The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Neutral point potential oscillation at low frequency is an important issue in four pole neutral point clamped converter since this leads to the extra voltage stress on the split DC-link capacitors. The detailed analysis indicates such oscillation is closely associated with the neutral point current at low frequency, so this paper explores their relationship, and presents the modulation techniques...
This paper investigates the effect of neutral point potential oscillation on four pole neutral point clamped converter. The detailed derivation indicates such oscillation is closely associated with neutral point current, so this paper presents a modulation technique to effectively eliminate this neutral point current. Besides, an offset injected method is also taken into consideration, and a comparison...
This paper investigates the effectiveness of virtual synchronous machine based on three-phase voltage source converter. The virtual machine can effectively slow down frequency dynamics in micro-grid, which is achieved by emulating the damping and inertia of synchronous machine. Besides, the theoretical analysis indicates the virtual synchronous machine is closely related to the conventional droop...
This paper investigates the effects of pulse width modulation (PWM) on the circulating current of parallel-connected four-pole inverters (FPIs). Detailed mathematical modeling shows that the common-mode voltage (CMV) outputs of PWMs are closely related to the circulating current, so this research presents the reduced CMV PWM techniques for FPIs to reduce the circulating current, and compares their...
Three-level neutral-point-clamped (NPC) converters/inverters have become a popular topology for not only medium-voltage (1k–33k) but also low-voltage level industrial application because of its reduced transistor block voltage and lower output current distortion. The neutral point voltage balancing control is one of the important issues of NPC converter to ensure system operation since the voltage...
This paper investigates different compensation methods for neutral point potential deviation based on modular multilevel single star neutral point clamped bridge converter. Theoretical analysis indicates injecting an offset for a cell can effectively decrease this deviation, so this research presents different offset-based compensation techniques, and evaluates their output performance. Besides, this...
Common mode voltage output is closely associated with switching states in three-phase three-wire neutral-point clamped inverter. Detailed analysis shows avoiding redundant states can effectively improve the common mode voltage, so this paper proposes a pulse width modulation (PWM) technique with zero redundant states to reduce the common mode voltage output, and evaluate their performance with the...
Parallel-connected four-pole inverters (FPIs) becomes an important application in three-phase four-wire uninterrupted power system, owing to the benefits like high reliability, cost-effective and the convenient expansion of power capacity. Nevertheless, such parallel connection would lead to the side-effects, just as the circulating current, accompanied by extra loss and current distortion. The difference...
Connecting the four-pole inverters (FPIs) in parallel has many benefits, like lower cost, high flexibility and excellent reliability, and becomes a favorite option in industry. However, such side effects of parallel connection as the circulating current will lead to severe distortion and extra loss. The circulating current is mainly caused by the difference of common mode voltage (CMV) and closely...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.