Three-to-five-phase matrix converter using carrier-based PWM technique

<p><strong>Abstract</strong> - This paper proposes a simple Carrier-Based PWM (CBPWM) technique to control the three- to five-phase Direct Matrix Converter (3×5 DMC). The proposed technique uses the indirect modulation approach to control the 3×5 DMC such as a three-phase bidirectional rectifier followed by five-phase voltage source inverter (VSI). Based on this approach, it is possible to synthesize the desired five-phase output voltages with sinusoidal three-phase input currents and unity input power factor. A CBPWM method is suggested for each stage independently including both linear and overmodulation operating modes. By the proposed technique, in both operating modes, the maximum possible overall Voltage Transfer Ratio (VTR) are achieved. Moreover, this technique allows the input power factor to be controlled by controlling the input current displacement angle. The feasibility of the proposed technique has been verified by a series of simulation and experimental results based on Matlab/Simulink and dSPACE-DS1104 platform. The results show that, a sinusoidal output and input waveforms can be achieved with a maximum possible VTR in the linear region. However, in the overmodulation region, a maximum possible VTR is achieved at the cost of some distortion of output and input waveforms. Therefore, this technique can be used for the application where a higher VTR is essential.</p

Control and Modulation Techniques for the Three-to-Five Phase Indirect Matrix Converter

This thesis focuses on the development and practical assessment of novel modulation techniques for the three-to-five phase indirect matrix converter. The increasing popularity of five-phase systems necessitates power converter systems capable of interfacing with the three-phase grid and the use of the proposed indirect matrix converter facilitates this interface whilst eliminating the energy storage component in the dc-link. An indirect space vector PWM-based technique that performs zero-current switching at the rectifier stage is proposed and developed for the three-to-five phase indirect matrix converter. The technique controls the three-phase input power factor and ensures that a zero voltage vector is applied in the alpha2-beta2 vector space while generating the reference output voltage vector in the alpha1-beta1 vector space. A modified symmetrical switching sequence is proposed with single leg commutation. The modulation technique is then extended to simultaneously generate alpha1-beta1 and alpha2-beta2 voltage vectors. These techniques are experimentally validated for the three-to-five phase indirect matrix converter. Three novel overmodulation techniques to extend the voltage transfer ratio (VTR) are proposed and practically assessed. They enable the three-to-five phase indirect matrix converter to generate a higher output phase voltage, at the cost of generating a non-zero voltage vector in the alpha2-beta2 vector space. The superior of the three techniques adapts the ratio between the large and medium vectors based on the value of VTR and utilizes the dc-link ripple to reduce the voltage vector production in the alpha2-beta2 vector space. A control and modulation technique is proposed for reverse power flow allowing power from a five-phase source, in this thesis a permanent magnet machine, to inject power into the three-phase grid. The control technique operates the indirect matrix converter in a voltage boost mode thereby injecting power into the grid from a generator phase voltage that is lower than the grid phase voltage. A prototype three-to-five phase indirect matrix converter with a DSP and FPGA controller was designed and developed. Experimental results from this system verify the techniques and their benefits

AVERAGE-VALUE MODELING OF HYSTERESIS CURRENT CONTROL IN POWER ELECTRONICS

Hysteresis current control has been widely used in power electronics with the advantages of fast dynamic response under parameter, line and load variation and ensured stability. However, a main disadvantage of hysteresis current control is the uncertain and varying switching frequency which makes it difficult to form an average-value model. The changing switching frequency and unspecified switching duty cycle make conventional average-value models based on PWM control difficult to apply directly to converters that are controlled by hysteresis current control. In this work, a new method for average-value modeling of hysteresis current control in boost converters, three-phase inverters, and brushless dc motor drives is proposed. It incorporates a slew-rate limitation on the inductor current that occurs naturally in the circuit during large system transients. This new method is compared with existing methods in terms of simulation run time and rms error. The performance is evaluated based on a variety of scenarios, and the simulation results are compared with the results of detailed models. The simulation results show that the proposed model represents the detailed model well and is faster and more accurate than existing methods. The slew-rate limitation model of hysteresis current control accurately captures the salient detail of converter performance while maintaining the computational efficiency of average-value models. Validations in hardware are also presented

A Survey on Topologies and Controls of Z-Source Matrix Converter

This paper describes the Z-source matrix converter (ZS-MC) topology which specifically discusses topology and control on the ZS-MC. There are two topologies on the ZS-MC, namely Z-source direct-MC (ZS-DMC) and indirect-MC (ZS-IMC). The difference of each of these topologies is in the number of switching mosfets, where ZS-DMC put on nine switches, while ZS-IMC eighteen switches. ZS-IMC topology overcomes the limitations of traditional MC voltage reinforcement and accommodates the operation of buck and boost converter by reducing the number of switches and providing high efficiency

A Modified Carrier-Based Advanced Modulation Technique for Improved Switching Performance of Magnetic-Linked Medium-Voltage Converters

