Sharif Digital Repository

Resolvers, due to their robust structure, are widely used in automation systems. Among the types of resolvers, the accuracy of the Wound Rotor (WR) resolver in the occurrence of common mechanical errors is higher than other types of resolvers. therefore, in this thesis, an AFWRR is studied to improve the performance. Increasing the number of poles in WR resolvers is a good solution for increasing the accuracy of these electromagnetic position sensors. However, high-speed WR resolvers due to employing fractional slot windings suffer from rich sub-harmonics in the induced voltages. A common solution for suppressing the undesirable sub-harmonics is using multi-layer winding with appropriate... 

Today, position sensors are inseparable parts of engineering systems. Encoders and resolvers are the most common types of position sensors that are widely used in industries. Due to low price and high accuracy, encoders are the first choice of engineers. Yet, their performance deteriorates under harsh conditions, namely wide temperature range operation, intense vibration and polluted environments. On the contrary, resolvers are rigid and robust which make them resistant to polluted environments.According to principle of operation, resolvers are divided to two main types: variable reluctance (VR) and wound-rotor (WR). Researches has shown that wound rotor resolvers have better performance... 

Resolver is the recommended position sensor in harsh environments where there is wide temperature variation, vibration, and dust. Resolvers are divided into two groups: Wound-Rotor (WR) resolvers and Variable Reluctance (VR) ones. The most commercial resolvers are WR resolvers that they have 2-phase, orthogonal, signal windings on their stator and a single-phase excitation winding on their rotor. Due to the electromechanical structure of the resolver, the mechanical and electrical faults of electrical machines are expected in resolvers. Therefore, in this dissertation, the effect of mentioned faults in WR resolvers was investigated.In this dissertation, a non-invasive method with the help of... 

Position sensors are an inevitable part of motion control mechanisms with inverter-driven electric machines. Encoders and resolvers are two common types of position sensors. Resolvers are preferred over encoders due to their superior performance in polluted and noisy environments with wide temperature variation or high vibration. Conventional resolvers are synchronous generators whose excitation winding is fed by an AC instead of a DC voltage. There are different types of resolvers for determining position in linear or rotational motions. However, increasing usage of two-degree of freedom (2-DOF) motors for simultaneous rotational and linear motion leads to request for helical motion... 

The need for position sensors has increased substantially with the development of electric vehicle motion control systems. In industrial applications, encoders are commonly used for positioning, but in polluted industrial environments, with large temperature variation and vibration, the resolver is preferred to optical encoder. Resolver is a two-phase synchronous generator with a high frequency AC excitation voltage instead of DC voltage. Therefore, the output voltages of the resolver are amplitude modulated (AM) voltages which in order to determine the output position, it is necessary to extract the envelope of these signals using R/D converter. In envelope extraction methods, to ensure... 

Providing a precise estimation of the position of a moving element is one of the requirements of many position control systems. Resolvers, as electromagnetic sensors, are one of the most suitable options for use in harsh environments with high thermal and mechanical stresses and high contamination. Although resolvers are the most reliable solution for sensitive applications in stressful environments, they are less accurate in normal operating conditions than optical encoders. In this regard, many efforts have been made to reduce the estimated position. Most of the studies have focused on modifying the electronic converter structure, which is responsible for processing the output signals of... 

The need for position sensors has increased substantially with the development of electric vehicle motion control systems. In industrial applications, encoders are commonly used for positioning, but in polluted industrial environments, with large temperature variation and vibration, the resolver is preferred to optical encoder. Resolver is a two-phase synchronous generator with a high frequency AC excitation voltage instead of DC voltage. Therefore, the output voltages of the resolver are amplitude modulated (AM) voltages which in order to determine the output position, it is necessary to extract the envelope of these signals using R/D converter. In envelope extraction methods, to ensure...