Power electronics plays an important role in a wide range of applications order to achieve high efficiency and performance. Increasing efforts are being made improve the reliability power systems ensure compliance with more stringent constraints on cost, safety, availability different applications. This paper presents overview major failure mechanisms IGBT modules their handling methods converter improving reliability. The presented first, for predicting lifetime estimating junction...

Transformerless topologies of many are widely used in photovoltaic (PV) systems because these have advantages terms the weight, size, and efficiency. A three-level inverter has an outstanding performance is advantageous switching device selection than a two-level inverter. In transformerless PV using inverter, should suffer from leakage current generate neutral-point voltage unbalance. To solve two problems, this paper proposes modulation techniques to reduce balance dc-link voltages. The...

This paper proposes a fault-tolerant control strategy for T-type three-level inverter when an open-circuit fault occurs. The proposed method is explained by dividing into two cases: the faulty condition of half-bridge switches and neutral-point switches. In case in switch, methods will be compared based on thermal analysis voltage oscillation. reliability systems improved considerably algorithm switch fails. does not require any additional components. Simulation experimental results verify...

This paper proposes a new diagnosis method of an open-switch fault and fault-tolerant control strategy for T-type three-level inverter systems. The location the faulty switch can be identified by average normalized phase current change neutral-point voltage. proposed is explained dividing into two cases: condition half-bridge switches switches. performance system improves considerably algorithm when fails. does not require additional components complex calculations. Simulation experimental...

This paper presents an open-circuit fault detection method for a grid-connected neutral-point clamped (NPC) inverter system. Further, fault-tolerant control under in clamping diodes is proposed. Under the condition, it impossible to identify location of faulty switch by conventional methods which usually use distortion outputs because same some cases. The proposed identifies and diode NPC without any additional hardware or complex calculations. In case faults, can transfer full rated power...

This paper presents a control scheme for the dynamic performance improvement of an AC/DC converter using model predictive direct power (MPDPC) with duty cycle. In MPDPC, active and reactive is simultaneously controlled single cost function. If either two targets has large variation, weight concentrated on one side, which causes mutual interference. Because such interference, dynamics deteriorates. Due to being side function, even if other decreases, system improved by reconfiguring function...

The conventional three-level active-neutral-point-clamped (ANPC) inverter requires high dc-link voltage at least twice the peak of ac output. To reduce voltage, a recent topology that enhanced gain from half to unity has been presented. In this letter, an alternative ANPC is established by using two T-type inverters. Two floating capacitors with self-voltage balancing capability are integrated achieve voltage-boosting 1.5. addition, proposed capable generating seven levels. Its operation...

This paper proposes a new family of multilevel inverter topology that is able to generate seven voltage levels by utilizing one or two floating capacitors and 10 power switches. novel boost switched-capacitor seven-level possesses boosting capability with an achievable maximum level 1.5 times the input direct current (dc) voltage. The generation higher output does not incur high-voltage stress on any switch in this topology, as peak inverse voltages all switches do exceed source In addition,...

A torque ripple reduction technique of direct control (DTC) for high power induction motors driven by three-level inverters with the inverter switching frequency limited around 0.5-1 kHz level is presented. It noted that conventional two-level DTC algorithms to reduce are devised applications relatively above 2-3 and cannot accomplish satisfactory systems such lower frequencies. new algorithm, especially low system, illustrates quite reduced characteristics all over operating speed region....

This paper proposes a fault-detection method for an open-switch fault in the switches of grid-connected neutral-point-clamped inverter systems. The proposed can not only detect condition but also identify location faulty switch. In method, which is designed by incorporating simple switching control conventional detected on basis radius Concordia current pattern, and switch be identified. By using it possible to within two fundamental periods, without additional sensors or performing complex...

This paper proposes a simple and effective method to reduce torque ripples for the predictive control (TPC) of permanent-magnet synchronous motors (PMSMs). The conventional TPC analyzes relationship among electrical torque, stator flux, voltage using magnitude vector PMSMs obtain angle reference accurately torque. In addition, stator-flux uses hysteresis method. However, that can be chosen in an inverter is limited because fixes vector, thus, large ripple generated low-speed region. proposed...

In this paper, a novel scheme for the estimation of equivalent series resistance (ESR) dc-link electrolytic capacitor in three-phase ac/dc pulsewidth-modulation converters is proposed condition monitoring. First, controlled ac current component injected into input. Then, it induces voltage ripples on dc output. By manipulating these and components with digital filters, value ESR can be calculated, where recursive least squares algorithm used reliable results. addition, corrected by...

In wind turbine generation (WTG) systems, a back-to-back converter with neutral-point-clamped (NPC) topology is widely used because this has more advantages than conventional two-level topology, particularly when operating at high power. There are 12 switches in the NPC topology. An open-switch fault rectifier of leads to distortion input current and torque vibration system. Additionally, an inverter causes output current. Furthermore, WTG system can break down worst case scenario. To...

