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The dual-bridge matrix converter concept has been gaining recognition as a promising circuit alternative in recent years. A direct feed-forward unbalance control method with power factor adjustment ability is developed for a 9-switch dual-bridge matrix converter system. It firstly detects the line side source voltages. Then, after adjusting the swi...
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... unbalance control scheme has been studied thoroughly on a 9-switch dual-bridge matrix converter with three phase R-L load by both the simulation and experiment. Fig. 6 and fig. 7 illustrate the simulation result of the converter without and with the unbalance control method. Fig. 8 and fig. 9 demonstrate experimental results for the converter under same conditions. The waveforms shown in these figures are DC side voltage V dc and input/output currents. The following conclusions can be ...
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The three-phase AC-AC converter termed the matrix converter can provide high quality input/output waveforms and adjustable input power factor without any large energy storage component. However, it has not yet found much acceptance in industry. The main reason is that it requires a complicated commutation scheme to prevent input side short circuits...
Citations
... However, because matrix converter is a direct frequency conversion device without any energy storage components, the load side of it can be seriously affected by the distorted or unbalanced input voltages which can result in unwanted loworder harmonics in the input current and output voltages. These abnormal input behaviours deteriorate the working performances of the load.A phase shift is introduced between line currents and grid voltages due to the presence of input LC filter between grid and matrix converter, by which power factor decreases [12], [13]. As the power factor at the grid side decreases due to the presence of input LC fillter then the reactive power demand from the grid increases which causes increase in distribution and transmission power losses. ...
... In [21], a pridictive control technique is proposed to control the input and output variables. Several methods are also proposed in the literatures to get the unity power factor operation of matrix converter system under balanced grid voltages [12], [13]. A control method is proposed by Mahmoud Hamouds's paper [23] for the indirect matrix converter operating under unbalanced grid voltage. ...
... Various feedforward and feedback control are used to compensate these disturbances (Jussila & Tuusa, 2007). Feedforward control with the ISVM technique is utilised to counteract the input disturbances at the rectifier stage whereas the load side is controlled as a regular inverter in (Wei et al., 2003;Xu et al., 2007). Further, the singular value decomposition (SVD) method based on duty cycle space vector approach (Casadei et al., 2002;Hojabri et al., 2011) that represents the switch states independent of the variations of input voltages and output currents is incorporated with feedforward control in (Guan et al., 2019) by separately considering the system inputs and switch states of MC. ...
This article is focussed on developing a novel hybrid modulation technique for matrix converter. The concept of singular value decomposition (SVD) is utilised to synthesise the intermediate fictitious dc link voltage whereas generalised scalar pulse width modulation (GSPWM) is utilised to generate the target output voltage. SVD provides the required flexibility in selecting the switch states to improve the input power factor. In contrast, GSPWM helps in reducing the switching losses significantly by clamping the output voltage in synchronisation with the peak of the output currents. This proposed phenomenon reduces the switchings at high current which in turn, reduces the losses and improves the efficiency of the converter. The feedforward compensation used at the input side of the converter helps in achieving the balanced output currents for unbalanced input conditions. The simulation and experimental results with loss analysis render validation of the proposed technique.
... The feedforward method can be incorporated into the ISVM technique by modifying the switching functions of either the virtual rectifier or inverter to suppress the input disturbances [28][29][30][31][32][33][34]. This is analogous to the pulse width modulation algorithms for traditional back-to-back converters [24]. ...
... This is analogous to the pulse width modulation algorithms for traditional back-to-back converters [24]. In [28][29][30], the rectifier switching functions are regulated appropriately to eliminate the influence of the abnormal supply voltages and generate a constant (on averaged) DC-link voltage. The load side switching functions can then be selected in the same way as in a regular inverter. ...
... They together are the system inputs, while the output voltage space vector v o = v oα + jv oβ and the input current space vector i i = i iα + ji iβ are the system output variables. The existing modulation methods were derived based on the space vectors or similar quantities that are the products of switch states and systems inputs [14][15][16][24][25][26][27][28][29][30][31][32][33][34]. For example, in [24] the line-line voltage space vector can be defined by ...
Matrix converters can be sensitive to abnormal supply conditions due to the absence of energy storage elements. This sensitivity can get worse when the matrix converters are modulated by a traditional indirect space vector modulation that assumes the input variables are sinusoidal and balanced. Therefore, this study proposes a methodology for the modulation of matrix converters without requiring any assumption of the input voltages. The method uses a geometric representation based on the singular value decomposition of the switch states to synthesise the rotating vectors of the target duty‐cycle matrix. Furthermore, this study mathematically highlights the factors that regulate the amplitude of the output voltages and utilise them to compensate the adverse effect of the abnormal input voltages. Experimental results presented in this study validate that the proposed method can provide sinusoidal and balanced output currents in the presence of abnormal supply conditions.
