In response to the potential frequency secondary drop problem of direct-drive wind power systems in the scenario of continuous frequency drop faults in the power grid，the principle of primary frequency regulation of direct-drive wind power systems was analyzed. A primary frequency regulation control strategy for direct-drive wind power systems was proposed based on the product and difference combination of frequency change rates at pre- and post-sampling times. According to the established criteria，the droop coefficient of the direct-drive wind power system in different frequency response stages was adjusted by comprehensively considering the fan speed，frequency deviation，and frequency rate of convergence，to realize the active frequency support and flexible frequency modulation exit of the wind power system. A simulation model of a direct-drive wind power system was established in Matlab/Simulink to verify the effectiveness of the proposed control strategy.

In order to improve the accuracy and stability of short-term wind direction prediction，a wind direction prediction method based on lidar wind data and an improved nonlinear echo state network （NESN） model was proposed.First of all，wind direction data 100 meters ahead of the wind turbine was obtained by laser wind detection radar. Secondly，the multivariate polynomial function was used to construct the nonlinear relation of the internal state of the reserve pool，the order of the weight matrix and the complexity of model calculation were reduced.Finally，the prediction model was established and the simulation prediction was carried out on different lidar data sets.The results show that compared with the nonlinear echo state network and adaptive neuro fuzzy inference system （ANFIS），the mean absolute error （MAE），root mean square error （RMSE），normalized mean absolute error （NMAE）and normalized root mean square error （NRMSE）of the improved NESN model are significantly reduced，and the prediction accuracy and stability are improved.The accuracy of the wind turbine alignment the wind direction is improved and the mechanical loss of yaw is reduced.

With the continuous increase in the scale of distribution network construction and operation，a large number of electricity load control problems have emerged，especially the weakening of sample time series characteristics in electricity load data analysis，resulting in incomplete acquisition of local load characteristics，making it impossible for the distribution network electricity load prediction system to maintain the balance of energy in the power grid. In the past，the impact of "source-load" uncertainty was also rarely considered in the distribution network electricity load processing and distribution，which can easily lead to low probability of electricity load classification recognition，significant errors in electricity load prediction，and long-term problems such as high generation costs and insufficient distribution balance. In response to the above situation，the uncertainty of "source" and "load" was conducted research through probability distribution functions. A multi-objective function composed of two probability distribution functions was set as the constraint conditions for the coordinated output balance. The improved cluster eddy current search algorithm was used to solve the problem，and a coordinated control scheme for electricity load was obtained. The test results show that at 17：00，the power of photovoltaic device 1 is 1 050 kW， at 11：00，the power of photovoltaic device 2 is 980 kW，based on the source-load uncertainty root-mean-square error of less than 0.7%. The cost of the scheme based on "source-load" uncertainty is 453 200 yuan，and the balance degree is 0.94. The collaborative control method based on "source-load" uncertainty has a higher balance than the collaborative control method without "source-load" uncertainty，and the collaborative control technology is more reasonable.

Aiming at the problem of insufficient frequency modulation capability of direct-driven wind turbine under traditional virtual inertia control，a control strategy of super capacitor assists direct-driven wind turbine participating in frequency modulation was proposed to improve the frequency stability of power grid after wind power is connected. Firstly，the influence of the fan speed and output power on the frequency modulation capability when the direct-driven wind turbine participates in the frequency modulation through virtual inertia control is analyzed，and the frequency modulation coefficient was established through the Sigmoid function to characterize the frequency modulation capability of it under different operating conditions. Then，based on the frequency modulation coefficient，a frequency modulation strategy for wind storage was proposed，that is when the frequency modulation ability of direct-driven wind turbine is strong，the direct-driven wind turbine participates in the frequency modulation independently，while when the frequency modulation capability is weak，the power required for the frequency modulation is jointly provided by the direct-driven wind turbine and the super capacitor. At the same time，the charging and discharging coefficient was introduced into the power control of the super capacitor to avoid its over-charging and over-discharging. At last，the simulation results show that the proposed method is better than the traditional virtual inertia control when frequency modulation capability of the direct-driven wind turbine is insufficient，and it also avoids overcharging and discharging of super capacitor.

The traditional control of electromechanical actuator in aviation electromechanical servo system mostly adopts two-level inverter and PID control，which can not achieve higher precision control of permanent magnet synchronous motor. In view of the above problems and the difficulty of space vector modulation algorithm to solve the problem of neutral point voltage balance，a model predictive control method based on improved virtual space vector method was proposed，and the corresponding control strategy was designed. The model predictive control was used to improve the control response speed and control accuracy of the permanent magnet synchronous motor. The neutral point clamped（NPC） three-level inverter with more sinusoidal output was used. The improved virtual space vector pulse width modulation（VSVPWM） was used to construct a dodecagon virtual space vector diagram closer to the vector circle. The simulation results show that the improved method can realize the stable operation of permanent magnet synchronous motor under low torque ripple，and has a good control effect on the midpoint voltage balance problem.

