Three-Phase Machine Heating Mode for Cold Hydraulic Pump Startup
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Solution Overview
Problem
Existing electric motor designs face a trade-off between efficient warm-up and minimal post-warm-up losses, with conventional methods either underutilizing ohmic losses for heating or overcomplicating rotor laminations to minimize friction.
Innovation Solution
A three-phase machine with a control device that selectively energizes coils with alternating currents, allowing for an operating mode with torque generation and a heating mode with increased power loss through rapid polarity changes, utilizing hysteresis losses for efficient heating and reducing viscosity of hydraulic fluid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the internal resistance of coils is kept low to reduce continuous heating and improve motor efficiency, then the positive effect of ohmic losses during self-heating at low temperatures is reduced
Solution Approach 1:
The patent applies dynamics by enabling the motor to switch between two distinct operational states: a first operating mode with low internal resistance for efficient continuous operation, and a second operating mode with high internal resistance for rapid warm-up. The control device dynamically adjusts the coil configuration based on temperature requirements, allowing the motor to optimize its electrical characteristics for the current operational need without being constrained by a fixed resistance value
Solution Approach 2:
The patent implements parameter changes by modifying the electrical resistance parameter of the coils through reconfigurable connections. The control device can alter the effective internal resistance by switching between different coil winding configurations (e.g., series/parallel arrangements), thereby changing the motor's electrical parameters to match the desired operational state—low resistance for efficiency, high resistance for heating
2Reliability
If the rotor surface is designed to minimize friction with the fluid to ensure functionality at cold temperatures, then more complex tooling for the rotor laminations is required
Solution Approach 1:
The patent replaces the mechanical approach of minimizing friction through complex rotor surface design with an electrical/thermal approach. Instead of modifying the mechanical structure of the rotor to reduce friction, the system uses controlled heating of the hydraulic fluid to reduce its viscosity, thereby reducing friction forces. This substitution eliminates the need for complex rotor tooling while achieving the same reliability goal
Solution Approach 2:
The patent applies preliminary action by heating the hydraulic fluid before the motor begins its normal operating cycle. The control device activates the heating mode in advance, warming the fluid to reduce its viscosity and friction properties before the motor requires full operational capability. This preliminary thermal preparation ensures reliable motor function at cold temperatures without requiring complex mechanical modifications
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 friction and viscosity, while maintaining efficient torque generation, and avoids complex rotor lamination designs, thus improving motor efficiency and reducing production costs.
Implementation Method 1
heating function for electric motors using iron or hysteresis losses and/or ohmic losses when exciting the coils in the electric motor
Implementation Method 2
The self-heating of electric motors is primarily caused by ohmic losses in the copper components (e.g., coils, cage, etc.)
Implementation Method 3
The magnetic fields generated by the coils superimpose to form a rotating magnetic field, which drives the rotation of the rotor
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A three-phase machine is disclosed which runs at least partially in a fluid and has a stator (110) with at least three coils (111, 112, 123) and a rotor (120) with at least one magnet (125). The rotor (120) is surrounded by the at least three coils (111, 112, 123) in a cross-sectional plane perpendicular to its axis of rotation (R). The three-phase machine includes a control device (130) configured to selectively energize the three coils (111, 112, 113) with three alternating currents; to initiate a working mode (132) in which three alternating currents generate a torque on the rotor (120) about the axis of rotation (R); and to initiate a heating mode (134) in which the three alternating currents generate increased power loss compared to the working mode (132) due to a faster polarity reversal in at least one of the three alternating currents.