Electric Pump Stator Heat Generation Control
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Solution Overview
Problem
Existing electric pumps face difficulties in driving the rotor at low liquid temperatures and high viscosity, as the liquid viscosity-induced drive resistance exceeds the rotational drive force, and adding a heater increases size and manufacturing costs.
Innovation Solution
An electric pump with a brushless electric motor and liquid pump combination, featuring a heat generation control mode that efficiently heats the stator coil to reduce viscosity, using a temperature detector and rotational speed controller to manage power application, without the need for a separate heater.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a separate heater is added to heat the liquid, then the liquid viscosity is reduced and the rotor can rotate, but the size of the electric pump increases and manufacturing costs increase
Solution Approach 1:
The heating function is merged with the stator coil of the electric motor. The stator coil serves dual purposes: generating electromagnetic force for motor operation and generating heat through resistive heating when electric power is applied. This eliminates the need for a separate heater, maintaining compact size and reducing manufacturing costs while still achieving the required liquid temperature increase to reduce viscosity
Solution Approach 2:
The stator coil is designed to perform multiple functions: it acts as both the electromagnetic component for motor rotation and as a heating element for viscosity reduction. By controlling the application of electric power to the stator coil, the system can switch between motor operation mode and heating mode, providing universal functionality without additional components
2Temperature
If electric power is applied to the stator coil for heating, then the liquid viscosity is reduced, but the heating efficiency must be optimized to avoid excessive energy consumption
Solution Approach 1:
The control device applies electric power to the stator coil in a periodic or intermittent manner rather than continuously. The system monitors the liquid temperature and applies power only when heating is required to maintain the liquid above the viscosity threshold. This periodic action reduces overall energy consumption while still achieving the necessary temperature maintenance
Solution Approach 2:
The control device adjusts the parameters of electric power application (voltage, current, duration) to the stator coil based on the liquid temperature and viscosity conditions. By optimizing these parameters, the system achieves efficient heating with minimal energy consumption, balancing the trade-off between heating effectiveness and energy usage
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
Enables efficient operation at low temperatures and high viscosity conditions without increasing the pump's size or manufacturing costs, by effectively reducing liquid viscosity through controlled heat generation.
Implementation Method 1
a heat generation control mode for controlling application of electric power to the stator such that the stator generates heat at a higher heating efficiency than the heating efficiency of the stator when the application of electric power is controlled in the normal mode
Implementation Method 2
a permanent magnet is provided to the rotor of the electric pump, and the rotor thereby rotates under electromagnetic force from the stator coil
Data Source
Figure 1
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Figure 3
AI summary
An electric oil pump (1) constructed by integrally combining an electric motor (2) with an oil pump (3), wherein: the electric motor is composed of a motor casing (10), a drive shaft (42) that is disposed in a motor housing chamber (12) formed inside the motor casing and is rotatably supported, a rotor (40) that is disposed on the drive shaft, and a stator (20) that is located inside the motor housing chamber and is attached to the motor casing; the electric oil pump is equipped with an internal controller (45) that controls application of electric power to the stator so as to cause the drive shaft to be driven to rotate via the rotor; and the internal controller is equipped with a normal mode for controlling application of electric power to the stator such that the drive shaft rotates in accordance with an externally input rotation command and a heat generation mode for controlling application of electric power to the stator such that the stator generates heat at a higher heating efficiency than the heating efficiency of the stator when the application of electric power is controlled in the normal mode.