Power optimizer

About: Power optimizer is a research topic. Over the lifetime, 10525 publications have been published within this topic receiving 199245 citations.

Effects of the synthetic inertia from wind power on the total system inertia: simulation study

Abstract: The future power systems face several challenges; one of them is the use of high power converters that virtually decouple primary energy source from the AC power grid. An important consequence of this modified the total system inertia and affecting its ability to overcome system frequency's disturbances. The wind power industry has created a controller to enable inertial response on wind turbines generators: Synthetic Inertial. This paper evaluates the effects of the synthetic inertia provided by wind turbines on the total system inertia after a system frequency disturbance. The main contribution of this paper is to demonstrate that during an under-frequency transients on future power systems, the synthetic inertia not completely avoid worse scenarios in terms of under-frequency load shedding. The extra power delivered from a wind turbine during frequency disturbances can increase “momentary” the total system inertia and substantially reduce the rate of change of frequency providing time for the active governors to respond. However, synthetic inertia might not completely avoid under-frequency load shedding.

Constant-Bandwidth Maximum Power Point Tracking Strategy for Variable-Speed Wind Turbines and Its Design Details

Abstract: Implementation of maximum power point tracking (MPPT) control to variable-speed wind turbines below the rated wind velocity helps the turbine improve its efficiency, thereby increasing its annual energy yield. However, for the most commonly used optimum power (OP) MPPT method, it is proved to have the drawback of low tracking speed. Moreover, what is worse, the tracking bandwidth will get narrower when the turbine is operating under low wind velocities, which results in the reduction of annual energy yield. To overcome this drawback, an improved MPPT method, which is improved from the conventional OP control method, is designed in this paper to broaden the MPPT bandwidth. The design details on how to realize the improved MPPT method and the principle of choosing a proper system dynamics are both pointed out after analyzing the system dynamics in frequency domain. The theoretic analysis is verified by simulation and experimental results performed by a 1.2-kW variable-speed wind turbine.

Fast Power-Peaks Estimator for Partially Shaded PV Systems

Abstract: Model-based maximum power point tracking (MPPT) techniques have been developed recently to improve the dynamic and steady-state performance of MPPT. Although they are successfully implemented in homogeneous photovoltaic (PV) systems, there is still no model-based MPPT for partially shaded PV systems, mainly because the available models are complex and time consuming. This paper develops a fast modeling approach for partially shaded PV systems. By utilizing three developed rules that govern the formation of power peaks in partially shaded PV systems, the proposed approach can quickly find the power peaks of these systems without simulating the entire power curve. The effectiveness of the proposed approach in finding the power peaks of PV systems quickly and accurately is verified using MATLAB-Simulink and real-time simulator in hardware in the loop application. Moreover, a model-based MPPT is developed utilizing the proposed modeling method. The developed MPPT successfully improves the dynamic performance of power extraction, guarantees the operation on the global maximum power peak, and eliminates oscillating steady-state power losses.

Power supply system for vehicle with improved energy efficiency and vehicle including the same

Abstract: A matrix converter (38) converts three-phase AC power input from a first motor-generator (MG1) directly to three-phase AC power for driving a second motor-generator (MG2) and outputs the resultant three-phase AC power, without rectifying the three-phase AC power generated by the first motor-generator (MG1) once to DC power as in an example using a conventional three-phase full-wave rectification inverter. In a power supply system for a vehicle (14), the three-phase AC power is transmitted and received between two motor-generators (MG1, MG2) more directly, by means of the matrix converter (38). Therefore, power loss can be reduced, as compared with a conventional example in which the three-phase AC power is once converted to DC power. Thus, a power supply system for a vehicle with improved energy efficiency and a vehicle including the same can be provided.

Hybrid vehicle and control method therefor

Abstract: A hybrid vehicle and a control method of the hybrid vehicle is provided, capable of suppressing discharge of the battery at the time of starting a DC/DC converter and suppressing temporal voltage drop of the battery. When the engine is in the idle state and the power generated by the motor is not sufficient, the motor controller starts the DC/DC converter at a low output voltage state, and the amount of power generated by the motor is gradually increased at a speed without disturbing the idle rotation of the engine, and when it is determined that the power generation by the motor is sufficiently high by comparing the amount of power generation with the amount of power consumption at the output of the DC/DC converter, the operation mode of the output variable DC/DC converter is switched from the low voltage mode to the high voltage mode.