Z-source inverter based control of wind power

Abstract

Impedance (Z)-source inverter can provide stable output by smooth controlling of shoot-through duty cycle of any of the traditional PWM bridge inverters. In this paper a control system for impedance-source inverter is designed suitable for wind power conversion system. The main challenge in wind power system to maintain a constant voltage at the output with unpredictable variation in wind speed, is suitably taken care in steady state through buck-boost-capability of z-source inverter (ZSI). The shoot through state of ZSI is able to control and boost the output voltage when the wind generator voltage is not more enough to directly generate the desired output. Again, the nonshoot through state can control and buck the output voltage when the wind generator voltage is more than desired. So, the zsource PWM inverter replacing the conventional PWM inverter provides the unique output voltage regulation feature by making an appropriate choice of buck-boost factor. The closed loop controller carefully monitors the wind generator voltage and controls the shoot-through and non-shoot through duty cycles automatically. The whole system is simulated under arbitrary input variation condition and results are presented. A comparison between the traditional and z-source inverter based system is also presented, which clearly indicates the benefits of the proposed system. Index Terms--closed loop control, Impedance-source inverter, wind generator. VII. BIOGRAPHIES

Simulation and Implementation of Quasi-Z-Source Based Single-stage Buck/boost Inverter Fed Induction Motor

“…Moreover, the discontinuous conduction mode of the ZSI with small inductance or low load power factor and its associated circuit characteristics are analyzed [4]. The performances of the control methods of ZSI to achieve the maximum voltage output with in the prescribed limit of harmonics and THD percentages and it can also achieve the minimum passive component requirement and hence the low voltage stresss at the same time [5]. The Shoot-through zero states of the Z-Source inverter boost the low level input into higher level ac, which is not possible with the help of conventional inverter [6].…”

A small-scale standalone wind energy conversion system featuring SCIG, CSI and a novel storage integration scheme

“…Amongst the power converters which have been employed or have the potential to be employed in WECSs (i.e., VSC, CSC, ZSI, MC and IMC), VSC is the dominate topology in both large and small-scale WECSs [63]. The potential of an impedance-source inverter, as a replacement for the conventional VSI-dc booster combination in standalone WECSs, has been demonstrated in [76]- [78]. Although the use of MC and IMC, in a small-scale off-grid WECS, is a possibility, the commutation problems in MC need to be carefully addressed, and the absence of dc link component, in both configurations, complicates the integration of an electrical energy storage system.…”

“…References [76], [77] have shown the potential of ZSI to replace the conventional VSI with dc booster in standalone WECSs. In [78], a buck-boost dc/dc converter was used to integrate a storage battery unit with a ZSI-based WECS through one of the ZSI's capacitors.…”

An Improved Performance of Switched Reluctance Motor Drives Using Z-Source Inverter with the Control Rule Reduction of Fuzzy Logic Based PI Controller

“…Together with (3), (6), (8), and (9), the matrix-form behavior model of the SRM, taking the magnetic coupling effect into account, can be denoted by (10),If the mutual inductance is negligible, then Fig. 2 is the configuration of the studied SRM drive system.…”

“…Koblara proposed a fuzzy logic speed controller for SRM drives [9].Fuzzy controller can produce smooth torque and improve the system performance.Z-source inverter system for adjustable speed drives (ASD) [11]. It can produce any desired output ac voltage, even greater than the line voltage.It reduces line harmonics,and extends output voltage range.It is a relatively recent converter topology that exhibits both voltage-buck and voltage-boost capability [13].ZSI is designed suitable for wind power conversion system [10].The main challenge in wind power system to maintain a constant voltage at the output with unpredictable variation in wind speed,is suitably taken care in steady state through buck-boost-capability of (ZSI). The most concerning disturbances affecting the quality of the power in the distribution system are voltage sag/swell [12].The ZSI uses an LC impedance grid, prepares the possibility of voltage buck and boost by short circuiting the inverter legs.…”