Auxiliary Resonant Commutated Pole Inverter Research Articles

An Efficient Auxiliary Resonant Commutated Pole Inverter With Components Withstanding Low Voltage and Current

An efficient auxiliary resonant commutated pole inverter (ARCPI) is presented with the aim of enhancing the efficiency by the decrease of switching loss. The brief design method is that three sets of identical auxiliary circuits are arranged respectively on each bridge arm in order that switches can achieve soft-switching to reduce switching loss by the resonance among auxiliary devices. When the auxiliary circuit of each phase is involved in commutation process, the higher efficiency will be achieved on condition that the added loss of auxiliary circuits is lower than the reduced switching loss compared with the hard-switching inverter. The brief discusses every working state during a switching cycle. The main experimental results are as follows: Switches achieve soft-switching in a wide load range and the efficiency value of the novel ARCPI reaches 98.1% under the rated condition which is at least 0.3% more than that in other four comparison objects. Consequently, the presented inverter takes an advantage in efficiency over other similar soft-switching inverters.

Derivation of Resonant Period for Soft Switching Considering Nonlinear Characteristics of Output Capacitance in Switching Device

Many soft switching techniques utilize a resonance between an inductor and parasitic output capacitors of switching devices. However, output capacitance has nonlinear characteristics, which obscures the resonant period for soft switching. In this paper, a new method is proposed to derive the resonant period by considering nonlinear characteristics of the output capacitance. The method can be applied to a bridge-type converter which utilizes resonance for soft switching. Other parasitic capacitances which affect the resonant period, are also considered. To verify the proposed method, simulations and experiments were performed with a 3-kVA prototype half bridge auxiliary resonant commutated pole inverter.

An Improved Auxiliary Resonant Commutated Pole Inverter With Low Loss of Energy Recovery

This brief proposes an improved auxiliary resonant commutated pole inverter (ARCPI) to optimize the transmission efficiency of the inverter. During the commutation process of the inverter, main switches can acquire zero-voltage switching and auxiliary switches can acquire zero-current switching, bringing about the significant reduction of switching loss. Besides, when the resonant state suspends in each switching cycle, the surplus energy in the resonant inductor will be fed back to the energy-storage capacitor through only one auxiliary diode, making for low loss of energy recovery. This brief illustrates each working state in a switching cycle. The relative experimental waveform indicates that switches acquire soft-switching. The efficiency of the proposed inverter achieves 99.1% at rated output power. Thus, the proposed inverter can have efficiency superiority over other similar inverters.

Research on auxiliary resonant commutated pole inverter for driving brushless DC motor

The brushless DC motor is generally used in small satellite flywheel systems due to its good control performance and structure robustness. However, its driving inverter still suffers from hard-switching that leads to higher loss and larger heatsink requirement. The resulting low power density and EMI problems have been a great challenge for the space satellite applications. This paper describes a novel auxiliary resonant commutated pole inverter (ARCPI) for driving the brushless DC motor. An inserted inductor is controlled to resonant with the buffer capacitor of the inverter’s lower arm switches; a resonant capacitor is paralleled with the inductor branch as well. Zero-current switching and zero-voltage switching conditions are therefore realized for the switches of the entire circuit. The reverse recovery problem of diodes are also avoided by zero current turning-off. The working states of the proposed novel ARCPI inverter are analyzed and the mathematical model for every state is established. Furthermore, the parameter design is discussed to provide soft-switching conditions. Finally, the proposed ARCPI inverter is applied for driving a brushless DC motor. A voltage/current double closed control loop is designed for the motor controller and the system simulation setup is built. The simulation results prove that soft-switching operation is realized for all of the switches; the proposed inverter is effective for driving brushless DC motors. Besides, the motor current fluctuation decreases by 45.7%. The motor torque and the motor speed present with good control performance as well.

