Natural DC‐link voltage balance in a
One of the major issues with the NPC converter operation is DC-link capacitor voltage balancing. This problem is still being investigated in the case of three-level NPC
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One of the major issues with the NPC converter operation is DC-link capacitor voltage balancing. This problem is still being investigated in the case of three-level NPC
Free QuoteIn this article, an improved dc capacitor voltage balancing control is proposed for single-phase cascaded H-bridge (CHB) multilevel converters. Compared with conventional voltage balancing control methods, the proposed scheme has a comprehensive consideration of three aspects while balancing the capacitor voltages among H-bridges: coupling effect
Free QuoteThis study presents a DC-voltage-balancing strategy that uses a high-performance controller. Indirect-sliding-mode (ISM) control is used in the current control loop
Free QuoteThe main feature of the proposed SVM switching strategy is that it enables voltage-balancing of the DC capacitors, under steady-state and transient conditions, with no requirements for additional control actions or auxiliary devices. A dynamic model of the five-level STATCOM for power system studies is also developed.
Free QuoteAbstract: A capacitor voltage balancing method for a modular multilevel dc (MMDC) converter is proposed. The MMDC inherits the desirable features of both a modular multilevel converter (MMC) and a dual active bridge, namely high voltage capability, fault tolerance, zero-voltage switching-on of all the power devices, and a wide operating range.
Free QuoteThis paper presents a novel dc capacitor voltage balance control method for cascade multilevel static synchronous compensator (STATCOM) and a general analytical method for balance control strategy. Considering that the imbalance of dc capacitor voltage is caused by the inconsistency of active power absorbed and consumed by chain, a balance control
Free QuoteFirst, the traditional method of voltage balance strategy based on redundant vectors is described, and the key factors leading to the DC-link capacitor voltage fluctuation is
Free QuoteIn this paper, a voltage balancing algorithm (modified space vector modulation) is proposed for perfect balancing of the capacitor voltages. The mechanism responsible for producing the
Free QuoteA high voltage matrix converter for interconnecting two AC power networks has been described previous in which the links bridging the phases of the two AC networks are formed from a large number of capacitive submodules linked in series. The operation of the converter was described, including the method of maintaining the charge in the individual submodules equal
Free QuoteDC Capacitor Voltage Balancing Control for Delta-Connected Cascaded H-Bridge STATCOM Considering Unbalanced Grid and Load Conditions Abstract: In this paper, a comprehensive control scheme for a delta-connected cascaded H-bridge (CHB) converter-based static synchronous compensator (STATCOM) is presented, especially focusing on improving
Free QuoteSecondly, the principle of voltage balance control of the inverter is described, and the objective function characterizing the DC-link capacitor voltage fluctuation is derived, to get the relation
Free QuoteIn order to eliminate voltage deviations under steady-state and dynamic conditions, the active voltage-balancing control (AVBC) methods of floating capacitors and dc-link capacitors based
Free QuoteIn addition, an overall power control loop and a reactive power compensated loop are introduced as well to guarantee the normal operation of the STATCOM. In addition, the DC capacitor voltage balance can still be kept when the load suddenly changes, and the voltage balancing strategy can respond quickly when it is enabled.
Free Quotecapacitor voltage balancing ISSN 1755-4535 Received on 5th January 2017 Revised 16th September 2017 Accepted on 30th October 2017 However, a multi-output boost converter connected to the dc link''s capacitors was the means for regulating the capacitors'' voltages, rather than a process ''internal'' to the inverter.
Free QuoteSince DC-side voltage of MMC is maintained by the sub-module capacitive voltages in series, The traditional sub-module capacitor voltage balancing control determine the
Free QuoteThis paper presents control methods that achieve DC-link capacitor voltage balance of a series half bridge (SHB) LLC resonant converter operating at different modulation schemes. The principle of the proposed balancing control method is analyzed and studied based on six normally used operation modes of the SHB LLC converter. DC-link capacitor voltage
Free QuoteAt the same time, dc-link capacitor voltage balance control is complex and unattainable with a passive front end , . Five-level flying capacitor (FC) converter requires a lot of floating capacitors which increase the volume and cost of the system , . Five-level
Free QuoteAbstract: Capacitor voltage balancing is a critical issue for neutral-point-clamped-based converters, including the two/three-level dual-active-bridge dc–dc converters. The unbalanced capacitor voltage will increase the voltage stress on power devices and negatively
Free QuoteCapacitor voltage balancing is a critical issue for neutral-point-clamped (NPC)-based converters, including the two-three (2/3)-level dual-active-bridge (DAB) DC-DC converters. The unbalanced
Free QuoteSaeedifard M., Iravani R., and Pou J. Control and DC-capacitor voltage balancing of a space vector-modulated five-level STATCOM IET Power Electron. 2 3 203-215 2009 Crossref Google Scholar
Free Quotefor on-chip power supply, hybrid DC–DC converters such as flying capacitor multi-level DC–DC converter have been reported [1–4]. The flying capacitor multi-level DC–DC converter should keep the voltage of the flying capacitor, C FLY, at the desired level to ensure device reliability. Also, phase current balancing is a major challenge
Free QuoteDC voltage links of three-phase power converters are frequently equipped with a series connection of two electrolytic capacitors because of high voltage level. For such a
Free QuoteHowever, when the proposed capacitor voltage balancing strategy is introduced, the capacitor voltages become balanced, as shown in Fig. 28 (b) and Fig. 29 (b). The voltage difference is significantly reduced to ± 1.5%. Based on these results, it is concluded that the proposed capacitor voltage balancing strategy is a viable solution.
