A Hybrid-Excited Resolver for High-Speed Operation

Accurate rotor position detection is essential for high-speed machine control systems, yet stable rotor position sensors for operations exceeding 30 krpm are lacking. While resolvers are renowned for their structure robustness in high-speed applications, the necessity for high-frequency enveloping during decoding leads to significant measurement errors as speeds increase, thereby restricting their applications in high-speed scenarios. This letter introduces a novel hybrid-excited resolver scheme designed to generate easily decodable signals for high-speed applications. The scheme employs conventional high-frequency voltage excitation at low speeds, and shifts to adjustable direct current excitation beyond a critical speed threshold, during which the resolver produces orthogonal output signals in the form of back-EMF with a consistent amplitude. By eliminating the need for high-frequency signal enveloping, this method enables the resolver to operate at ultra-high speeds without requiring complex structural modifications. Both simulations and experiments corroborate the effectiveness of this approach, validating its potential for practical applications.