Rising concern in environmental issues on global scale has made energy saving in powered equipment a very important subject.In order to improve the energy efficiency and driving range of a motor hoist,a regenerative b...Rising concern in environmental issues on global scale has made energy saving in powered equipment a very important subject.In order to improve the energy efficiency and driving range of a motor hoist,a regenerative braking system is designed and discussed.The system takes a unique ultracapacitor-only approach to energy storage system.The bi-directional bride DC？DC converter which regulates current flow to and from the ultracapacitor operates in two modes：boost and buck,depending on the direction of the flow.In order to provide constant input and output current at the ultracapacitor,this system uses a double proportional-integral（PI） control strategy in regulating the duty cycle of PWM to the DC？DC converter.The permanent magnet synchronous motor（PWSM） drive system is also studied.The space vector pulse width modulation（SVPWM） technique,along with a two-closed-loop vector control model,is adopted after detailed analysis of PMSM characteristics.The overall model and control strategy for this regenerative braking system is ultimately built and simulated under the MATLAB and Simulink environment.A test platform is built to obtain experimental results.Analysis of the results reveals that more than half of the gravitational potential energy can be recovered by this system.Simulation and experimentation results testify the validity of the double PI control strategy for interface circuit of ultracapacitor and SVPWM strategy for PMSM.展开更多
In this paper, a hybrid control strategy for a matrix converter fed wind energy conversion system is presented. Since the wind speed may vary, output parameters like power, frequency and voltage may fluctuate. Hence i...In this paper, a hybrid control strategy for a matrix converter fed wind energy conversion system is presented. Since the wind speed may vary, output parameters like power, frequency and voltage may fluctuate. Hence it is necessary to design a system that regulates output parameters, such as voltage and frequency, and thereby provides a constant voltage and frequency output from the wind energy conversion system. Matrix converter is used in the proposed solution as the main power conditioner as a more efficient alternative when compared to traditional back-back converter structure. To control the output voltage, a vector modulation based refined control structure is used. A power tracker is included to maximize the mechanical output power of the turbine. Over current protection and clamp circuit input protection have been introduced to protect the system from over current. It reduces the spikes generated at the output of the converter. The designed system is capable of supplying an output voltage of constant frequency and amplitude within the expected ranges of input during the operation. The matrix converter control using direct modulation method, modified Venturini modulation method and vector modulation method was simulated, the results were compared and it was inferred that vector modulation method was superior to the other two methods. With the proposed technique, voltage transfer ratio and harmonic profile have been improved compared to the other two modulation techniques. The behaviour of the system is corroborated by MATLAB Simulink, and hardware is realized using an FPGA controller. Experimental results are found to be matching with the simulation results.展开更多
基金supported by National Key Technology Research and Development Program of China (Grant No. 2007BAF10B00)
文摘Rising concern in environmental issues on global scale has made energy saving in powered equipment a very important subject.In order to improve the energy efficiency and driving range of a motor hoist,a regenerative braking system is designed and discussed.The system takes a unique ultracapacitor-only approach to energy storage system.The bi-directional bride DC？DC converter which regulates current flow to and from the ultracapacitor operates in two modes：boost and buck,depending on the direction of the flow.In order to provide constant input and output current at the ultracapacitor,this system uses a double proportional-integral（PI） control strategy in regulating the duty cycle of PWM to the DC？DC converter.The permanent magnet synchronous motor（PWSM） drive system is also studied.The space vector pulse width modulation（SVPWM） technique,along with a two-closed-loop vector control model,is adopted after detailed analysis of PMSM characteristics.The overall model and control strategy for this regenerative braking system is ultimately built and simulated under the MATLAB and Simulink environment.A test platform is built to obtain experimental results.Analysis of the results reveals that more than half of the gravitational potential energy can be recovered by this system.Simulation and experimentation results testify the validity of the double PI control strategy for interface circuit of ultracapacitor and SVPWM strategy for PMSM.
文摘In this paper, a hybrid control strategy for a matrix converter fed wind energy conversion system is presented. Since the wind speed may vary, output parameters like power, frequency and voltage may fluctuate. Hence it is necessary to design a system that regulates output parameters, such as voltage and frequency, and thereby provides a constant voltage and frequency output from the wind energy conversion system. Matrix converter is used in the proposed solution as the main power conditioner as a more efficient alternative when compared to traditional back-back converter structure. To control the output voltage, a vector modulation based refined control structure is used. A power tracker is included to maximize the mechanical output power of the turbine. Over current protection and clamp circuit input protection have been introduced to protect the system from over current. It reduces the spikes generated at the output of the converter. The designed system is capable of supplying an output voltage of constant frequency and amplitude within the expected ranges of input during the operation. The matrix converter control using direct modulation method, modified Venturini modulation method and vector modulation method was simulated, the results were compared and it was inferred that vector modulation method was superior to the other two methods. With the proposed technique, voltage transfer ratio and harmonic profile have been improved compared to the other two modulation techniques. The behaviour of the system is corroborated by MATLAB Simulink, and hardware is realized using an FPGA controller. Experimental results are found to be matching with the simulation results.
