Electric Drive Flux Alignment for Full Current Testing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrical drive systems face challenges in testing their drive circuits at full rated current without actuating mechanisms that would be activated during normal use, particularly in applications where mechanical constraints prevent the use of full-rated current, such as in missile fin systems with pyrotechnic locking mechanisms.
Innovation Solution
The method involves aligning stator and rotor fluxes to allow current flow in the armature without inducing torque, using field-oriented control (FOC) techniques to control direct-axis and quadrature-axis currents, enabling the electrical drive system to carry full rated current while producing little to no torque, thereby facilitating comprehensive testing without mechanical activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If full rated current is applied to test the electrical drive system, then the drive circuits can be verified to be functioning correctly, but torque is generated that actuates the mechanical mechanism (e.g., shearing the shear-pin or triggering the pyrotechnic lock)
Solution Approach 1:
The patent changes the operational parameters of the electrical drive system by controlling the motor to operate in a flux alignment mode where the stator and rotor fluxes are aligned, rather than in normal torque-producing operation. This parameter change allows full rated current to flow through the armature while producing minimal or zero torque, enabling comprehensive testing of drive circuits at full load without actuating the mechanical mechanism
Solution Approach 2:
The patent employs dynamic control of the motor operation through field-oriented control (FOC) techniques, continuously adjusting the direct-axis and quadrature-axis currents to maintain flux alignment while allowing full current flow. This dynamic control enables the system to operate in a special testing mode that decouples current magnitude from torque production
2Reliability
If a pyrotechnic locking mechanism is used to withstand full-rated current testing, then the motor can be tested at full current, but the system becomes more complex and costly compared to a simple shear-pin design
Solution Approach 1:
The patent replaces the need for a robust mechanical locking mechanism (pyrotechnic lock) with an electrical control solution. By using field-oriented control to align fluxes and eliminate torque production during testing, the system allows the use of a simple shear-pin design without requiring the mechanical strength and complexity of a pyrotechnic locking mechanism, thereby reducing device complexity and cost while maintaining full testing capability
3Ease of manufacture
If current is reduced to avoid shearing the shear-pin, then the mechanism remains intact, but the testing capability is limited and cannot verify full-rated current operation
Solution Approach 1:
The patent changes the operational parameters of the motor by controlling flux alignment between stator and rotor, which decouples the relationship between current magnitude and torque production. This allows the system to maintain full rated current for comprehensive testing while keeping the shear-pin intact, as the aligned flux configuration produces minimal or zero torque despite full current flow
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 approach allows for the verification of electrical drive systems' ability to supply full rated current without generating undesirable torque, enhancing testing capabilities and reducing the need for costly pyrotechnic locks, while ensuring reliable operation and cost-effective maintenance.
Implementation Method 1
The fluxes may be aligned by controlling a current flowing in the armature windings
Implementation Method 2
Aligning the stator flux with the rotor flux enables current to flow in the armature without inducing torque on the rotor
Data Source
Figure 1~3
Figure 2
AI summary
In a method of operating an electrical drive system (10) that includes an electric motor (70), the electric motor (70) comprises an armature, which is mounted on a stator, and a rotor. Aligning the stator flux with the rotor flux enables current to flow in the armature without inducing torque on the rotor shaft (80). The method may be used, for example, in testing the electrical drive system (10). The electric drive system (10) can carry full rated current yet produce little or no torque, thereby increasing the current that can be tested during electrical drive test procedures, compared with prior-art procedures, without producing undesired forces or motion. The method may be used, for example, in heating the electric motor (70), for example for the purpose of de- icing. Again, the invention may enable the electric drive system (10) to carry full rated current yet produce little or no torque, thereby allowing the current to be used to generate heat in the motor (70).