Improved controller for power conditioner using high-temperature superconducting magnetic energy storage (HTS-SMES)

Abstract

One of the most important functions in a superconducting magnetic energy storage (SMES) system when used for power conditioning, is the ability to charge the super-conducting coil as fast as possible to ensure that it is ready when it is next required. This paper describes a novel controller for a high-temperature SMES (HTS-SMES) that can ensure: 1) fast return of energy to the superconducting coil under constant-current mode and 2) a constant and sinusoidal input supply current irrespective of the varying load demand with and without harmonics. In the new HTS-SMES proposed, two hysteresis controllers are used, one to control the magnitude, phase and the waveform of the ac supply current, and the other is to control a dc chopper to regulate the SMES coil current. The first hysteresis controller ensures that as far as the power utility is concerned, the load appears to the utility system as a constant sinusoidal load with unity power factor irrespective whether the load is distorted or varying in nature. The second hysteresis controller has been designed to regulate the energy in and out of the superconducting coil. A special feature of this controller is its ability to smoothly charge the superconducting coil using constant current charging so that it can be ready for the next discharging operation as soon as possible. Analysis of the circuit operation under hysteresis control is presented in details. Simulation and experimental results are presented demonstrating the feasibility of the proposed power conditioning system. Index Terms-Chopper, hysteresis, inverter, load leveling, power conditioning system (PCS), superconducting magnetic energy systems (SMES).

Modeling and Control of Power System Containing PV System and SMES using Sliding Mode and Field Control Strategy

“…The most applications of the SMES are: SMES is used to the transmission and distribution system stability [20], control of voltage based on active and reactive power [21] and smooth the wind farm output by absorbing or providing realpower [22], SMES can respond very quickly to the active and reactive power demand [22,23] and stabilize system frequency, the SMES is characterized by its rapid response (milliseconds) [24]and long life cycle [25]compared to other energy storage systems, it has a very high storage efficiency.…”

“…In this paper, novel Dc-Dc chopper has been proposed and investigated as it's shown in Fig 8, the SMES is charged from PV system and connected the Grid with two modes, the first mode is discharge mode, and in this mode the SMES will be controlled by PID classical regulator to regulate the error as is expressed in equation (25), the second mode is standby, in this mode the SMES is disconnected to the Grid by short circuit.…”

Future Power Distribution Grids: Integration of Renewable Energy, Energy Storage, Electric Vehicles, Superconductor, and Magnetic Bus

“…The SMES can be used as a fast acting buffer storage due to its fast response capability, which can smooth the fluctuations in solar power output. A power conditioning strategy can be designed using an SMES as discussed in [20] for application to PV power smoothening. To control the charging and discharging of the SMES, an advanced control loop for power conditioning system needs to be carefully designed and implemented to achieve this.…”

Hybrid fuel cell and energy storage systems using superconducting coil or batteries for clean electricity generation

“…Since the effective rotor resistance, R 2 /s, is very small at the time of starting compared with its value at rated slip, the starting current may be as much as 400 % to 800 % of the fullload current, leading to an excessive line voltage drop [9]. …”

“…8, the sluggish response of the fuel cell to a sudden load change means that an additional energy storage element is needed to handle the load transients. Several papers on the use of an energy storage for dynamic performance of power systems have been recently published [8,9], showing that Energy Storage System using either battery or superconducting magnetic energy storage can help in the operation of power systems, by providing active and reactive power support, emergency supply, active filtering, increased damping against transient stability and fast dynamic control of active and reactive flow in a transmission corridor. One main advantage of the storage energy systems is its fast response to load changes.…”