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The utility-scale renewables, PV and wind, are already approaching grid parity. To further enhance their penetration rapidly requires additional cost reduction and increased efficiency. There are other applications in utility-scale energy storage systems and in substations with power ratings in MW range for rapid charging of multiple electric vehicles. Towards this goal, one approach to interface...
Aluminum electrolytic capacitors (AECs) are the most common capacitors used in power electronics. They are frequently used for filtering and storage functions because of their small size, large capacitance and low price. However, AECs also represent the major cause for power electronics equipment breakdown, mainly due to their wear out through the vaporization of the electrolyte, as a result of both...
According to the requirement of the power factor and the dynamic performance of the asynchronous machine tool field, an asynchronous motor inverter with active power factor correction is proposed. The proposed inverter is a 3kW asynchronous motor drive control platform. At first, the proposed single phase converter with APFC is realized by using the MATLAB/SIMULINK. Then, the boost APFC is designed...
Even though some methods have been put forward to solve the drift problem and the low frequency fluctuation problem of the neutral point potential (NPP) for three level neutral point clamped converters (TL-NPC), they are all just suitable for SPWM or SVPWM technologies. In some medium/high voltage high power applications, where SHEPWM is utilized to modulate the reference voltages, the drift problem...
It is conceivable that the future fleet of US Navy vessels will deploy multiple high power AC and DC loads that must be reliably energized. Integration and operation of AC and DC loads will likely be achieved using an intelligently controlled microgrid architecture that is able to actively regulate and distribute power from both AC generation sources and DC energy storage devices. Some future loads...
This paper presents a novel control strategy to reduce the DC-link voltage ripple for electrolytic capacitor-less PMSM drive system. By injecting the 3rd harmonic current into the driver system, the instantaneous power balance between the grid output power and the motor output power is achieved, so the DC-link voltage ripple is reduced obviously. For further improving the PMSM performance under DC-link...
This paper presents a seven level inverter utilizing switched-capacitor technique. Proposed topology employs two asymmetric DC voltage sources as input and generates a multilevel staircase output. The structure includes a front-end switched-capacitor based DC-DC converter cascaded by a back-end H-bridge inverter. The frontend SC DC-DC converter feeds three DC voltage levels to the H-bridge inverter...
This paper presents the design and steady-state analysis of a Fixed Capacitor-Thyristor Controlled Reactor (FC-TCR)-based Static VAr Compensator (SVC). Reactive power compensation is demonstrated through the fundamental frequency analysis of the samples acquired from the designed system. The performance of the SVC in the presence of line reactance is also discussed. National Instrument (NI) based...
Aiming at the problems of slow dynamic response and high harmonic content for single phase magnetically controlled reactor (MCR), a comprehensive compensation system based on MCR and active power filter (APF) is proposed and the system topology is introduced. In the system, MCR is taken to compensate reactive power, while APF is taken to compensate harmonics generated by both load and MCR. Meanwhile,...
This paper has focused on the modified sensorless method for PMSM drive, which could estimate the rotor position information with the small DC-link capacitor. Due to the evaporation of electrolyte with working time, the electrolytic capacitor is vulnerable to the current ripple and heat. Thus, the film capacitor is selected as the DC-link capacitor in recent years. However, the capacitance of film...
This paper presents a new implementation of flyback-type inverter to optimize power flow from solar PV (photovoltaic) system. The flyback-type inverter used is Shimizu topology. The main features of this inverter type include: extended lifetime of the inverter, provide small volume, lightweight, lower harmonic content and stable AC current injection into the load or utility line. Three controllers...
In this work, a new grid synchronization control strategy is developed for a single stage three phase grid coupled Photovoltaic system that employs Kalman Filter Algorithm (KF) to estimate the fundamental sinusoidal components of the Point of common connection (PCC) voltage and load current respectively. The DC-link bus capacitor voltage is regulated employing a Proportional-Integral (PI) controller...
The modular multi-level converter (MMC) is considered as the state of the art converter among multilevel topologies. The harmonic suppression of circulating current is the inherent problem needed to be solved. In this paper, a new control strategy is proposed. The strategy includes the double fundamental frequency, negative sequence rotating coordinate transformation and the four fundamental frequency,...
The boost inverter can be an alternative grid interfacing power converter for renewable energy sources since it can generate an AC voltage whose peak value could be greater than the DC voltage. When it connects to the grid, high quality output current is required, therefore, grid current is hoped to be controlled directly. A novel control strategy to control grid current with only one closed control...
This paper presents sequence impedance modeling and analysis of modular multilevel converters (MMC) in a single-star configuration for Static VAR Compensation (STATCOM) application. Prior work on impedance modeling of MMC has focused on the double-star configuration for high-voltage dc (HVDC) transmission applications. In the single-star configuration, each phase uses only a single arm of switching...
The grid-voltage unbalance can result in a double-frequency component in the output power of a three-phase grid-connected converter, which significantly degrades the system performance. To address this issue, the power decoupling concept, which was previously developed for the single-phase system to handle the double-frequency power oscillation, is applied to the three-phase system in this paper....
Single-phase power converters are commonly employed to integrate renewable sources, such as solar PV or fuel cells, among other applications. However, they typically require large and limited lifetime electrolytic capacitors to filter large DC side ripple components, representing a limit for the power density and durability of converters, potentially making the technology unpractical for some applications...
An internal paralleled active neutral point clamped converter (IP-ANPC) is presented in this paper. Advantages of the IP-ANPC converter include modularity, reliability and efficiency improvement, capability of interleaving, and better utilization of wide band-gap (WBG) devices. To simplify the operation of the IP-ANPC converter and provide an easy interleaving solution, a logic-based flying capacitor...
This paper proposes a new induction motor drive scheme to generate a dense multilevel dodecagonal space vector structure, by stacking two 3-level flying capacitors and cascading two H-bridges. The proposed scheme combines the benefits of both multilevel as well as dodecagonal voltage space vector structure. All the capacitors in the stacked inverters are balanced using switching state redundancies...
In the conventional variable speed drive, the dc-link including the dc-choke and electrolytic capacitor is bulky with limited lifetime. The slim dc-link drive is thus proposed for the lower cost and longer lifetime by using the film capacitor to replace the electrolytic capacitor and dc-choke. However, such drive system suffers from the potential instability issue, due to the negative incremental...
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