Synchronous Reluctance Pump Motor for Industrial Trucks
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Solution Overview
Problem
Industrial trucks with battery-powered hydraulics face inefficiencies and high maintenance costs due to the use of DC machines, which are less efficient and more complex than AC machines, and require frequent maintenance of sliding contacts, while AC machines require complex control systems for three-phase rotating fields.
Innovation Solution
An industrial truck with a synchronous reluctance machine as the electric pump motor, featuring a stator with three-phase windings and a rotor of soft magnetic material with low magnetic reluctance, excited by sinusoidal currents to generate a continuous rotating magnetic field, eliminating the need for magnets and reducing material costs, ohmic losses, and maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If DC machines are used as electric pump motor, then low cost is achieved, but efficiency is reduced and maintenance complexity increases
Solution Approach 1:
The patent replaces the mechanical commutator and brush system of DC machines with an AC motor design using sinusoidally excited stator windings. This substitution eliminates sliding contacts while maintaining simplicity, achieving both low cost and high efficiency by using standard AC power supply and eliminating energy losses associated with brush-commutator friction and electrical contact resistance.
Solution Approach 2:
The patent changes the electrical parameter from DC to AC with sinusoidal excitation. By using sinusoidally varying currents in the stator windings, the system achieves continuous rotating magnetic field generation without commutation, improving efficiency while keeping the motor structure simple and cost-effective for industrial truck applications.
2Ease of manufacture
If DC machines are used as electric pump motor, then low cost is achieved, but device complexity increases due to sliding contacts
Solution Approach 1:
The patent replaces the mechanical commutator and brush system of DC machines with an AC motor design using sinusoidally excited stator windings. This substitution eliminates sliding contacts while maintaining simplicity, achieving both low cost and high efficiency by using standard AC power supply and eliminating energy losses associated with brush-commutator friction and electrical contact resistance.
3Loss of energy
If AC machines are used as electric pump motor, then efficiency and simplicity are improved, but control complexity increases due to three-phase rotating field requirements
Solution Approach 1:
The patent changes the electrical parameter from DC to AC with sinusoidal excitation. By using sinusoidally varying currents in the stator windings, the system achieves continuous rotating magnetic field generation without commutation, improving efficiency while keeping the motor structure simple and cost-effective for industrial truck applications.
Solution Approach 2:
The patent applies universal AC motor principles to the hydraulic pump drive, using standard three-phase AC power supply and conventional sinusoidal excitation methods. This approach leverages well-established, simple control techniques that are widely available in industrial trucks, avoiding complex specialized control systems while achieving high efficiency.
4Ease of manufacture
If sliding contacts are used in DC machines, then low cost is achieved, but maintenance requirements increase due to wear
Solution Approach 1:
The patent replaces the mechanical commutator and brush system of DC machines with an AC motor design using sinusoidally excited stator windings. This substitution eliminates sliding contacts while maintaining simplicity, achieving both low cost and high efficiency by using standard AC power supply and eliminating energy losses associated with brush-commutator friction and electrical contact resistance.
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 provides a cost-effective, robust, and reliable pressure medium supply with reduced material usage, lower maintenance needs, and improved efficiency, allowing for easy adaptation to performance requirements and effective thermal management, while maintaining high operational reliability and simplicity in assembly.
Implementation Method 1
the turning movement is generated by a rotating magnetic field, which the rotor tries to follow
Implementation Method 2
torque is generated in a reluctance machine due to the action on a soft magnetic material of a rotor Maxwell's force acting in a magnetic field
Implementation Method 3
the rotor must have a preferred orientation within the magnetic field and therefore poles... the electric pump motor being designed as a synchronous reluctance machine
Data Source
Figure 1a~1c
Figure 2
Figure 3
AI summary
In a forklift truck with a working hydraulic system supplied with pressure medium by a hydraulic pump (33), wherein the hydraulic pump (33) is driven by an electric pump motor (32), the electric pump motor (32) has a stator with at least three phase windings for generating a rotating field and a rotor (1) with soft magnetic material of high permeability, wherein the rotor (1) has poles (5) with low magnetic reluctance in the orientation of the poles (5).