Mitigation of Motor Overvoltage in SiC-Based Drives Using Soft-Switching Voltage Slew-Rate ($dv/dt$) Profiling

In silicon carbide (SiC) device based motor drives, the high-voltage slew-rate ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dv</i> / <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dt</i> ) associated with the fast-switching transitions results in excessive motor overvoltage, due to the reflected wave phenomenon, which increases the motor winding insulation stress and causes premature failure while raising electromagnetic interference (EMI) problems. This article proposes a soft-switching voltage slew-rate profiling approach to mitigate the motor overvoltage in SiC-based cable-fed drives. The proposed approach optimizes the rise/fall time of the output voltage according to the cable length, without altering the switching speed of the SiC devices. Since increasing the switching rise/fall time using conventional approaches, such as increasing the gate resistance, results in an increased switching power loss, the proposed profiling approach is implemented using a soft-switching inverter. The optimum rise/fall time that can significantly mitigate the overvoltage is derived using frequency- and time-domain analysis. The auxiliary resonant commutated pole inverter (ARCPI) is adopted as an example of the soft-switching inverter to experimentally verify the proposed slew-rate profiling approach for the overvoltage mitigation. The analysis and experimental results show that the motor overvoltage is fully mitigated when the output voltage rise/fall time is set as the cable antiresonance period, i.e., four times of the wave transmission time along the cable. Furthermore, the slew-rate profiling approach along with the ARCPI reduces the switching loss and improves the EMI performance at the high-frequency region, compared with the conventional hard-switching converter. Specifically, the maximum efficiency of the ARCPI is about 99%.

A Synchronous Auxiliary Resonant Commutated Pole Soft-Switching Inverter With Improved Load Adaptability

To realize a soft-switching inverter with small volume and high efficiency, a synchronous auxiliary resonant commutated pole (SARCP) soft-switching inverter with improved load adaptability is proposed, which only contains two auxiliary inductors. In one switching cycle, all commutation processes can be synchronously assisted by an auxiliary inductor. Soft switching is achievable for all switches of the SARCP inverter. Compared with the auxiliary resonant commutated pole (ARCP) inverter, the SARCP inverter has improved load adaptability, especially in the light load current condition, which is beneficial to reduce the total power loss and the dc-link capacitance. The equivalent circuits of the SARCP inverter are given under different operation modes. The operation principle, soft-switching implementation conditions, parameter optimization design methods, and the characteristics of the SARCP inverter are analyzed. Finally, simulation and experimental results verify the effectiveness of the SARCP inverter.

Hybrid SVPWM Modulation Strategy for Auxiliary Resonant Commutated Pole Inverter

Although the auxiliary resonant commutated pole inverter (ARCPI) can achieve soft-switching for main switches, the auxiliary commutation circuit (ACC) itself has a loss, especially under high frequency. To reduce the loss of ACC and optimize the efficiency of the ARCPI, this article proposes a hybrid space vector pulsewidth modulation (SVPWM) strategy. It can not only compensate for the influence of dead time but also reduce the operation times of the ACCs. First, the operation principles of an ARCPI are briefly analyzed. The topology can achieve soft-switching reliably for all switches with simplified ACCs. Then, appropriate zero vectors are designed for the hybrid SVPWM modulation strategy, which can guarantee that unnecessary switching actions are eliminated, and the switches in each bridge leg conduct symmetrically. Furthermore, the trigger pulse generation method for ACCs based on only one main switch is designed. Finally, the simulation and experimental results are given to demonstrate the validity of the proposed strategy.

Experimental Evaluation of SiC Mosfets in Comparison to Si IGBTs in a Soft-Switching Converter

