Motor driving apparatus and laundry treatment machine including the same
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Solution Overview
Problem
Laundry treatment machines without position sensors face challenges in accurately estimating the rotor position of motors, leading to inefficiencies in motor control and operation.
Innovation Solution
A motor driving apparatus with an output voltage detection unit using resistors and a comparator to directly detect PWM-based pulse type output voltage, allowing the inverter controller to estimate rotor position and speed without additional signal conversion, enabling efficient sensorless motor control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a position sensor is installed to accurately sense rotor position, then measurement precision of rotor position is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the position sensing function from a dedicated position sensor and implements it using existing inverter components (switching devices and detection circuits) that are already present in the motor driving apparatus. This eliminates the need for separate position sensors while maintaining accurate rotor position detection capability.
Solution Approach 2:
The patent makes the inverter's switching devices and detection circuits serve dual functions: both motor control switching and rotor position sensing. By utilizing the existing inverter components for both purposes, the system achieves position detection without adding dedicated position sensing hardware, thereby reducing overall device complexity.
2Measurement precision
If signal conversion and additional processing circuits are added to detect output voltage, then measurement precision of output voltage is improved, but device complexity increases
Solution Approach 1:
The patent enables the inverter's own detection circuits to directly detect the output voltage applied to the motor without requiring external voltage sensing components. The system uses its existing detection infrastructure to serve the additional function of output voltage measurement, eliminating the need for separate voltage sensing hardware and signal conversion circuits.
Solution Approach 2:
The patent combines the output voltage detection function with the existing inverter detection circuits. By merging these functions into a single integrated detection system, the patent achieves accurate output voltage detection while avoiding the complexity of separate voltage sensing and signal conversion circuits.
3Productivity
If PWM-based pulse type output voltage is directly detected without signal conversion, then productivity and response speed are improved, but measurement precision may deteriorate
Solution Approach 1:
The patent performs preliminary processing of the PWM signal within the inverter's switching devices before detection, shaping the voltage waveform in a way that can be directly measured by the detection circuits. This preliminary action within the inverter eliminates the need for subsequent signal conversion while maintaining measurement accuracy.
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 enables accurate detection of output voltage and estimation of rotor position, improving motor control performance and efficiency in sensorless laundry treatment machines by eliminating the need for additional signal processing and enhancing operational reliability.
Implementation Method 1
a comparator to compare voltage detected by one of the resistors with reference voltage to detect PWM-based pulse type output voltage
Implementation Method 2
an inverter to convert direct current (DC) voltage into alternating current (AC) voltage and to output the AC voltage to the motor
Implementation Method 3
a motor to rotate the washing tub, and a driving unit to drive the motor
Data Source
AI summary
The laundry treatment machine; absent a position sensor to sense a rotor position, includes a driving unit having a DC/AC inverter, an output voltage detection unit to detect output voltage applied to the motor, and an inverter controller to control the inverter to drive the motor based on the output voltage. The output voltage detection unit includes a plurality of resistors electrically connected between the inverter and the motor and a comparator to compare voltage detected by some of the resistors with reference voltage and to detect pulse width modulation (PWM)-based output voltage. Based on the PWM-based output voltage at least one switching device of the inverter is turned on. The output voltage detection unit outputs voltage detected by other some of the resistors to the inverter controller in a second mode in which all switching devices of the inverter are turned off.