ABSTRACT The working principle of the matrix converter has been described by many authors in vari... more ABSTRACT The working principle of the matrix converter has been described by many authors in various ways. Especially, the introduction of the virtual DC link concept was one of the most important milestones in the matrix converter theory. However, the mathematical description is not symmetrical in this case. That is why a new approach presented in this article strives to symmetrize the matrix converter voltage and current transfer functions. For this purpose, new term is defined: DC-space vector.
The direct torque control (DTC) strategy is one of the most performance methods for induction mac... more The direct torque control (DTC) strategy is one of the most performance methods for induction machine (IM) drive torque control. The controlled stator magnetic flux and torque cannot be easily measured and therefore must be calculated using an IM mathematical model. This paper examines the impact of the replacement the original voltage IM model by Luenberger observer on the drive performance. As the original model requires only voltage and current, the observer is implemented in such a way that the same input variables can be used. The models are created and tests are carried out experimentally employing the dSPACE platform on induction motor of power 5.5 kW. The experimental results indicate better performance of the control strategy based on Luenberger observer.
Similarly as in field of combustion engines the efficiency map is very convenient tool for compar... more Similarly as in field of combustion engines the efficiency map is very convenient tool for comparison of different motor variants. The overall efficiency of the induction machine can be analyzed in this way too. It is well known, that behavior of the induction machine can be easily described by its state space model. However, this description is mostly used in order to analyze the dynamic behavior only. The efficiency of the machine remains mostly out of the scope of the published articles. Moreover, the rotor resistance can change significantly depending on the mode of operation of the induction motor and power loss caused by hysteresis and eddy currents is not included into the consideration at all. Therefore this paper strives first to derive analytically the efficiency of the induction machine and thus prepare the comparison basis for the future impact analysis of changing the machine parameters and respecting the power loss in magnetic yoke.
The paper deals with development of the induction motor drive direct torque control (DTC) based o... more The paper deals with development of the induction motor drive direct torque control (DTC) based on the next step voltage vector prediction. The principle of the method is explained and the system mathematical description is provided. The derived control algorithm is implemented both in the simulation software MatLab/Simulink and on the real induction motor drive with dSPACE control system. Simulated and measured results in steady states and transients are presented.
Sophisticated control of induction motor drive requires knowledge of the rotor angular velocity. ... more Sophisticated control of induction motor drive requires knowledge of the rotor angular velocity. In order to obtain the speed information an optical sensor is usually utilized. However, it is not always advantageous because of the whole drive robustness decrease caused by the speed sensor inclusion. The paper presents some simulation and measurement results in case of the MRAS (Model Reference Adaptive System) method employing in attempt to eliminate the induction motor drive speed sensor. The operation principle is explained and a mathematical model of the drive system is created. The MRAS method influence on the drive behaviour is examined in simulation environment and experimentally. Finally, the experimental results and comparison of the drive behaviour with and without the speed sensor are discussed.
ABSTRACT This paper examines the problem of adequacy in induction machine modeling and attempts t... more ABSTRACT This paper examines the problem of adequacy in induction machine modeling and attempts to provide a firmer basis for the selection of an appropriate model, to find a possible connection between the two most widespread models and to confirm or disprove their equivalence or differentness as the case may be.
Purpose. Creating a three-dimensional mathematical model of the electromagnetic field of an auger... more Purpose. Creating a three-dimensional mathematical model of the electromagnetic field of an auger electromechanical converter with the external solid rotor, taking into account the geometry peculiarities and the finite length factor. Methods. Calculation of the electromagnetic field distribution has been performed with the use of the computational solving the differential equations by the finite element method in a three-dimensional statement. Findings. It has been set that in the air gap the values of magnetic induction vary in the range of 0.7 -0.8 T, in the flanks of the stator teeth they reach the value of 2 T. Induction in a hollow ferromagnetic rotor varies mainly in the range of 1.3 -2.0 T, and in a thin layer with a thickness of 1.0 -1.5 mm, facing the stator surface, it reaches the value of 2.3 T. Within one pole pitch, the z-component maximum of the eddy currents density is 18ꞏ10 6 A/m 2 on the inner hollow rotor surface. It has been determined that, with the exception of the 'edge' rotor sections, where the transverse component of eddy currents prevails, as well as the sections of the magnetic flux "input" into the rotor, the eddy currents are mainly axial. A comparison of the results of measuring the electric field intensity on the rotor surface evidences a data difference of not more than 4%. The proposed model enables to optimize the design of the converter, in particular, to reduce the magnetic induction in the stator teeth. Originality. Numerical results have been obtained in the form of spatial patterns of distribution and graphical dependences that take into complete account the axial and tangential components of the electromagnetic field. The considered finite element model can be used when analysing the electromagnetic fields in electromechanical converters with a complex secondary part. This will give a possibility to consider the real threedimensional field character, caused by the design peculiarities and the final axial dimensions.