Silicon-carbide (SiC) mosfet s have shown superior characteristics to Si IGBTs, bringing in significant performance improvement such as enabling more compact, higher efficiency converters that are not feasible with conventional Si IGBTs. Currently, there is a lack of systematic and conclusive investigation into soft-switching inverters using SiC mosfet s in comparison to Si IGBTs. This article, therefore, presents a comparative evaluation of a soft-switching inverter, i.e., the auxiliary resonant commutated pole inverter (ARCPI) using SiC mosfet s or Si IGBTs. The switching transition, switching device current stress, neutral point ripple current, electromagnetic interference (EMI), efficiency, and cost are compared on identical ARCPI setups, i.e., with the same printed circuit boards and under identical driving conditions (gate drivers). Experimental results show that the ARCPI using SiC mosfet s has better performance than that using Si IGBTs due to its faster switching speed. First, the ARCPI using SiC mosfet s performs full zero-voltage switching and the switching transition behavior is more predictable. Unlike Si IGBTs, SiC mosfet s have no turn- off tail current and forward voltage drop during switching transitions. Second, the ARCPI using SiC mosfet s endures less current stress and smaller ripple current in dc-link capacitors. Third, the ARCPI using SiC mosfet s exhibits better EMI performance and higher efficiency. Specifically, a maximum 20 dB μ V harmonic reduction can be achieved around 800 kHz and a 3.1% improvement in efficiency can be achieved at 6 kW.

Modified Double Auxiliary Resonant Commutated Pole Inverter and its Modulation Strategy

In order to overcome the complexity of the double auxiliary commutation circuit (DACC) and the coupling of the resonance process of the double auxiliary resonant commutated pole (DARCP) inverter, a modified DARCP inverter topology and its modulation strategy are proposed. The modified topology not only retains the advantage of reliable zero voltage switching (ZVS) turn-off of auxiliary switches and so on, but also realizes the simplification of the DACC and the decoupling of the resonance process. The cost of the inverter and the system oscillation caused by coupling resonance are reduced, and the performance and practicability of the inverter are improved. According to the equivalent circuits of different operation modes under the proposed modulation strategy, the operation principle, the soft-switching implementation condition, and the parameter design method are analyzed. Finally, a 10-kW, 16-kHz soft-switching inverter prototype is built. Experimental results are given to demonstrate the validity of the proposed inverter.

Methods for Suppressing Spike Voltage of ARCPI Auxiliary Switch

The Auxiliary Resonant Commutated Pole Inverter which is a kind three phase soft inverter. It is very suitable for AC driving. During the developing process, the spike voltage was produced between the auxiliary switch. Research shows that the diode in the auxiliary resonant circuit has a reverse-recovery phenomenon. Aim at this phenomenon, the methods of using clamping diode, double RCD snubber and saturable inductance are adopted. Experiments approve that all the methods can suppress the spike voltage between the auxiliary switch effectively. The method using saturable inductance has the advantage of simple circuit , low power-loss and low effect on ARCPI.

Three‐phase double auxiliary resonant commutated pole inverter topology and analysis of its working principle

This study presents a double auxiliary resonant commutated pole (ARCP) inverter topology and modulation strategy. In the proposed inverter, the zero-voltage-switching (ZVS) turn-off of auxiliary switches influenced by parasitic circuit elements from the wiring process can be avoided. It is assured that the auxiliary switches achieve ZVS turn-off reliably. Hence, the reliability of the ARCP inverter is improved, especially in high-power application. According to the equivalent circuits in different operation modes under the proposed modulation strategy, the working principle, soft-switching implementation condition, and parameter design procedure of the proposed inverter are analysed successively in this study. Finally, a 10 kW, 16 kHz double ARCP inverter prototype is built. Experimental results are given to demonstrate the validity of the proposed inverter.

Advanced control and design methods of the auxiliary resonant commutated pole inverter

Abstract This paper presents several methods that enable the reduction of power loss in the auxiliary resonant commutated pole inverter - ARCP. Presented methods can be divided into static and dynamic ones. The static methods are related to an appropriate design of the inverter, whereas dynamic ones to advanced control of the power transistors. A variety of design and control methods are presented together with their advantages and disadvantages. The new control method of the current in the resonant branch is described. The main benefits of the proposed extended control method and their constrains are shown

Research on A Novel Modulation Strategy for Double Auxiliary Resonant Commutated Pole Soft-switching Inverter with the Shunt Dead Time