... In the B2B converter, the input and output voltage boost can be realized with the aid of its large DC link electrolytic capacitor, although this may cause a premature failure despite its high energy density and relatively low price. To extend the lifetime of the converter, a foil capacitor can be used, especially when it is specifically meant to provide filtering rather than storing energy [14]. Regardless of the capacitor type used, the DC capacitor to a large extent demands that an additional sensor and control scheme should be incorporated for regulating its voltage, so as to avoid damage caused by voltage surge, and also to compensate for lower frequency ripples when smaller capacitance is used. ...
The matrix converter or pulse width modulated frequency changer, invented in the mid-1980s, is a direct power conversion device that can generate a variable voltage and frequency from a variable input source. Industrially, it is applied in adjustable speed control of induction motor drive, power quality conditioner, and traction applications. The aim of this paper is to evaluate the steady state characteristic behavior of an induction machine in terms of its speed and torque when driven by a three phase indirect matrix converter at reduced harmonics. Similarly, projecting an AC-AC matrix converter that ensures a uniform synchronization in frequency and voltage supplies between the three phase wound rotor machine and the transformer's grid voltage supply is discussed in the Scherbius scheme. The different methods of torque calculations pertaining to some selected machine circuit diagrams are presented for comparison and analysis. Emphasis on the torque-speed characteristics of the machine at varied resistance and slip values were graphically analyzed in MATLAB to determine the degree of torque-speed dependence on the rotor resistance and slip. The overall behavior of the machine under motoring, plugging, and regenerative modes was considered in this work, while a detailed Simulink modeling of an indirect matrix converter on the Scherbius drive scheme is also presented for further analysis.
... Therefore, Casadei et al. [9] introduced an improved control strategy, which imposed the input current vector along the vector subtraction (named u i1 in this letter) of the positive and negative voltage vector, rather than the vector addition (i.e., input voltage vector u i ). Numerical simulation and experimental results in [9]- [16] showed that the improved method could obtain sinusoidal input currents without affecting output performance. ...
... Casadei et al. [9]- [13] just proved the effectiveness of the improved strategy, but did not present the implementation. Sequence component separation is intuitively the most direct way to realize the method, as adopted by Kang et al. [14]- [16]. In [14]- [15], the common separation algorithm based on phase lock loop (PLL) and filters was adopted. ...
... Nevertheless, tuning parameters of the proportional-integral (PI) controller in PLL algorithm was complicated [17]. Wei et al. [16] applied the technique of delayed signal cancellation to separate sequence components. This technique is simple but requires relatively large storage space [18]. ...
When matrix converter works under unbalanced input voltages, sinusoidal input currents could be obtained if the input power factor angle in conventional control strategy is modified based on the positive and negative sequence components of input voltages. Some existing literature realized this goal by using sequence component separation, which was usually complicated and/or storage-consuming. Instead, a simple realization method is proposed by this letter to obtain sinusoidal input currents, which constructs the expected input power factor angle by filtering the square of input voltage vector with a notch filter. The proposed method is easy to implement, since no sequence extraction algorithm is required. Experimental results demonstrate that compared with the existing realization methods, the proposed method reduces the computation time and storage space with identical performance of improving input currents quality.
... Consequently, if the input voltages of the MC are subjected to any disturbance/imbalance, low-order harmonics are introduced in the output voltages and input currents of the converter. Furthermore, under unbalanced input voltage conditions, the maximum attainable balanced output voltages of the MC is reduced [1]–[3]. In the technical literature, a few methods have been proposed to mitigate the impacts of unbalanced input voltages on the performance of the MC [2]– [11]. ...
... In [7], the gain of the MC is calculated based on the instantaneous values of the input voltages and the duty cycles of the switches are calculated using the indirect Space Vector Modulation (SVM) strategy. In [9] and [3], a feed-forward method, based on the instantaneous measurement of the input voltages is proposed. References [1], [2], [8] improve the quality of the input currents under unbalanced conditions. ...
... Reference [8] proposes three methods to select the phase angle of the input current: (i) in the first method, the phase angle is calculated based on the positive and negative sequence components of the input voltages, (ii) in the second method, the input currents are chosen to be in phase with the input voltages, and (iii) in the third method, the input currents are chosen to be in phase with positive sequence of the input voltages. In all of the aforementioned methods, the maximum attainable voltage gain of the MC, which under ideal and balanced input voltage conditions is limited to 0.86, is further reduced [3], [11]. ...
Due to absence of a dc-link energy storage element in the direct matrix converter (MC), any abnormality/disturbance in the input voltages is directly reflected on the output voltages. In this paper, a new modulation strategy to control the 3$times$3 MC under unbalanced input voltage conditions is proposed. The proposed strategy is based on modification of the space vector modulation strategy, which formulates and solves an optimization problem to determine the best switching states and their corresponding optimal duty cycles, such that the errors in the output voltages and the input currents under unbalanced input voltage conditions are minimized. The salient feature of the proposed strategy is its capability to extend the output operating range of the MC. The proposed strategy ensures that optimal performance of the MC over the entire operating range, including the case when the converter operates with an output voltage greater than the maximum attainable balanced output voltage under unbalanced input voltage conditions, is achieved. Performance of the proposed strategy is evaluated and validated based on time-domain simulation studies in the MATLAB/Simulink software environment and experimentation on a scaled-down laboratory prototype.