The authors propose new modiflcation of the direct torque control method based on voltage vector ... more The authors propose new modiflcation of the direct torque control method based on voltage vector prediction. The principle of the method is explained and the mathematical description of the system is provided. The control algorithm is implemented in simulation envi- ronment MatLab/Simulink and its behaviour is tested on the mathematical model of an induction motor drive. Then, the control algorithm is verifled on the real drive with induction motor with dSPACE control system. The results from the simulations and measurements are presented and compared with those when using the fundamental direct torque control method. 1. INTRODUCTION In 1986 Isao Takahashi and Toshihiko Noguchi presented a new control strategy of induction mo- tor control algorithm called direct torque control (DTC) (1). The method is based on transistor switching according to table uses hysteresis torque and magnetic ∞ux controllers. One of the dis- advantages is the relatively high torque ripple. A lot of modiflcations were performed since then. The most important are DTC with space vector modulation (2), multilevel inverter application (3) and predictive algorithms of DTC (4,5). The method described in the paper presents another modiflcation using prediction of voltage vector. It is based on the calculations of changes in stator and rotor magnetic ∞uxes and motor parameters. 2. PRINCIPLE OF VOLTAGE VECTOR PREDICTIVE DTC The basic theory of the proposed method flrstly predicts the stator magnetic ∞ux for the next cycle and then the voltage vector that should be switched on the inverter. The calculations are based on the every cycle motor state values (measured or estimated), motor parameters and reference values. Because the requirement of the method is the rotor ∞ux value knowledge, the estimator have to calculate with adequate precision and parameters of the induction machine must be known. The block diagram of the controlled system is depicted in Fig. 1 on the left hand side. The calculation of voltage for the next cycle is based on the induction motor stator voltage Equation (1). After discretisation it results in (2)
2014 International Conference on Applied Electronics, 2014
This paper describes a embedded controller for the matrix converter. Thanks to its computing thro... more This paper describes a embedded controller for the matrix converter. Thanks to its computing throughput it is suitable for university use, but it enables operation in the whole industrial rage thank to its construction. Besides the example usage in matrix converter, the control system is generally usable for various control tasks.
In this paper, the implementation of the Field Oriented Control and the Direct Torque Control in ... more In this paper, the implementation of the Field Oriented Control and the Direct Torque Control in matrix converter supplied induction motor drives is analysed, and compared with the implementation in drives supplied by the Voltage Source Inverter. The analysis is accompanied by the results of numerical simulations and experimental implementations of these two control methods.
The presented paper deals with matrix converters pulse width modulation strategies design with em... more The presented paper deals with matrix converters pulse width modulation strategies design with emphasis on the electromagnetic compatibility. The most of the contemporary modulation strategies are able to provide practically sinusoidal waveforms of the input and output currents with negligible low order harmonics, and to control the input displacement factor. A special digital control system was developed for the realized experimental test bed which makes it possible to achieve greater throughput of the digital control system and its variability.
The authors propose to work out common principles of synthesis of electromagnetic fleld models fo... more The authors propose to work out common principles of synthesis of electromagnetic fleld models for the main types of electrical machines. The main objective is to create fleld models of electric machines by inheritance of their characters from the original Maxwell's equations. An inverse problem is being also solved | the synthesis of electric machine electromagnetic fleld equations using object-oriented design. Object-oriented design (OOD) implements the idea of solving problems using models based on the concepts of the real world. Fundamental element is an object that combines the data structure (parameters) to the behaviour (calculating procedures). Philosophy of knowledge representation in the form of objects of prisoners in their data and procedures developed by G. Booch, but so far only been applied in the fleld of software development, as well as an ideological foundation of programming languages such as Java, C++, C#, Visual Basic, Delphi (1). Consideration of OOD princi...