Due to the advantages of faster dynamic performance and smaller torque ripple， high frequency pulse voltage injection （PSVI） is widely used in sensorless control of permanent magnet synchronous motor （PMSM） at low-speed range. Under low switching frequency， the dynamic and steady performance of the traditional high frequency pulse voltage injection method is seriously affected due to the larger system delay， the high-frequency phase update delay caused by the special control structure， and the increase of the phase delay caused by the lower cut-off frequency of the filter. In view of the above problems， compensation schemes for different non-ideal factors were proposed based on the detailed analysis of the influence of the filter phase delay and the delayed phase update of high frequency pulse voltage under low switching frequency on the rotor position estimation. Finally， the influence of the above non-ideal factors and the compensation scheme were simulated and verified. The simulation results show that the proposed solution can effectively reduce the rotor position estimation error.

During the joint operation of permanent magnet direct drive wind power generation systems，the changes in motor side parameters may cause problems such as reduce control accuracy and stability on the machine side，which in turn affects the DC bus voltage of the converter，leading to power fluctuations on the grid side and posing a threat to the stability of the power system. When using traditional single vector model free predictive control on the machine side，although it effectively improves system robustness，there is still a problem of poor control effect. Therefore，an improved model free predictive control suitable for permanent magnet direct drive wind power generation systems was proposed to maintain system robustness while improving steady-state control performance. Firstly，the machine side and grid side models during the joint operation of the system were analyzed. Secondly，through the method of the extended finite control set，the traditional finite control set was optimized. Combined with the model free predictive control concept of traditional current difference，the proposed method improves the prediction accuracy of the control method and reduces current and power ripple. Finally，the effectiveness and superiority of the proposed method were verified through experiments.

Flux-weakening control technology can effectively broaden the speed range of the permanent magnet synchronous machine（PMSM）， therefore， it is of great significance to the research on the flux-weakening control of permanent magnet synchronous machine. Most of flux-weakening modified the flux-weakening current command through a single PI link， and its response speed is slow and difficult to meet the high-performance control requirements， and due to the high coupling and nonlinearity of the flux-weakening loop， PI parameters setting is difficult. In order to solve the above shortage， a method of using a conversion look-up table was proposed to be added to the control system as a feedforward， having accelerated the speed of flux-weakening adjustment.While， the method of gain linearization was adopted， by analyzing the changes of the small signal model at different operating points， it solved the problem that the fixed PI parameters of the flux-weakening loop controller that have been set by experience cannot cope with the change of the operating point， which improved the stability and accuracy of the system. Finally， according to the simulation and experiments， it was verified that the improved method can improve the performance of flux-weakening control.

Three-phase asynchronous motor is one of the most frequently used motors. Inter-turn short circuit fault is a kind of fault with high probability. If the real-time monitoring of motor operation，health and safety evaluation of the operation，will be able to timely stop losses，reduce losses. An inter-turn fault diagnosis method was proposed based on extended Clarke transform and fault characteristic factor Q，analyzed the characteristics of Clarke vector of inter-turn fault of motor，modulated the Clarke vector of inter-turn fault of motor，and obtained the DC component of symmetrical component and the AC component twice the fundamental frequency in the three-phase current. The ratio of the amplitude of the component to the DC component was used as the fault characteristic factor Q to diagnose the inter-turn fault. Clarke vector spectrum was studied by characteristic factor Q，so as to judge the motor fault，and theoretical simulation and prototype test were carried out.

Transmission line tower as the normal operation of the power system of the necessary equipment，its grounding resistance accurate detection for the safe and stable operation of the entire power system is particularly important，especially in the judgment of lightning protection performance and other aspects. Thus，a multi-frequency tower grounding resistance measurement method was proposed based on radial basis function （RBF） fitting. The method was able to use multi-frequency current as an excitation under the premise of not disconnecting the tower grounding lead，measure the grounding resistance value obtained from the input current of different frequencies，and then use radial basis function neural network fitting based on these data to realize the accurate measurement of the tower grounding resistance. At the same time，the accuracy and reliability of the method was proved through the measurement of grounding resistance of multiple towers，and the proposed method is simple to operate，which largely facilitates the measurement of inspectors on the spot，and has strong practical significance.