| In view of the common problems of traditional wave energy generation devices,such as the fluctuation of capture base point,many energy conversion links and low capture efficiency,an inverted wave energy generation system is proposed,in which the wave energy generation device is upside down on the fan tower platform,and the wave energy generation device is installed on the wind turbine tower platform.In order to ensure the axial motion resonance and capture the maximum energy,the float is used to convert the axial motion energy of the wave into the output energy of the linear generator,which is controlled by the counter-magnetic force of the converter at the side of the converter in order to ensure the axial motion resonance of the float and capture the maximum energy.In this paper,the structure design,model construction,performance analysis,control strategy and simulation experiment of the inverted wave energy generation system are studied.A 15 kW inverted wave energy generation system is designed based on the Rizhao ocean conditions(wave height 0.6m and wave period 2.7s).Based on the variation of kinetic energy and potential energy in wave period and the average output power of generator,the weight and volume of float are optimized according to the principle of conservation of energy.Considering the wave height,the period and the rated speed of the linear generator,the speed-up ratio of the speed-up mechanism is optimized,and the type selection of the linear generator and the design of the converter on the side of the generator are completed according to the requirements of the power grade and the output voltage.Taking buoyancy force,damping force,spring force and antimagnetic force into account,the dynamic model of wave energy capture system is constructed to complete the wave energy.Performance analysis of capture system.Aiming at the model resonance velocity setting offset caused by wave eigenvalue extraction error,the phase-locked loop technique of single-phase alternating current signal is introduced into the extraction of wave energy characteristic value.According to the measured wave height,period and differences between the multi-buoy sensors,a single-phase AC signal phase-locked loop technique is introduced.The extraction and correction strategy of wave eigenvalues is proposed.In view of the problem of reference speed setting deviation caused by equipment aging and model mismatch,a disturbance optimization strategy based on capture power feedback is adopted to complete the optimization speed setting.The essence of high efficiency wave energy capture is the fast tracking control of optimal speed without static error,but the optimized velocity is the alternating current signal with time varying frequency.In view of the stator current transfer of linear motor,the optimal velocity is a time-varying AC velocity signal with time-varying frequency.The torque and excitation current are coupled seriously.A variety of magnetic field-oriented strategies are compared and analyzed.Rotor flux orientation is used to decouple stator current to realize independent control of torque and excitation current,and double closed-loop strategy of rotating speed outer loop and current inner loop is adopted.Aiming at the nonlinear,time-varying and strong disturbance problems of wave energy capture,an optimal velocity tracking control strategy based on adaptive compensation is proposed.The torque-current reference is given,and the current tracking controller is combined with the current-tracking controller.Efficient wave energy capture is achieved in collaboration.The simulation experiment platform of 15 kW inverted wave energy generation system is built.The capture performance comparison experiment of model resonance multi-velocity tracking control and disturbance-seeking multi-speed tracking control are carried out respectively,and the model resonance experiment is carried out.The speed tracking error of adaptive compensation control is 0.009m/s,and the capture power is 11530 W,which is much better than PI control(0.062m/s and 10527W)and PR control(0.038m/s and 10981W).In the disturbance optimization experiment,the disturbance optimization time of adaptive compensation control is 33.9s,and the additional power is 818 W.It is far better than PI control(48.9s and 1403W)and PR control(41.9 s and 1093W),and through comprehensive comparison,the adaptive compensation control strategy based on disturbance optimization is superior in the aspects of velocity tracking error,disturbance optimization time and global capture power,etc.It is the most suitable maximum power acquisition control strategy for inverted wave energy generation system to solve the problem of fast non-static error tracking control of reference velocity setting deviation and optimized velocity caused by model mismatch effectively and to achieve high efficiency wave energy capture. |
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