Induction Motor Controller Conduction Angle Modulation
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Solution Overview
Problem
Existing motor control systems struggle to tailor electrical power to achieve specific speed, direction, or torque in induction motors when the incoming power has a fixed frequency and waveform, such as 60 Hz, which does not match the desired operational parameters.
Innovation Solution
A motor control technique that includes a controller configured to receive AC power and selectively transmit it during a sinusoidal conduction angle, using solid-state switches to generate output power at a frequency and waveform tailored to the desired motor operation by applying sinusoidal reference values to adjust the conduction angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If AC power with fixed frequency (e.g., 60 Hz) is directly applied to the motor, then the system is simple, but the motor cannot achieve desired speed, direction, or torque control
Solution Approach 1:
The patent applies periodic action by using sinusoidal reference values to periodically switch solid-state switches during AC power cycles. The conduction angle is modulated sinusoidally at a lower frequency than the AC power, creating a controlled output waveform that enables motor speed and torque control while maintaining system simplicity
Solution Approach 2:
The patent changes parameters by varying the conduction angle of the solid-state switches based on sinusoidal reference values. This parameter modulation transforms the fixed-frequency AC input into a controlled output with adjustable frequency and amplitude characteristics, enabling precise motor control without complex conversion circuits
2Measurement precision
If complex components like IGBTs and rectifiers are used to convert AC power frequency, then precise motor control is achieved, but system cost and complexity increase
Solution Approach 1:
The patent extracts only the essential switching function needed for control, using simple solid-state switches instead of complex IGBT modules. By removing unnecessary conversion stages and keeping only the critical conduction angle modulation, the system achieves precise control with reduced component complexity and cost
Solution Approach 2:
The patent employs inexpensive solid-state switches rather than expensive IGBTs and rectifier assemblies. These simpler components achieve the required control precision through clever switching strategies based on sinusoidal reference values, reducing overall system cost while maintaining performance
Data Source
AI summary
Systems, methods, and devices are disclosed, including an induction-motor controller that has a motor controller configured to receive alternating current (AC) power with a voltage that varies generally sinusoidally and transmit the AC power during a conduction angle of a cycle of the AC power. In some embodiments, the conduction angle varies generally sinusoidally at a lower frequency than the AC power, and the motor controller may be configured to not transmit the AC power outside of the conduction angle.