Reliability
If a static converter is used for commutation, then the motor operation reliability is improved, but the ease of manufacture decreases
Solution Approach 1:
The patent introduces a transformer as an intermediary component between the power source and the motor. This transformer provides galvanic isolation, improving reliability by protecting the control system from electrical disturbances while simplifying manufacturing by using a standard isolation component rather than complex isolation circuits.
3Adaptability or versatility
If rotating contacts are used for power transmission, then the adaptability to rotating applications is improved, but the reliability decreases
Solution Approach 1:
The patent replaces the mechanical rotating contact system with a transformer-based electrical isolation system. This substitution eliminates wear and electrical arcing associated with rotating contacts, significantly improving reliability while maintaining the ability to power rotating motors through the galvanic isolation provided by the transformer.
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 solution simplifies the motor control system, enabling efficient and reliable operation of brushless DC motors in aircraft brakes by providing a compact, contactless power supply that can operate during rotation, supporting multiple modes of operation including braking and autonomous movement.
Implementation Method 1
This pulsed voltage can be transmitted by a transformer, thus achieving galvanic isolation
Data Source
Figure 1~3
AI summary
The method involves associating a static contactor (10) with an electric motor (1) for taking input voltage pulses and delivering polyphase voltage pulses to the motor such that an angular position of a rotor of the motor is controlled. A direct current (DC) voltage source is utilized for generating voltage pulses of fixed frequency and controlled duty ratio so as to form input voltage pulses to the static contactor. The angular position of the rotor is determined by an angle position sensor. The determined information is delivered. Independent claims are also included for the following: (1) an integrated electromechanical brake actuator comprising a linearly-movable pusher mechanically connected to a motor (2) an aircraft undercarriage comprising an integrated electromechanical brake actuator and an axle.