Aimed at the problem that the auxiliary commutation circuit (ACC) of auxiliary resonant commutated pole (ARCP) inverters has a high loss in commutation processes, this paper presents a novel modulation strategy with shunt dead time based on a double ARCP (DARCP) inverter. In comparison with the original modulation strategy, this modulation strategy cannot only achieve soft switching for all switches, but also avoid the superposition of resonance current and load current at commutation moments in double ACCs (DACCs) and make the maximum current through DACCs approximately equal to load current in commutation processes. So, the circulating current loss in DACCs and the current stress of auxiliary switches can be effectively reduced. According to the equivalent circuits in different operation modes under the novel modulation strategy, this paper analyzes the operation principle, soft-switching implementation condition, and optimal parameter design procedure of the DARCP inverter. Finally, a 10-kW–16-kHz DARCP inverter prototype with insulated gate bipolar transistor-based switches is built. Experimental results are given to demonstrate the validity and features of the DARCP inverter under the novel modulation strategy.

Research on a Novel Modulation Strategy for Auxiliary Resonant Commutated Pole Inverter With the Smallest Loss in Auxiliary Commutation Circuits

Aiming at overcoming the problem that the auxiliary commutation circuit (ACC) of auxiliary resonant commutated pole (ARCP) inverters has a high loss in commutation processes, this paper presents a novel modulation strategy based on an improved ARCP inverter. In comparison with the original modulation strategy, this modulation strategy can not only realize soft-switching for all switches, but also avoid the superposition of resonance current and load current at commutation moments in ACCs and make the maximum current through ACCs approximately equal to load current in commutation processes. So the circulating current loss in ACCs and the current peak stress of auxiliary switches can be effectively reduced. According to the equivalent circuit in different operation modes under this modulation strategy, this paper analyses the operation principle, soft-switching implementation condition, and optimal parameter design procedure of the improved ARCP inverter. Finally, the novel modulation strategy is applied to a 10 kW 16 kHz improved ARCP inverter prototype with insulated gate bipolar transistor-based switches. Experimental results are given to demonstrate the validity and features of the inverter under the novel modulation strategy.

Characterization and Comparison of High Blocking Voltage IGBTs and IEGTs Under Hard- and Soft-Switching Conditions

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> The market of converters connected to transmission lines continues to require insulated gate bipolar transistors (IGBTs) with higher blocking voltages to reduce the number of IGBTs connected in series in high-voltage converters. To cope with these demands, semiconductor manufactures have developed several technologies. Nowadays, IGBTs up to 6.5-kV blocking voltage and IEGTs up to 4.5-kV blocking voltage are on the market. However, these IGBTs and injection-enhanced gate transistors (IEGTs) still have very high switching losses compared to low-voltage devices, leading to a realistic switching frequency of up to 1 kHz. To reduce switching losses in high-power applications, the auxiliary resonant commutated pole inverter (ARCPI) is a possible alternative. In this paper, switching losses and on-state voltages of NPT-IGBT (3.3 kV-1200 A), FS-IGBT (6.5 kV-600 A), SPT-IGBT (2.5 kV-1200 A, 3.3 kV-1200 A and 6.5 kV-600 A) and IEGT (3.3 kV-1200 A) are measured under hard-switching and zero-voltage switching (ZVS) conditions. The aim of this selection is to evaluate the impact of ZVS on various devices of the same voltage ranges. In addition, the difference in ZVS effects among the devices with various blocking voltage levels is evaluated. </para>

Switching faults and safe control of an ARCP multicell flying capacitor inverter

The auxiliary resonant commutated pole (ARCP) multicell converter is a soft-switched variant of the multicell converter. It is shown in this paper that the ARCP technique can be very efficiently used in multicell flying capacitor converters. The main properties of the resulting soft switching multicell converter are very similar to those of the hard-switched version. They are presented and validated by simulations as well as experimental results. In practice, due to the damping, the ARCP multicell converter can suffer from switching faults as in two-level ARCP inverters, but in the case of a multicell converter failures can occur in different cells. So, the main control strategies are evaluated and the switching process is discussed step by step, taking account of the main imperfections of actual control circuits. When they can occur, the switching faults are described and analyzed. Finally, an original quasisoft switching control that should give a high safety of operation is proposed. Experimental results obtained with a 900 V-100 A ARCP multicell inverter leg are given and the performances are compared with those of a hard-switched multicell inverter leg of the same rating.