© 1972-2012 IEEE. The high-frequency magnetic link is gaining popularity due to its lightweight, small volume, and inherent voltage balancing capability. Those features can simplify the utilization of a multilevel converter (MLC) for the integration of renewable energy sources to the grid with compact size and exert economic feasibility. The modulation and control of the MLC are crucial issues, especially for grid-connected applications. To support the grid, the converter may need to operate in an overmodulation (OVM) region for short periods depending upon the loading conditions. This OVM operation of the converter causes increased harmonic losses and adverse effects on the overall system efficiency. On top of that, the size and cost of filtering circuitry become critical to eliminate the unwanted harmonics. In this regard, a modified OVM scheme with phase-disposed carriers for a grid-connected high-frequency magnetic-link-based cascaded H-bridge (CHB) MLC is proposed for the suppression of harmonics and the reduction of converter loss. Furthermore, with the proposed OVM technique, the voltage gain with the modulation index can be increased up to the range which is unlikely to be achieved using the classical ones. Extensive simulations are carried out with a 2.24 MVA permanent magnet synchronous generator based wind energy conversion system, which is connected to the 11 kV ac grid through a high-frequency magnetic-link and a five-level CHB MLC. A scaled down laboratory prototype is implemented to validate the performance of the converter

Improved output voltage quality using space vector modulation for multilevel inverters

Space vector modulation (SVM) has received wide acceptance due to many benefits over other techniques such as higher output voltages, lower total harmonic distortion (THD), high-efficiency and flexible to be implemented in vector control systems. In digital implementation, the SVM equations can be optimally computed by eliminate the use of complex forms. In this paper, the simple SVM based on twolevel inverter is employed for higher levels of inverters. This is to retain the simplicity of SVM computation for three-level and five-level cascaded H-bridge multilevel inverter (CHMI). Moreover, the proposed method utilizes two controller boards to perform high computational workloads and to eliminate glitch and error problems. Experiment results show that the THD of output voltage in five-level CHMI gives the smallest value among the results obtained from other levels

Improved Output Voltage Quality using Space Vector Modulation for Multilevel Inverters

Space vector modulation (SVM) has received wide acceptance due to many benefits over other techniques such as higher output voltages, lower total harmonic distortion (THD), high-efficiency and flexible to be implemented in vector control systems. In digital implementation, the SVM equations can be optimally computed by eliminate the use of complex forms. In this paper, the simple SVM based on two-level inverter is employed for higher levels of inverters. This is to retain the simplicity of SVM computation for three-level and five-level cascaded H-bridge multilevel inverter (CHMI). Moreover, the proposed method utilizes two controller boards to perform high computational workloads and to eliminate glitch and error problems. Experiment results show that the THD of output voltage in five-level CHMI gives the smallest value among the results obtained from other levels

POWER QUALITY CONTROL AND COMMON-MODE NOISE MITIGATION FOR INVERTERS IN ELECTRIC VEHICLES

Inverters are widely utilized in electric vehicle (EV) applications as a major voltage/current source for onboard battery chargers (OBC) and motor drive systems. The inverter performance is critical to the efficiency of EV system energy conversion and electronics system electro-magnetic interference (EMI) design. However, for AC systems, the bandwidth requirement is usually low compared with DC systems, and the control impact on the inverter differential-mode (DM) and common-mode (CM) performance are not well investigated. With the wide-band gap (WBG) device era, the switching capability of power electronics devices drastically improved. The DM/CM impact that was brought by the WBG device-based inverter becomes more serious and has not been completely understood. This thesis provides an in-depth analysis of on-board inverter control strategies and the corresponding DM/CM impact on the EV system. The OBC inverter control under vehicle-to-load (V2L) mode will be documented first. A virtual resistance damping method minimizes the nonlinear load harmonics, and a neutral balancing method regulates the unbalanced load impact through the fourth leg. In the motor drive system, a generalized CM voltage analytical model and a current ripple prediction model are built for understanding the system CM and DM stress with respect to different modulation methods, covering both 2-level and 3-level topologies. A novel CM EMI damping modulation scheme is proposed for 6-phase inverter applications. The performance comparison between the proposed methods and the conventional solution is carried out. Each topic is supported by the corresponding hardware platform and experimental validation

Advances in Converter Control and Innovative Exploitation of Additional Degrees of Freedom for Multiphase Machines

Multiphase variable-speed drives and generation systems (systems with more than three phases) have become one of the mainstream research areas during the last decade. The main driving forces are the specific applications, predominantly related to the green agenda, such as electric and hybrid electric vehicles, locomotive traction, ship propulsion, ‘more-electric’ aircraft, remote offshore wind farms for electric energy generation, and general high-power industrial applications. As a result, produced body of significant work is substantial, making it impossible to review all the major developments in a single paper. This paper therefore surveys the recent progress in two specific areas associated with multiphase systems, namely power electronic supply control and innovative ways of using the additional degrees of freedom in multiphase machines for various non-traditional purposes

Multiphase Machines and Drives-Revisited

Although the concept of a multiphase drive system dates back to the middle of the 20th century, the initial pace of development was rather slow, as witnessed by the first two surveys of the area published in the beginning of this century. However, considerably new developments have resulted in the last decade of the 20th century and the beginning of this century, leading to an authoritative survey of the asymmetrical six-phase drive control and subsequently of the review of the complete area. This also initiated the organization and subsequent publication of the first IEEE Transactions on Industrial Electronics "Special Section on Multiphase Machines and Drives" in May 2008, which commenced with another survey paper, and that contained 12 original research papers. Since the publication of this Special Section in May 2008, the level of interest and pace of developments in the area have further accelerated and substantial new knowledge has been generatedwith an ever-increasing number of published research papers and reported new industrial applications. Such a trend has been emphasized in a recent paper. It therefore seemed appropriate to revisit the area and organize this Special Section as a sequel to the first one. The call for the Special Section papers resulted in 51 submissions, almost twice as many as the total back in 2008, thus confirming a substantial growth of the area. Indeed, the amount of new knowledge acquired since the publication of the first Special Section in 2008 has meant that it was not possible to provide a complete and thorough survey of the field in a single review paper