Simulated topology of doubly powered asynchronous motor with diode clamped inverter

Abstract

This paper deals with the problem of modelling, control and analysis of a doubly-powered induction machine (DPIM) using a three-level three-phase voltage source inverter known simply as diode clamped inverter (DCI) with a three-phase diode rectifier and a DC link in between. A mathematical model of DPIM and the associated DCI circuit is developed. The stator circuit of the DPIM is supplied directly from an ac system network while its rotor side is supplied via a variable frequency DCI. A multi-loop nonlinear field controller is developed to meet an accurate motor speed, regulation of the mechanical load torque and the overall system power. The results obtained from the simulation in the environment of Simplorer 7 show that the proposed DCI inverter offers great optimisation, little overshoot, and reduced voltage ripples. Consequently, the dynamic behaviour of the motor and the energy efficiency of the overall system are progressively improved and a complete suppress of the influence of the variation in the motor load on the speed of the motor is achieved.

Modeling and simulation of a stand-alone wind turbine supplying an inductive load through a long cable

“…) 3 𝐶 𝑝(max) = 𝑘 𝜔 𝑡𝑢𝑟 3 (4) Dividing in (4) by the WT angular velocity 𝜔 𝑡𝑢𝑟 , then the turbine torque is obtained by (5).…”

“…Where 𝑘 = ) 3 is constant. The (4) and (5) indicate that the maximum extractable turbine power is directly proportional to the cubic WS, and the turbine torque is proportional to the square WS [14]- [16]. The (2) shows that the WT power depends on two terms.…”

“…The former is usually used as an ultimate solution, but it requires additional power devices that increase the cost and complexity of the system. The alternative solution adopted in this paper is the use of a diode-clamped three-level three-phase voltage source inverter installed with three neutral levels [5]. It is known that the same control and modulation circuit described for the DFIG with the two-level back-to-back frequency converter can be applied for the three-level MLFC.…”

“…It is known that the same control and modulation circuit described for the DFIG with the two-level back-to-back frequency converter can be applied for the three-level MLFC. The only difference is that the three-level MLFC also needs an equalizing scheme for the DC-voltage power outlet as discussed in [5], [8].…”

“…There is no specific definition of small-scale WTs. This paper assumes the capacity of small WTs to be from about 1 kW to 100 kW, with a generation voltage level of less than 1kV [5]. The speed at which WTs operate is usually fixed or variable, although the variable-speed operation is preferred.…”