... In this method, the matrix converter was described as virtual configuration of pulse with modulation (PWM) rectifier and inverter with "fictitious dc link. " The operational and technological research on MC were continued in different areas such as new topology of MC [10][11][12][13], input filter design [14,15], unbalance operational conditions [16][17][18], safe and practical commutation strategies [10,19], new control methods [20,21], new modulation methods [22,23], and new application such as hybrid vehicles [24]. Yoon and Sul (2006) [23] proposed new carrier based modulation methods for conventional matrix converter. ...
This study presents a new modulation method for multidirectional matrix converter (MDMC), based on the direct duty ratio pulse width modulation (DDPWM). In this study, a new structure of MDMC has been proposed to control the power flow direction through the stand-alone battery based system and hybrid vehicle. The modulation method acts based on the average voltage over one switching period concept. Therefore, in order to determine the duty ratio for each switch, the instantaneous input voltages are captured and compared with triangular waveform continuously. By selecting the proper switching pattern and changing the slope of the carriers, the sinusoidal input current can be synthesized with high power factor and desired output voltage. The proposed system increases the discharging time of the battery by injecting the power to the system from the generator and battery at the same time. Thus, it makes the battery life longer and saves more energy. This paper also derived necessary equation for proposed modulation method as well as detail of analysis and modulation algorithm. The theoretical and modulation concepts presented have been verified in MATLAB simulation.
... In comparison with the former one, the latter has been preferably investigated. Ref. [9], [10] adjusted only the rectifier switching function to counteract the unbalanced or distorted input voltages and maintain the local-averaged DC-link voltage constant. In contrast, merely the inverter modulation index is calibrated according to the varying DC-link voltage in [11]- [13]. ...
... All m d , Ū and V can be used to regulate and have the same effect on the amplitude of the output voltage space vector. It is important to note that when Ū is assumed to be constant, adjusting m d and V will lead to the same rectifier side compensation as in [9], [10]. Similarly, adjusting m d and Ū together with constant amplitude of V equals to the inverter side compensations in [11]- [13]. ...
Owing to the absence of intermediate energy storage elements, the outputs of matrix converters are influenced easily by abnormal input voltages. To this end, this paper proposes a generalized indirect space vector modulation with feedforward compensation capacity based on the space vector representation of the switch-state transfer matrices. To simplify the calculation of the modulation duty-cycle matrix, both the singular value decomposition and the space vector modulation techniques are used to render clear physical meanings to the modulation process, and to synthesize the desired variables without complex computations. Using this approach, the duty cycles for switch combinations can be calculated online to decouple the low order harmonics in the input side from the outputs. Besides, the geometrical perspective provided by this method makes the optimization on the switching sequence convenient. The simulation results verify the validity of the proposed method in maintaining the outputs sinusoidal and balanced disregarding the abnormal input voltages.
... Any supply disturbances deteriorate the quality of the output voltage and reduce the voltage transfer ratio. Different techniques to maintain the load voltage quality and maximum voltage transfer ratio have been investigated in the literature [4,5,6]. However, these techniques can provide a maximum of 86% voltage transfer. ...
The addition of Z-source components into the “source” of standard converters enables a boost functionality without the need for additional switch. This relatively recent conversion concept can be extended to the three-level two-stage matrix converter by inserting a single Z-source network into its intermediate dc-link. The topology formed is, therefore, physically not very different. However, its modulation is not very straightforward if advantages like voltage buck-boost flexibility, minimum commutation count, and sinusoidal supply and load quantities are to be achieved simultaneously. This paper presents the principles of operation and the modified space vector modulation strategy that can achieve the above-mentioned advantages of the three-level Z-source hybrid direct ac-ac power converter as an attractive topological alternative for ac-ac buck-boost energy conversion. The findings presented here have been verified in simulations while experimental validation is currently under development.
... Therefore, the more likely approach is to regulate the instantaneous powers to be constant and equal. Performing that requires modifications to the basic modulation scheme according to [36], [37]. Other than that the same control scheme as in Fig. 5 can be used to keep a constant source and hence grid-side instantaneous power. ...
Indirect matrix converter (IMC) is an alternative for ac/ac energy conversion, usually operated with a voltage stepped-down gain of only 0.866. For applications like distribution generation where voltage-boost functionality is required, the traditional style of operating the IMC is therefore not appropriate. Like most power converters, the operation of the IMC can surely be reversed to produce a boosted gain, but so far its relevant control principles have not been discussed. These challenges are now addressed in this paper with distributed generation suggested as a potential application. Simulation and experimental results for validating various performance aspects of the proposed control schemes can be found in a later section of this paper.