ARCPI resonant snubber for the neutral-point-clamped inverter

This paper reports a resonant snubber for the neutral-point-clamped (NPC) inverter using the auxiliary resonant commutated pole inverter (ARCPI) technique. The proposal guarantees zero-voltage switching of the main switches and zero-current switching of the auxiliary switches without incurring any voltage or current spikes across or through the main switches and without being subjected to any modulation constraints. The operation principle of the ARCPI NPC inverter is illustrated. A simple method dealing with the static overvoltage problem of the inner switches is described. Commutation durations and current stresses in the basic ARCPI circuit are analyzed. The results enable mathematical understanding and practical designing of the basic ARCPI circuit. In particular, the self-balancing quality and controlling possibility of the DC center potential in the basic ARCPI circuit are investigated. The proposal is verified by a 3 kW half-bridge ARCPI NPC inverter laboratory prototype.

Analysis, designing, and experimentation of a transformer-assisted PWM zero-voltage switching pole inverter

This paper proposes a transformer-assisted pulsewidth modulation (PWM) zero-voltage switching pole inverter. As the auxiliary-resonant-commutated pole inverter (ARCPI), the proposal guarantees zero-voltage switching of the main switch and zero-current switching of the auxiliary switch, with a small power auxiliary circuit and full PWM capability. In particular, problems outstanding with the ARCPI such as control complexity, auxiliary switch protection, and center-tap potential variation, etc., are solved in the proposal. The commutation process is discussed step by step in the paper. A detailed analysis for the auxiliary circuit with regard to commutation duration/duty-cycle limitation, auxiliary switch peak current/RMS current, resonant capacitor RMS current, as well as pole output voltage loss are presented afterwards. A design methodology for the auxiliary circuit is recommended based on the analysis. The proposal is experimentally verified with a 4.25 kW half-bridge inverter prototype.

Auxiliary resonant commutated pole inverter using two internal voltage-points of DC source

This paper presents a new auxiliary resonant commutated pole inverter that has series-connected batteries as the DC source. This inverter has two main switches and two auxiliary switches, and of all these devices achieve soft switching. The resonant operations are employed only during the commutating intervals; therefore, pulsewidth modulation (PWM) can be applied to the circuit. This circuit has the feature of using two internal voltage points of the DC source. Consequently, the circuit has the advantages of stability, simplicity in control, and high efficiency. The principle of the circuit operation and the experimental results are described in this paper.

The Loss Minimizing Condition of the Auxiliary Resonant Commutated Pole PWM Inverter and its Practical Problem

In order to improve the control performance and to make main circuit components small, high frequency switching strategy is applied to PWM inverters. On the other hand, switching loss on the switching devices tends to increase as the switching frequency goes high. To prevent the increase of switching loss, many kinds of resonant type inverter topologies have been proposed. It is called that an auxiliary resonant commutated pole (ARCP) inverter is one of the most suitable topology for PWM control and low switching loss operation. On the other hand, it is reported that efficiency of the ARCP inverter does not so high compared with that of the conventional so-called hard switching inverters on the practical applications. These discussion will be concluded if the theoretical loss estimation of the ARCP inverter is reported.In this paper, a theoretical loss calculation method and a optimum circuit parameter condition for the ARCP PWM inverter is proposed. It is clarified that the efficiency on the optimum circuit parameter condition will rather be increased but it is difficult to use the parameter in the practical application. Then, the modified parameter that is applicable to the practical circuit is obtained. Unfortunately, even on the modified condition, the resultant efficiency does not extremely high compared with that of the conventional hard switching inverter. These results are coincide well with the experimental results on the bread board set-up and the up to present efficiency which are reported on the practical application. By the way, ARCP inverters are going to recognized as the suitable strategies for reducing EMI noise. Then, the proposed loss estimation method and the practical parameter calculation method will be useful for designing the ARCP inverter with low EMI and high efficiency.