A method for controlling an asynchronous motor of a laundry treating machine and a laundry treating machine
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Solution Overview
Problem
Asynchronous motors in laundry treating machines can stall when operating at lower power supply voltages, especially when loaded with wet laundry, due to inadequate torque control, leading to inefficiencies and increased energy consumption.
Innovation Solution
A method for controlling an asynchronous motor in a laundry treating machine by using a switch to modify the capacity between a main coil and an auxiliary coil based on detected parameters such as voltage, current, phase, or rotation speed, with defined threshold values and time intervals to adjust the torque dynamically, and considering additional parameters like humidity or temperature for precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the second capacitor is switched on to support motor start and increase torque, then the motor can start reliably and operate at lower voltages, but energy consumption increases because the capacitor remains on too long
Solution Approach 1:
The patent applies feedback control by monitoring the actual motor current and comparing it against threshold values to dynamically control the switchable capacitor. The controller continuously adjusts the capacitor connection state based on real-time current feedback, ensuring the capacitor is connected only when needed for torque support and disconnected when the motor operates normally, thus preventing unnecessary energy consumption while maintaining reliable startup.
Solution Approach 2:
The patent implements dynamic control of the capacitor connection state based on varying motor operating conditions. Instead of a fixed time-based control, the system dynamically adjusts the capacitor switching decision based on real-time current measurements, allowing the motor to adapt to changing load conditions and voltage levels, optimizing both reliability and energy efficiency across different operating scenarios.
2Device complexity
If time-based control is used to switch the second capacitor, then the control is simple, but the control is too rough and supplies increased torque even when not required, increasing energy consumption
Solution Approach 1:
The patent replaces simple time-based control with feedback-based control that monitors motor current in real-time. The controller uses current threshold comparisons to make intelligent switching decisions, connecting the capacitor only when the motor current indicates insufficient torque availability. This feedback mechanism eliminates the 'rough' nature of time-based control while maintaining relatively simple circuitry, optimizing energy consumption without excessive complexity.
3Adaptability or versatility
If the motor operates at lower power supply voltages, then the machine can operate during voltage dips, but the motor may accidentally stall when loaded with wet laundry
Solution Approach 1:
The patent uses feedback control by continuously monitoring motor current to detect conditions that precede stalling. When the current exceeds predetermined thresholds, indicating the motor is struggling under load at reduced voltage, the controller automatically connects the switchable capacitor to provide additional torque. This real-time feedback mechanism allows the motor to adapt to voltage dips while preventing stalling under heavy load conditions.
Solution Approach 2:
The patent changes the electrical parameters of the motor system by introducing a switchable capacitor that alters the phase relationship between currents in the main and auxiliary windings. This parameter change increases the motor's torque capability at lower voltages, enabling the motor to maintain operation during voltage dips and prevent stalling without requiring changes to the external power supply.
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 ensures safe torque increase in critical situations, preventing motor stalling and optimizing energy efficiency by dynamically adjusting the motor's operation based on real-time conditions, thereby reducing the likelihood of stalling and overall energy consumption.
Implementation Method 1
a permanent first capacitor and a switchable second capacitor acting as phasing capacitors are interconnected between a main coil and an auxiliary coil of the motor
Implementation Method 2
an asynchronous motor includes a main coil and an auxiliary coil permanently interconnected via a first capacitor and switchably interconnected via a second capacitor
Data Source
Figure 1~3
Figure 4
AI summary
The present invention relates to a method for controlling an asynchronous motor (10) of a laundry treating machine, as well as to a laundry treating machine having an asynchronous motor (10) comprising a main coil (12) and an auxiliary coil (14) permanently interconnected via a first capacitor (22) and switchably interconnected via a second capacitor (24) by means of a switch (26), the laundry treating machine further comprises a control unit which detects the value of a first parameter of the asynchronous motor (10), and controls the ON and/or OFF state of the switch (26) on the basis of said value.