Sensorless Motor Control Using Patterned Voltage for Fast Startup
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Solution Overview
Problem
Existing sensorless motor control methods for washing machines require initial position alignment, which prolongs the startup time and reduces efficiency, especially with increased inertia of driven objects.
Innovation Solution
A motor control apparatus and method that estimates stator resistance and rotor position using a specific patterned input voltage, allowing for rapid motor startup without initial position alignment, utilizing an inverter to convert DC power to AC and control the motor based on response currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If initial position alignment is performed using related art sensorless control, then starting characteristics and detection performance are stabilized, but the time required for alignment increases and net acting ratio is lowered
Solution Approach 1:
The patent extracts the initial position alignment process from the motor startup sequence by using sensorless control to directly estimate rotor position and stator resistance. This eliminates the separate alignment step that traditionally required applying specific currents and waiting for stabilization, thereby reducing alignment time while maintaining reliable starting characteristics through accurate position estimation.
Solution Approach 2:
The patent performs preliminary estimation of rotor position and stator resistance using sensorless control methods before motor startup. By pre-calculating the initial position and resistance values through mathematical models and response current analysis, the system prepares all necessary parameters in advance, eliminating the need for time-consuming alignment procedures during actual startup.
2Measurement precision
If initial position alignment is performed, then detection performance is improved, but the structure and wirings become complicated
Solution Approach 1:
The patent implements self-service position detection by using the motor's own electrical characteristics (phase currents, voltages, and impedance) to estimate rotor position and stator resistance. The motor system detects its own state through sensorless control algorithms that analyze response currents during normal operation, eliminating the need for external encoders, resolvers, or hall sensors and their associated complex wirings.
Solution Approach 2:
The patent replaces mechanical position detection devices (encoders, resolvers, hall sensors) with an electrical-field-based sensorless control system. Instead of using mechanical or magnetic field sensors that require physical mounting and complex wiring, the system uses electrical impedance analysis and current response measurements to infer position information, thereby simplifying the overall device structure.
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 the time required for motor alignment, enhances startup efficiency, and minimizes noise and torque ripple, enabling faster motor operation and improved performance.
Implementation Method 1
an inverter part configured to convert direct current (DC) power into alternating current (AC) power and output the AC power to a motor
Implementation Method 2
a motor whose operation is controlled by the control apparatus
Data Source
AI summary
Disclosed is a motor control apparatus, a motor control system, and a motor control method that estimate a stator resistance and a rotor position for sensorless control of a motor.