2020 21st International Scientific Conference on Electric Power Engineering (EPE)
This work deals with a real-time optimum flux search control (SC). The method is integrated into ... more This work deals with a real-time optimum flux search control (SC). The method is integrated into Predictive Torque Control (PTC) of induction motor drive (IMD). The proposed predictive search control searches the optimum stator flux amplitude, at which the current amplitude is the lowest. The output of the SC is used as a reference for the PTC controller. As the control variable of the proposed SC, the predicted stator current vector amplitude is utilized. The method was verified experimentally on a laboratory drive with a 5.5 kW induction motor. The IMD achieves a current minimization while maintains the working point defined by the speed and load. The experiment shows good results during steady-state and sufficient performance during transients.
2019 International Conference on Electrical Drives & Power Electronics (EDPE)
Three methods of cooling gallium nitride (GaN) transistors have been tested and directly compared... more Three methods of cooling gallium nitride (GaN) transistors have been tested and directly compared together. Under similar conditions, top side cooled GaN was compared to the bottom side cooled type; both were of the same electrical parameters and were mounted on FR4 (fibreglass resin) and IMS (insulated metal substrate) printed circuit boards. At equal dissipated power the proposed bottom side cooled transistor on IMS board reaches half the temperature compared to the top side cooled one and one fourth of the temperature compared to the bottom side cooled GaN on FR4 board. A High speed driver is placed close to the transistor also on the IMS board to reduce parasitic inductance of the gate driving path from control board to the high power side on the IMS board.
2017 18th International Scientific Conference on Electric Power Engineering (EPE)
Direct torque control (DTC) is one of the best performing strategies for induction motor control ... more Direct torque control (DTC) is one of the best performing strategies for induction motor control in many applications. However, this method suffers from a few disadvantages. Very important one is the presence of ripples in the torque waveform. The main reason of their presence is the inaccurate model of the motor. This paper utilizes Luenberger observer to calculate the model of the motor instead of the classical one. The DTC strategies with its original model and with Luenberger observer are created on dSPACE ds1103 platform. The results from experiment on a specific induction motor drive are shown. The paper shows better performance of the DTC with model based on Luenberger observer. The ripples in torque waveforms were lowered while switching frequency of the transistors remained the same.
Modernization consists of a new compact drive unit for the Citröen Berlingo Electrique electric v... more Modernization consists of a new compact drive unit for the Citröen Berlingo Electrique electric vehicle. The drive unit integrates a power converter for the traction motor, a DC/DC low voltage converter, an on board charger and an electronic control unit (ECU). The new aircooled power converter is lightweight and more efficient due to a modern equipment used. The new ECU uses controller area network (CAN) to communicate with the power converters and also collects all the measured data that can be transferred in real-time during drive. This vehicle also currently provides a test and measurement platform for Master's Degree students.
Matrix converter belongs to direct frequency conver ter category. Output voltage is made by direc... more Matrix converter belongs to direct frequency conver ter category. Output voltage is made by direct swit ching of input phases to output phases. This fact means t hat converter does not need DC-link capacitor which in reases the costs and volume requirements of the converter. The absence of DC-link capacitor is one of the mai n advantages of the matrix converter. On the other ha nd it means that the output voltage amplitude is li mited by 86.6% of the input voltage amplitude. Higher vol tages can be achieved with overmodulation, which ca uses input current distortion. The other advantages of t he converter compared to conventional indirect freq uency converter are: power factor regulation, operation i n all four quadrants, its high dynamic, sinusoidal current consumption, nearly sinusoidal output voltage wavef orm with low harmonic content, and high efficiency. To the main disadvantages belongs: amount of semiconductor devices, limited output voltage amplitude, and complicated contro...
Inductive power transfer (IPT) applications, such as stationary charging of electric vehicles (EV... more Inductive power transfer (IPT) applications, such as stationary charging of electric vehicles (EVs), at least moderate coupling between the coils to achieve high efficiency, but the coefficient k typically varies between of 0.1 to 0.4, depending on the displacement of the coils according to SAE J2954. Thus, accurate and reliable methods for estimation of k are required for positioning of the EV to achieve optimal alignment with the charging pad. Additionally, in IPT, numerous control strategies are available for regulating output power and optimizing system efficiency that require an accurate estimate of the mutual inductance or k. However, existing estimation methods tend to require detailed a-priori information of a large number of circuit parameters, or they need measurement of currents or voltages in both primary and secondary sides. This paper presents a preliminary evaluation of a novel, primary-side method to estimate k, which is based solely on the frequency response of the ...
