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The increasing implementation of Distributed Generation (DG) in the distribution grids creates new challenges in controlling the voltage profile. If the DG production exceeds the load consumption, the power flow reverses through the MV/LV substations. The reverse power flow impacts mainly on the voltage profile, increasing further the voltage in LV and MV grids. At this regard the Smart Transformer...
In this paper, we present a new technique to unify and intensify the magnetic fields that results in higher performance of Anisotropic Magneto-Resistive (AMR) current sensors and consequently develop a closed loop controller for 100W synchronous GaN buck converter at 1MHz. The closed loop operation of high switching frequency converters at high power has always been a big challenge due to lack of...
This paper proposed a distributed control method for dc microgrid to ensure the proportional load sharing by taking into account the different line impedance. In the proposed method, the operation point of each DG is effectively defined based on the power rating and the instantaneous power of the DG to achieve the proportional load power sharing. A low bandwidth communication is used to transmit the...
The decoupling of the capacitor voltage and inductor current has been shown to improve significantly the dynamics performance of voltage source inverters in isolated microgrids. However, still the computation and PWM delays limit the achievable bandwidth. A technique based on a lead compensator structure is proposed to overcome this limitation. It is shown how a widen bandwidth for the current loop...
In stand-alone microgrids based on voltage source inverters state feedback coupling between the capacitor voltage and inductor current degrades significantly the dynamics performance of voltage and current regulators. The decoupling of the controlled states is proposed, considering the limitations introduced by system delays. Moreover, a proportional resonant voltage controller is designed according...
In industrial applications, power quality has been an issue drawing increasing concerns due to its severe consequences on system performance and downtime cost. Voltage sags are classified as one of the most common power quality issues. In order to guarantee system operation under several line sag scenarios, international standards such as SEMI F47, IEC-61000-4-34, and IEC-61000-4-11 have been established...
Stability and rapidity of phase angle detection in grid synchronization system is very important, especially when grid voltage is under adverse conditions. This paper presented a fast direct calculation phase-locked loop (FDC-PLL) method which can detect phase angle directly from the corresponding relationship between the absolute value of grid voltage and the phase angle. And the d-q conversion is...
The junction temperature of power semiconductors in power converters must not exceed its maximum limits and it is of major importance for several failure mechanisms. But still, the junction temperature is hard to access. Direct measurement is not practical for industrial applications, indirect measurements require substantial effort and available junction temperature models have high calculation effort...
Full speed sensorless Interior Permanent Magnet Synchronous Motor (IPM-SM) drives estimate the rotor speed and position by means of a HF voltage injection at standstill or low speed operation and by some form of back-electromotive force or PM flux estimator at the medium and high speed range. Both the estimation strategies include an inner loop closed by a PI+I regulator for extracting speed and position,...
This paper deals with a model-based state-space flux-linkage control of a dual three-phase-winding bearingless synchronous reluctance motor. Analytical tuning rules for the state feedback, integral action, and reference feedforward gains are derived in the continuous-time domain. The proposed method is easy to apply: the desired closed-loop bandwidth together with the estimated magnetic-model of the...
Differential-mode Ćuk inverter (DMCI) represents a class of single-stage inverter with low device count, modular symmetry, and topological simplicity. Recently, discontinuous modulation scheme (DMS) has been proposed for the DMCI. This paper extends the modular nature of the power stage to the control architecture and proposes a transformation-based tracking controller using adaptive control algorithm...
The main theme of this paper is to propose fast on-line optimal bandwidth search and controller tuning techniques for servo motor drives. The proposed controller tuning method derives the controller gains by searching the optimal bandwidth and identifying the inertia. The optimal bandwidth can be achieved before oscillation occurs. It will be shown the gains of speed controller of servo drives are...
The maximum torque per ampere (MTPA) control has been widely employed to improve the efficiency of the permanent-magnet synchronous machine (PMSM) drive systems. To achieve accurate online MTPA tracking, in this work, a high-frequency current injection based method is proposed. Compared to the lookup-table based MTPA control, the proposed method can significantly reduce the pre-tuning effort. Since...
In the control of Interior Permanent Magnet Synchronous Machines (IPMSMs), Maximum Torque Per Ampere (MTPA) based on motor parameters is a common approach to achieve high efficiency and torque density. Parametric uncertainty (e.g. due to identification errors, magnetic saturation or temperature variation) results in undesired deviation from the optimal operating trajectory. To solve this problem,...
The stringent requirements on both the control bandwidth and the supply standby current make it tough to design the IC controllers for the v-core converters in future computer applications. The effects of the non-ideal characteristics of the finite gain-bandwidth product and non-zero output impedance of an operational amplifier (OP) are investigated for such a purpose. The results show surprising...
The aim of this paper is to reduce the low-speed limitation of PMSM drives that use low-resolution position sensors. It is recognized, for the first time, that this may be overcome by merging signal-injection-based self-sensing and low-resolution sensor technologies, if the machine possesses a detectable amount of electromagnetic saliency. The supplementary information coming from the injection of...
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