Three-Phase Machine Heating Mode for Low-Temperature Hydraulic Fluid
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing motor designs face a challenge in balancing efficient heating of hydraulic fluid at low temperatures while minimizing ohmic losses to maintain efficiency and avoid overheating.
Innovation Solution
A three-phase machine with a control device that selectively energizes coils with alternating currents, allowing for a working mode to generate torque and a heating mode to increase power loss through rapid polarity changes, utilizing hysteresis losses to heat the fluid efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the internal resistance of coils is kept low to reduce ohmic losses and improve efficiency, then energy efficiency is improved, but the heating capability at low temperatures deteriorates
Solution Approach 1:
The control device alternates between working mode and heating mode. In heating mode, the polarity of alternating currents is changed more rapidly than in working mode, generating increased power loss through hysteresis losses in the motor lamination. This periodic switching allows the system to heat the hydraulic fluid when needed while maintaining low ohmic losses during normal operation.
Solution Approach 2:
The control device changes the operating parameters of the alternating currents by increasing the switching frequency or edge steepness during heating mode compared to working mode. This parameter change increases the hysteresis losses in the motor lamination, converting electrical energy to thermal energy for heating the hydraulic fluid without requiring high internal resistance in the coils.
2Productivity
If rapid polarity change is implemented to increase heating efficiency, then heating speed is improved, but power loss increases
Solution Approach 1:
The control device converts the normally harmful hysteresis losses, which are typically minimized in motor design, into a beneficial heating effect. By operating in heating mode with rapid polarity changes, the system deliberately increases hysteresis losses in the motor lamination to generate heat for the hydraulic fluid, transforming what is usually considered energy waste into a useful thermal output.
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
The solution enables rapid heating of hydraulic fluid, reducing viscosity and torque requirements, while maintaining efficiency by controlling magnetic fields and polarity changes to minimize ohmic losses.
Implementation Method 1
utilizing hysteresis losses to heat the fluid efficiently
Implementation Method 2
The self-heating of e-motors is primarily brought about by the ohmic losses in the copper parts
Implementation Method 3
The magnetic fields generated by the coils are superimposed to form a rotating magnetic field, which drives the rotational movement of the rotor
Data Source
AI summary
A three-phase machine is disclosed, which runs at least partially in a fluid and has a stator with at least three coils and a rotor with at least one magnet. The rotor is enclosed by the at least three coils in a cross-sectional plane perpendicular to its axis of rotation. The three-phase machine includes a control device, which is configured to energize the three coils selectively with three alternating currents; to initiate a working mode, in which three alternating currents generate a torque on the rotor about the axis of rotation; and to initiate a heating mode, in which the three alternating currents generate an increased power loss in comparison with the working mode due to a more rapid polarity change in at least one of the three alternating currents.