Gallium nitride (GaN) devices are becoming more popular in power semiconductor converters. Due to... more Gallium nitride (GaN) devices are becoming more popular in power semiconductor converters. Due to the absence of the freewheeling substrate diode, the reverse conduction region is used in GaN transistors to conduct the freewheeling current. However, the voltage drop across the device in the reverse conduction mode is relatively high, causing additional power losses. These losses can be optimized by adequately adjusting the dead-time issued by the microcontroller. The dead-time loss minimization strategies presented in the literature have the common disadvantage that either additional hardware or specific converter data are needed for their proper operation. Therefore, this paper’s motivation is to present a novel dead-time loss minimization method for GaN-based high-frequency switching converters for electric drives that does not impose additional requirements on the hardware design phase and converter data acquisition. The method is based on optimizing the current controllers’ outp...
ABSTRACT The working principle of the matrix converter has been described by many authors in vari... more ABSTRACT The working principle of the matrix converter has been described by many authors in various ways. Especially, the introduction of the virtual DC link concept was one of the most important milestones in the matrix converter theory. However, the mathematical description is not symmetrical in this case. That is why a new approach presented in this article strives to symmetrize the matrix converter voltage and current transfer functions. For this purpose, new term is defined: DC-space vector.
The direct torque control (DTC) strategy is one of the most performance methods for induction mac... more The direct torque control (DTC) strategy is one of the most performance methods for induction machine (IM) drive torque control. The controlled stator magnetic flux and torque cannot be easily measured and therefore must be calculated using an IM mathematical model. This paper examines the impact of the replacement the original voltage IM model by Luenberger observer on the drive performance. As the original model requires only voltage and current, the observer is implemented in such a way that the same input variables can be used. The models are created and tests are carried out experimentally employing the dSPACE platform on induction motor of power 5.5 kW. The experimental results indicate better performance of the control strategy based on Luenberger observer.
Similarly as in field of combustion engines the efficiency map is very convenient tool for compar... more Similarly as in field of combustion engines the efficiency map is very convenient tool for comparison of different motor variants. The overall efficiency of the induction machine can be analyzed in this way too. It is well known, that behavior of the induction machine can be easily described by its state space model. However, this description is mostly used in order to analyze the dynamic behavior only. The efficiency of the machine remains mostly out of the scope of the published articles. Moreover, the rotor resistance can change significantly depending on the mode of operation of the induction motor and power loss caused by hysteresis and eddy currents is not included into the consideration at all. Therefore this paper strives first to derive analytically the efficiency of the induction machine and thus prepare the comparison basis for the future impact analysis of changing the machine parameters and respecting the power loss in magnetic yoke.
The paper deals with development of the induction motor drive direct torque control (DTC) based o... more The paper deals with development of the induction motor drive direct torque control (DTC) based on the next step voltage vector prediction. The principle of the method is explained and the system mathematical description is provided. The derived control algorithm is implemented both in the simulation software MatLab/Simulink and on the real induction motor drive with dSPACE control system. Simulated and measured results in steady states and transients are presented.
Sophisticated control of induction motor drive requires knowledge of the rotor angular velocity. ... more Sophisticated control of induction motor drive requires knowledge of the rotor angular velocity. In order to obtain the speed information an optical sensor is usually utilized. However, it is not always advantageous because of the whole drive robustness decrease caused by the speed sensor inclusion. The paper presents some simulation and measurement results in case of the MRAS (Model Reference Adaptive System) method employing in attempt to eliminate the induction motor drive speed sensor. The operation principle is explained and a mathematical model of the drive system is created. The MRAS method influence on the drive behaviour is examined in simulation environment and experimentally. Finally, the experimental results and comparison of the drive behaviour with and without the speed sensor are discussed.
ABSTRACT This paper examines the problem of adequacy in induction machine modeling and attempts t... more ABSTRACT This paper examines the problem of adequacy in induction machine modeling and attempts to provide a firmer basis for the selection of an appropriate model, to find a possible connection between the two most widespread models and to confirm or disprove their equivalence or differentness as the case may be.
