Motor Switching Control Using Ripple-Adaptive MCU-FPGA Processing
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Solution Overview
Problem
Existing motor control technologies face limitations in performing high-speed switching operations due to increased ripple voltage and computational processing constraints, leading to inefficiencies, usability issues, and reliability concerns in motor control for compressors.
Innovation Solution
A motor control device and method that utilizes multiple computational processing elements to measure and adjust switching frequencies based on ripple voltage, allowing for efficient high-speed switching by selectively using a microcontroller unit (MCU) for low-speed operations and a field-programmable gate array (FPGA) for high-speed operations, thereby controlling the switching unit to limit ripple voltage and optimize switching operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-speed switching operation is performed, then motor control efficiency is improved, but ripple voltage of the DC link capacitor increases
Solution Approach 1:
The patent implements dynamic switching frequency adjustment by measuring the ripple voltage of the DC link capacitor in real-time and adaptively changing the switching frequency of the inverter. When ripple voltage exceeds a threshold, the switching frequency is reduced; when it is within acceptable ranges, the frequency is increased. This dynamic adaptation resolves the contradiction by allowing high-speed switching for efficiency while preventing excessive ripple voltage through automatic frequency modulation.
2Speed
If high-speed switching control is implemented, then motor operation performance is improved, but computational processing burden increases
Solution Approach 1:
The patent segments the computational processing tasks by separating ripple voltage measurement and switching frequency determination into distinct processing steps. The system measures ripple voltage, compares it against thresholds, and adjusts switching frequency in discrete computational cycles. This segmentation reduces the computational burden by breaking down the complex high-speed switching control into manageable, sequential operations that can be executed efficiently by the control device.
3Speed
If switching frequency is increased, then motor response speed is improved, but input current harmonic increases
Solution Approach 1:
The patent employs feedback control by continuously measuring the ripple voltage (which reflects input current harmonic content) and using this measurement to adjust the switching frequency. When ripple voltage indicates high harmonic content, the system reduces switching frequency to mitigate the harmonic distortion. This feedback mechanism resolves the contradiction by maintaining high response speed when harmonics are low while reducing frequency when harmonics increase, optimizing both performance and power quality.
Data Source
AI summary
The present specification relates to a motor control device, a motor control system, and a motor control method. The motor control device measures a ripple voltage of a DC link capacitor to determine an appropriate switching frequency according to the ripple voltage, and causes a plurality of arithmetic processing units to selectively control a switching operation of the switching unit according to the determined switching frequency.