Multiphase AC Electrostatic Machine for Full-Speed Torque
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Solution Overview
Problem
Conventional electrostatic machines face challenges due to the need for large drive voltages to generate electric fields, which can lead to material decomposition and increased manufacturing costs. Additionally, these machines often require complex and expensive circuits to generate the necessary voltages, and they may suffer from reduced torque at low speeds.
Innovation Solution
The proposed electrostatic machine system uses a multiphase AC drive voltage configuration, where both the rotor and stator are driven by alternating current. This system eliminates the need for large DC voltages, allows for full torque at any operating speed, and reduces manufacturing costs by simplifying the voltage generation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If large DC voltages are used to generate electric fields in conventional electrostatic machines, then sufficient torque can be produced, but material decomposition occurs and manufacturing costs increase
Solution Approach 1:
The patent applies periodic AC voltage instead of continuous DC voltage to generate electric fields. The alternating nature of AC voltage allows the electric field to reverse direction periodically, preventing continuous stress on dielectric materials and eliminating electrochemical decomposition reactions that occur with DC voltage, while still producing sufficient torque through cyclic field generation.
Solution Approach 2:
The patent changes the voltage parameter from DC to AC, fundamentally altering how the electric field is generated. This parameter change enables torque production through alternating field interaction with rotor-stator capacitance variations, avoiding the material decomposition issues inherent in high-voltage DC operation while maintaining effective power conversion.
2Use of energy by moving object
If large DC voltages are used in conventional electrostatic machines, then electric fields can be generated, but complex and expensive voltage generation circuits are required
Solution Approach 1:
The patent changes the voltage parameter from DC to AC, which fundamentally simplifies the voltage generation approach. AC voltage can be directly obtained from standard power sources or simple inverters, eliminating the need for complex high-voltage DC generation circuits, rectifiers, and voltage multipliers required in conventional electrostatic machines.
Solution Approach 2:
The patent replaces complex electrical circuitry for voltage generation with a simpler AC drive system. By using AC voltage applied to stator windings that generate rotating magnetic fields, the system eliminates the need for complex DC voltage generation and switching circuits, achieving voltage generation through electromagnetic induction instead of elaborate electronic circuitry.
3Speed
If conventional electrostatic machines operate at low speeds, then they can function, but torque is reduced
Solution Approach 1:
The patent uses periodic AC voltage applied to stator windings to generate rotating magnetic fields that interact with rotor magnets. This periodic field generation maintains consistent torque production across all speeds, including low speeds, because the rotating field continuously interacts with the rotor magnets regardless of rotor speed, eliminating the torque reduction problem at low operating speeds.
Solution Approach 2:
The patent replaces conventional electrostatic field generation with electromagnetic field generation using AC-driven stator windings and rotor magnets. This substitution enables full torque production at all speeds by utilizing magnetic field interaction rather than electrostatic field interaction, which is inherently speed-dependent in conventional designs.
4Power
If AC drive voltage is used in the electrostatic machine system, then full torque can be achieved at any operating speed, but the system requires multiphase voltage generation
Solution Approach 1:
The patent replaces electrostatic field generation with electromagnetic field generation using multiphase AC drive circuits. The multiphase AC voltage applied to stator windings generates rotating magnetic fields that provide consistent torque across all speeds. While multiphase generation is required, modern power electronics make this relatively simple compared to the high-voltage DC generation and switching circuitry needed in conventional electrostatic machines.
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 system achieves efficient torque production across a wide range of operating speeds using AC voltages, mitigates material degradation issues associated with DC operation, and lowers production costs through simplified voltage generation and reduced material requirements.
Implementation Method 1
When VR is applied to the first set of terminals and VS is applied to the second set of terminals, the rotor and the stator generate respective electric fields which, when properly aligned, cause the rotor to produce torque relative to the stator
Data Source
AI summary
In one or more arrangements, an electrostatic machine is presented that includes a rotor and a stator. The rotor has a first set of terminals configured to receive a first multiphase AC drive voltage (VR) and the stator has a second set of terminals configured to receive a second multiphase AC drive voltage (VS). When VR is applied to the first set of terminals and VS is applied to the second set of terminals, the rotor and the stator generate respective electric fields which, when properly aligned, cause the rotor to produce torque relative to the stator and induce rotational motion when sufficient torque is generated.