Method of operating a variable speed motor in a laundry treatment apparatus
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Solution Overview
Problem
Laundry treatment apparatuses face challenges in managing heat generation during operation, particularly in confined spaces where inverter boards may overheat, especially in laundry dryers where ambient temperatures can exceed 60°C, leading to the need for effective heat dissipation solutions.
Innovation Solution
The method involves selecting a power supply modulation mode for variable speed motor units based on detected operation parameters, switching between continuous and discontinuous PWM modes to reduce heat generation and energy losses, thereby minimizing the need for heat sinks and improving energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If variable speed motor units are operated with continuous PWM modulation mode, then motor control precision and smooth operation are improved, but heat generation on the inverter board increases
Solution Approach 1:
The system dynamically switches between continuous PWM mode and discontinuous PWM mode based on operational conditions. The control unit monitors motor speed requirements and transitions between modulation modes to optimize the balance between control precision and heat generation, allowing the system to adapt its power supply characteristics in real-time
Solution Approach 2:
The invention changes the power supply modulation parameters by switching between continuous and discontinuous PWM modes. This parameter change allows the system to adjust the duty cycle and switching frequency characteristics, thereby controlling the heat generation level while maintaining adequate motor control performance under different operating conditions
2Temperature
If larger heat sinks are installed to dissipate heat from the inverter board, then heat dissipation capability is improved, but device complexity and space requirements increase
Solution Approach 1:
The invention converts the harmful effect of heat generation into a controllable parameter by using discontinuous PWM mode, which reduces switching frequency and thereby reduces heat generation. This approach transforms the thermal management problem from requiring passive heat dissipation (large heat sinks) to active heat reduction through modulation control
Solution Approach 2:
The invention replaces the mechanical/thermal solution (large heat sinks for passive heat dissipation) with an electrical/control solution (discontinuous PWM modulation to reduce heat generation at the source). This substitution eliminates the need for bulky thermal management components
3Loss of energy
If discontinuous PWM mode is used to reduce heat generation, then energy efficiency is improved, but motor control precision and operation smoothness deteriorate
Solution Approach 1:
The system dynamically selects between continuous and discontinuous PWM modes based on real-time operational requirements. During phases requiring high precision control, continuous mode is used; during phases where energy efficiency is prioritized or during steady-state operation, discontinuous mode is employed, creating a dynamic optimization strategy
Data Source
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AI summary
The invention relates to a method of operating a laundry treatment apparatus (2), in particular a washing machine, a laundry dryer, a heat pump laundry dryer or a washing machine having a drying function, wherein the apparatus comprises: a control unit (51) controlling the operation of the treatment apparatus, a laundry treatment chamber (18) for treating laundry (19), a detector unit for detecting at least one operation parameter (T_inv) of the treatment apparatus (2), and a first variable speed motor unit adapted at least to drive the treatment chamber, and/or a compressor (14) having a second variable speed motor unit for circulating a refrigerant fluid through a refrigerant loop of the laundry treatment apparatus (2), wherein the method comprises: selecting a predetermined power supply modulation mode for operating at least one of the first and second motor unit in dependency of the at least one detected operation parameter (T_inv), operating at least one of the first and second motor units in an operating cycle by applying or executing the selected predetermined power supply modulation mode.