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, which affects efficient operation and increases manufacturing costs.
Innovation Solution
A motor driving apparatus that includes an inverter controller, output current detection unit, and an output voltage detection unit with resistors and a comparator, allowing for efficient detection of motor voltage and estimation of rotor position without a position sensor, enabling accurate control of the motor in a sensorless mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a position sensor is installed to accurately detect rotor position, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The motor system uses its own operating characteristics (current, voltage, frequency) to estimate rotor position without external sensors. The controller performs self-diagnosis by analyzing the relationship between applied voltage and resulting current to determine rotor position, eliminating the need for separate position sensing components.
Solution Approach 2:
The patent replaces the mechanical/electrical position sensor system with an electronic estimation algorithm. By substituting physical sensing hardware with computational methods that analyze electrical parameters, the system achieves position detection without additional sensors, reducing device complexity while maintaining measurement capability.
2Ease of manufacture
If a position sensor is removed to reduce manufacturing cost, then ease of manufacture is improved, but measurement precision deteriorates
Solution Approach 1:
The system creates a virtual model of rotor position by estimating it from electrical parameters rather than directly measuring it. This computational copy of the position information allows the system to operate without physical sensors, reducing manufacturing cost while maintaining the functional equivalent of precise position detection.
Solution Approach 2:
The patent introduces electrical parameters (current and voltage) as intermediary variables to infer rotor position. Instead of directly measuring position, the system uses these intermediate electrical measurements combined with estimation algorithms to derive position information, achieving the same goal through a different measurement pathway.
3Device complexity
If voltage detection is simplified without additional sensors, then device complexity is reduced, but measurement precision of applied voltage deteriorates
Solution Approach 1:
The system uses feedback from current detection and knowledge of the applied voltage frequency to estimate the actual voltage. By continuously monitoring current response and comparing it with expected values based on applied voltage parameters, the controller can accurately determine the actual voltage being applied to the motor without direct voltage sensing.
Solution Approach 2:
The current detection unit serves multiple functions: it detects both the magnitude and phase of motor current, which are then used for both torque control and voltage estimation. This multi-functional use of the same sensor eliminates the need for separate voltage sensors, reducing device complexity while maintaining measurement precision through sophisticated signal processing.
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 motor voltage and estimation of rotor position, allowing for efficient control of the motor in a sensorless mode, reducing manufacturing costs and improving operational efficiency.
Implementation Method 1
an output voltage detection unit which detects output voltage applied to the motor in a PWM form by using a resistor and a comparator
Data Source
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AI summary
A motor driving apparatus and a laundry treatment machine including the same are disclosed. The laundry treatment machine includes a washing tub, a motor to rotate the washing tub, and a driving unit to drive the motor, wherein the driving unit includes an inverter to convert direct current (DC) voltage into alternating current (AC) voltage and to output the AC voltage to the motor, 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 and wherein the output voltage detection unit includes a resistor electrically connected between the inverter and the motor and a comparator to compare voltage detected by the resistor with reference voltage and to detect pulse width modulation (PWM)-based output voltage. In a sensorless laundry treatment machine which does not have a position sensor to sense the rotor position of the motor, therefore, it is possible to efficiently detect voltage applied to the motor.