Free QuoteIn this paper, a simple auxiliary unit is inserted in the DC-link to enable a self-balancing capacitor voltage. The auxiliary circuit is composed of two capacitors and four active switching devices. The idea of the proposed
Free QuoteThe key factors that influence the DC-link capacitor voltage balance under the NPC/H-bridge topology are summarised. A new optimised voltage balance strategy based
Free QuoteFigure 1a shows the 5L-HT inverter with the auxiliary balancing circuit (ABC) needed for the DC-link capacitor voltage control. The ABC consists of two active switches, one diode and two inductors. Since the middle capacitors (({C}_{1}, {C}_{2})) of the 5L-HT inverter are naturally discharged when the LSPWM is applied, the ABC is utilized to boost the
Free QuoteThis paper develops a generalized Pulse Width Modulation approach to eliminate both the low frequency oscillations and imbalances in the dc-link capacitor voltages, which are the main drawbacks of diode clamped converters. The algorithm has been developed within the Carrier-Based PWM framework to facilitate its implementation in diode clamped converters with four
Free QuoteThis paper presents the active capacitor voltage-balancing (ACVB) methods based on the dynamic model for a five-level nested neutral-point piloted (NNPP) converter using hybrid carrier modulation. The traditional hybrid carrier modulation provides natural voltage balancing of floating capacitors and dc-link capacitors. First, the natural voltage-balancing ability under steady-state
Free QuoteThe capacitor voltage balancing is an important issue for 5L-ANPC inverters. In –, the Space Vector Modulation (SVM) is used to generate five-level output and balance the voltages of DC-link capacitors and FC. In , , the technique of zero sequence voltage injection is used to balance the DC-link capacitor voltages.
Free QuoteThe proposed OCC voltage-balancing technique of the dc-link capacitors is capable of keeping the dc-link capacitor voltages balanced even when the four dc-link
Free QuoteThe dc capacitor voltage balance control is essential for a single-phase CHBR. However, existing dc capacitor voltage balance control methods suffer from lacking regulation range. To tackle this issue, a balance control method for dc capacitor voltage to extend the regulation range that is readily implemented is proposed in this article, whose
Free QuoteThis paper proposes a new DC-link capacitor voltages balancing technique for the Seven-Switch 5L-ANPC (7S-5L-ANPC) topology which is using Phase-Shifted PWM (PS-PWM) modulation method. Based on the power relationship between DC-link capacitors and FC, the proposed technique adjusts the duty cycles of redundant 1-level switching states to balance the DC
Free QuoteDC-link capacitor voltage balancing strategies are developed separately for two common modulation schemes in SHB topology. The performance of the proposed voltage balancing control method is experimentally verified on a 7.5-kW SHB LLC DC/DC converter prototype under different operating conditions.
Free QuoteThis paper proposes a new DC-link capacitor voltages balancing technique for the Seven-Switch 5L-ANPC (7S-5L-ANPC) topology which is using Phase-Shifted PWM (PS-PWM) modulation
Free QuoteDC voltage links of three-phase power converters are frequently equipped with a series connection of two electrolytic capacitors because of high voltage level. For such a configuration, usually resistors have to be arranged in parallel to each capacitor in order to balance the partial voltages. These balancing resistors, however, have to be dimensioned
Free QuoteThe flying capacitor multi-level DC–DC converter should keep the voltage of the flying capacitor, C FLY, at the desired level to ensure device reliability. Also, phase current balancing is a major challenge for the design of
Free QuoteThe capacitor of DC link charges and discharges and can be observed in capacitor voltage waveforms of DC link. The flying capacitor voltage is balanced to V dc /4.
Free QuoteThis paper establishes that the average capacitor voltage of each arm is self-balanced and proposes a method to balance voltages within an arm by assigning the gate
Free QuoteThis paper presents a capacitor voltage balancing control applicable to any multilevel dc-ac converter formed by a single set of series-connected capacitors implementing
Free QuoteFor this reason DC link capacitors voltage balancing is crucial task in such configuration. The focus of this paper is a three-level three-phase neutral point clamped inverter.
Free QuoteAbstract: Capacitor voltage balancing is a critical issue for neutral-point-clamped-based converters, including the two/three-level dual-active-bridge dc–dc converters. The unbalanced capacitor voltage will increase the voltage stress on power devices and negatively affect the reliability of the converters.
The real-time simulation results and the experimental results show that the optimised voltage balance strategy can effectively inhibit the fluctuation of DC-link capacitor voltage difference, and it can greatly reduce the energy loss in the neutral point circuit.
The behaviour of a capacitor in DC circuit can be understood from the following points − When a DC voltage is applied across an uncharged capacitor, the capacitor is quickly (not instantaneously) charged to the applied voltage. The charging current is given by,
This study proposes a voltage balancing scheme for flying capacitors multilevel converters. The strategy is based on the redundancy of switching states. By using analytic expressions, the authors study the balancing properties of each switching state.
The balance of the capacitor voltages is achieved by using the state and voltage vectors redundancies. For the available voltage vectors, each redundant state is evaluated by a cost function – taking into account the voltage errors – to choose the state that minimises such function.
Two typical problems during the capacitor voltage balancing process should be solved, i.e., power fluctuation minimization and determination of the transformer current polarity. Accordingly, this article proposes a balancing control scheme based on the complementary switching-state (CSS) method.