This paper presents a new direct torque controlled space vector modulated method to improve the sensorless performance of matrix converter drives using parameter estimation scheme. The flux and error are geometrically combined in leakage make stator command voltage deadbeat manner. A estimating rotor speed, flux, resistance, resistance is derived verified with experimental results. Common terms dynamics utilized find simpler model involving some auxiliary variables. Using this model, state...

This paper proposes a neutral-point voltage balancing method for three-level inverter that uses discontinuous pulse width modulation (DPWM). The performance of system is affected by the unbalancing. Therefore, voltages series connected dc-link capacitors should be equal. Generally, offset added to reference in conventional method. However, when using DPWM, limitary because turn-on and turn-off switching occurs at regular intervals. proposed implemented adjusting pulsewidth positive negative...

This paper proposes a new modulation strategy that balances the neutral-point voltage for three-level neutral-clamped inverter systems. The proposed replaces P-type or N-type small switching states with other do not affect voltage. zero and medium are employed to help balancing. method little bit increases events output total harmonic distortion. However, this has strong balancing ability at all regions. Further, it is very simple implement in both space vector carrier-based PWM methods....

To increase the fault tolerance for cascaded H-bridge multilevel inverters (CHMIs) based on level-shifted pulse width modulation (LS-PWM), a modified LS-PWM method is proposed operating under faulty conditions. cover both open- and short-device cases, two types of switching scheme are included in this PWM method. With method, neutral shift can be applied as fault-tolerant control CHMIs LS-PWM. Finally, three-phase-balanced line-to-line voltages currents with minimum harmonic distortion...

Multilevel converter topologies are widely used in applications of wide-power range. The T-type topology, which is one many three-level topologies, has an advantage terms efficiency compared to the neutral-point-clamped (NPC) type. In using interest reliability been increased recently. Therefore, open-switch fault detection method and tolerance control for rectifiers, different from those inverters, necessary improve applications. When switches connected a neutral point occurs, NPC-type...

Conventional active-neutral-point-clamped (ANPC) inverters exhibit low voltage gain that inherently leads to a high dc-link requirement. An improved ANPC inverter is capable of generating five levels has recently reduced the twofold achieve unity gain. This led development single-stage dc-ac power converter with no frontend boost dc-dc converter. article proposes novel or boosted while higher levels. The first topology can provide 1.5 and extends number seven by incorporating only one...

The Vienna rectifier, which is a nongenerative-boost type used in many applications such as telecommunication systems and wind turbine systems. rectifier has special operating requirement. Many switching methods considering this requirement were proposed. These generally take into account the rectifier's operation with unity power factor because aims to provide load. However, for are diversified, control requirements have been suggested, including dc-link voltage balance novel under severely...

Vienna rectifiers, which are nongenerative-boost types of used in grid-connected applications with a unity power factor such as telecommunication systems and wind turbine systems. These rectifiers advantageous that they have low total harmonic distortion efficiency. There many switching methods, different from those threelevel topologies, for rectifiers. In this paper, we propose carrier-based discontinuous pulse width modulation (CB-DPWM) method. This method is simple compared to the PWM...

This paper proposes a power predictive control (PPC) method for three-phase pulse width modulated rectifiers without proportional-integral controller. The proposed PPC calculates the optimized voltage vector by analyzing relationship between virtual flux, active power, converter voltage, and filter parameters. Thus, an overshoot does not occur fast accurate becomes possible. algorithm computes error that would be produced applying each selects one contributes minimum error. simulation...

A new pulsewidth modulation (PWM) strategy which is an alternative approach of the discontinuous PWM (DPWM) for a three-level neutral-point-clamped (NPC) inverter proposed in this paper. NPC completely mature and very well-established topology high-power applications. However, has inheritance problem neutral-point voltage unbalancing due to split dc-link capacitors. This structure can cause large ripple. Furthermore, output currents are distorted by Therefore, must be controlled. In paper,...

This paper underpins the principles for generating reactive power in single-phase transformerless photovoltaic (PV) inverters. Two mainstream and widely adopted PV inverters are explored, i.e., H5 HERIC. With conventional modulation techniques, cannot be realized HERIC due to absence of freewheeling path negative region. Based on study, techniques proposed provide bidirectional current during period. technique, control is achieved inverters, without any modification converter structures. The...

Three-level topologies are widely used in back-to-back converters of wind turbine generation (WTG) systems. In comparison with a conventional two-level topology, three-level have more advantages, particularly for the high power. Neutral-point clamped (NPC) and T-type typical topologies. An open-switch fault rectifier that is connected to permanent-magnet synchronous generator (PMSG) leads current distortion torque vibration WTG Furthermore, systems can break down worst case. Therefore,...