Magnetic Check Valve Control via Pump Torque Estimation
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Solution Overview
Problem
Conventional hydraulic systems for household appliances, such as washing machines and dishwashers, face challenges in efficiently controlling magnetic check valves without additional sensors, as they require higher pressure to open the flap and may not detect flap position accurately, leading to potential oversizing of pumps and increased costs.
Innovation Solution
A hydraulic system with a magnetic check valve and a control unit that estimates the motor torque from current consumption and voltage to determine the flap position, allowing for closed-loop control of the pump motor and optimizing operation by adjusting speed to overcome magnetic forces, thereby ensuring proper system operation without additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a magnetic check valve is used to ensure unidirectional flow, then flow control reliability is improved, but the pressure required to open the flap increases
Solution Approach 1:
The control unit monitors motor current consumption and voltage to estimate torque, using this feedback to determine flap position. This allows the system to adapt to the higher opening pressure requirement by dynamically adjusting motor operation based on actual load conditions.
Solution Approach 2:
The system changes operational parameters (motor speed, voltage, current) to overcome the magnetic retention force. By adjusting these parameters dynamically, the system can generate sufficient opening pressure when needed while maintaining efficient operation during normal flow.
2Measurement precision
If additional sensors are added to detect flap position, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The motor's own electrical parameters (current, voltage) are used to infer flap position, eliminating the need for separate sensing components. The motor effectively serves its primary function while also providing position detection information through its electrical characteristics.
Solution Approach 2:
The control unit acts as an intermediary that processes motor electrical parameters to determine flap position. Instead of directly sensing mechanical position, the system uses electrical measurements as intermediaries to infer the mechanical state.
3Power
If pump size is increased to overcome magnetic force, then power is improved, but energy consumption increases
Solution Approach 1:
The motor operates dynamically, adjusting speed and power output based on real-time feedback from electrical parameter monitoring. The motor delivers high power only when needed to open the flap, then operates at lower power during normal flow, optimizing energy efficiency.
Solution Approach 2:
The high-power operation occurs periodically only during flap opening events, rather than continuously. The motor alternates between high-power startup phase and lower-power normal operation, reducing overall energy consumption.
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 efficient detection of the check valve flap position without additional sensors, optimizing pump operation and reducing the need for oversized motors, thus enhancing system performance and cost-effectiveness.
Implementation Method 1
a magnetic check valve which, in order to allow flow passage in a direction of passage, must overcome a magnetic force which retains the flap in the closed position
Implementation Method 2
said torque of the motor being estimated from the current consumption of the motor and/or the voltage in the terminals of the motor
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Hydraulic system for a household appliance, said hydraulic system (1) comprising a pump comprising a BLDC-, BLAC-, or PMSM-type motor, an outlet conduit (3) connected to the outlet of said pump, a magnetic check valve (4) comprising a flap (40) and a control unit. The control unit is configured to control the speed of the motor in a closed loop and to determine whether the flap (40) of the check valve (4) is in the open position or in the closed position based on the torque of the motor estimated from the current consumption of the motor and/or the voltage in the terminals of the motor.