Sensorless Motor Control Using Rotor Stop Position for Fast Startup
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Solution Overview
Problem
Existing motor control methods require expensive sensors and complex wiring for accurate rotor position detection, leading to increased waiting times and reduced net acting ratios, especially when starting a motor with high inertia loads, causing user dissatisfaction.
Innovation Solution
A motor control apparatus and method that estimates the rotor position using a sensorless approach by applying a specific pattern of input signals to the motor and analyzing response signals, eliminating the need for separate position detection sensors and reducing alignment time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If sensorless control with direct current application is used to align rotor position, then manufacturing cost is reduced, but waiting time increases and net acting ratio decreases
Solution Approach 1:
The controller applies a specific pattern signal before the motor is driven to preliminarily align the rotor position. This preliminary action eliminates the need for waiting time during motor startup while maintaining sensorless control benefits, directly resolving the contradiction between reduced manufacturing cost and increased waiting time
Solution Approach 2:
The controller applies a periodic specific pattern signal (such as a sinusoidal or triangular wave) to the motor phases to generate rotating magnetic field that aligns the rotor position quickly. This periodic action enables rapid position alignment without requiring prolonged waiting time, thus improving net acting ratio while maintaining cost-effectiveness
2Ease of manufacture
If sensorless control with direct current application is used to align rotor position, then manufacturing cost is reduced, but net acting ratio decreases
Solution Approach 1:
The controller performs preliminary rotor position alignment by applying a specific pattern signal before motor operation begins. This ensures the motor starts from an optimized position, maximizing torque production from the very first moment of operation and thereby improving net acting ratio without sacrificing the cost benefits of sensorless control
Solution Approach 2:
The controller rapidly completes the rotor position alignment process by applying a high-frequency specific pattern signal, effectively skipping through the alignment phase in minimal time. This allows the motor to reach productive operation much faster, improving net acting ratio while maintaining the simplicity and low cost of sensorless control
3Measurement precision
If predetermined waiting time is applied for rotor position alignment, then rotor position accuracy is improved, but productivity decreases
Solution Approach 1:
The controller applies a periodic specific pattern signal (sinusoidal or triangular wave) that rapidly generates a rotating magnetic field to align the rotor position with high precision. This periodic action achieves accurate position detection in minimal time, eliminating the need for prolonged waiting periods while maintaining high rotor position accuracy
Solution Approach 2:
The controller changes the signal parameters (frequency, amplitude, pattern) dynamically during the alignment process. By applying a high-frequency specific pattern signal initially for rapid alignment, then transitioning to normal operation parameters, the system achieves both high position accuracy and fast response, improving productivity without sacrificing precision
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 approach reduces manufacturing costs, minimizes motor movement during operation, and improves the net acting ratio by accurately estimating the motor position quickly, even with high inertia loads, providing faster operation and reduced user wait times.
Implementation Method 1
applying a specific pattern input signal to a motor and checking a response signal according to the applied input signal
Implementation Method 2
a motor may be driven by applying an input signal of a specific pattern
Data Source
AI summary
Disclosed is a motor control apparatus including an inverter part configured to convert DC power into AC power and provide the AC power to a motor, and a controller configured to control driving of the motor by using the inverter part, the controller configured to identify a stop position of a rotor in previous driving of the motor, and control the inverter part to apply an input signal of a specific pattern to the motor according to a start of driving the motor, wherein a phase of the input signal of the specific pattern is determined on the basis of the stop position of the rotor. Other example embodiments may be provided.