Purpose. Creating a three-dimensional mathematical model of the electromagnetic field of an auger... more Purpose. Creating a three-dimensional mathematical model of the electromagnetic field of an auger electromechanical converter with the external solid rotor, taking into account the geometry peculiarities and the finite length factor. Methods. Calculation of the electromagnetic field distribution has been performed with the use of the computational solving the differential equations by the finite element method in a three-dimensional statement. Findings. It has been set that in the air gap the values of magnetic induction vary in the range of 0.7 -0.8 T, in the flanks of the stator teeth they reach the value of 2 T. Induction in a hollow ferromagnetic rotor varies mainly in the range of 1.3 -2.0 T, and in a thin layer with a thickness of 1.0 -1.5 mm, facing the stator surface, it reaches the value of 2.3 T. Within one pole pitch, the z-component maximum of the eddy currents density is 18ꞏ10 6 A/m 2 on the inner hollow rotor surface. It has been determined that, with the exception of the 'edge' rotor sections, where the transverse component of eddy currents prevails, as well as the sections of the magnetic flux "input" into the rotor, the eddy currents are mainly axial. A comparison of the results of measuring the electric field intensity on the rotor surface evidences a data difference of not more than 4%. The proposed model enables to optimize the design of the converter, in particular, to reduce the magnetic induction in the stator teeth. Originality. Numerical results have been obtained in the form of spatial patterns of distribution and graphical dependences that take into complete account the axial and tangential components of the electromagnetic field. The considered finite element model can be used when analysing the electromagnetic fields in electromechanical converters with a complex secondary part. This will give a possibility to consider the real threedimensional field character, caused by the design peculiarities and the final axial dimensions.
The authors propose new modiflcation of the direct torque control method based on voltage vector ... more The authors propose new modiflcation of the direct torque control method based on voltage vector prediction. The principle of the method is explained and the mathematical description of the system is provided. The control algorithm is implemented in simulation envi- ronment MatLab/Simulink and its behaviour is tested on the mathematical model of an induction motor drive. Then, the control algorithm is verifled on the real drive with induction motor with dSPACE control system. The results from the simulations and measurements are presented and compared with those when using the fundamental direct torque control method. 1. INTRODUCTION In 1986 Isao Takahashi and Toshihiko Noguchi presented a new control strategy of induction mo- tor control algorithm called direct torque control (DTC) (1). The method is based on transistor switching according to table uses hysteresis torque and magnetic ∞ux controllers. One of the dis- advantages is the relatively high torque ripple. A lot of modiflcations were performed since then. The most important are DTC with space vector modulation (2), multilevel inverter application (3) and predictive algorithms of DTC (4,5). The method described in the paper presents another modiflcation using prediction of voltage vector. It is based on the calculations of changes in stator and rotor magnetic ∞uxes and motor parameters. 2. PRINCIPLE OF VOLTAGE VECTOR PREDICTIVE DTC The basic theory of the proposed method flrstly predicts the stator magnetic ∞ux for the next cycle and then the voltage vector that should be switched on the inverter. The calculations are based on the every cycle motor state values (measured or estimated), motor parameters and reference values. Because the requirement of the method is the rotor ∞ux value knowledge, the estimator have to calculate with adequate precision and parameters of the induction machine must be known. The block diagram of the controlled system is depicted in Fig. 1 on the left hand side. The calculation of voltage for the next cycle is based on the induction motor stator voltage Equation (1). After discretisation it results in (2)
2014 International Conference on Applied Electronics, 2014
This paper describes a embedded controller for the matrix converter. Thanks to its computing thro... more This paper describes a embedded controller for the matrix converter. Thanks to its computing throughput it is suitable for university use, but it enables operation in the whole industrial rage thank to its construction. Besides the example usage in matrix converter, the control system is generally usable for various control tasks.
In this paper, the implementation of the Field Oriented Control and the Direct Torque Control in ... more In this paper, the implementation of the Field Oriented Control and the Direct Torque Control in matrix converter supplied induction motor drives is analysed, and compared with the implementation in drives supplied by the Voltage Source Inverter. The analysis is accompanied by the results of numerical simulations and experimental implementations of these two control methods.
The presented paper deals with matrix converters pulse width modulation strategies design with em... more The presented paper deals with matrix converters pulse width modulation strategies design with emphasis on the electromagnetic compatibility. The most of the contemporary modulation strategies are able to provide practically sinusoidal waveforms of the input and output currents with negligible low order harmonics, and to control the input displacement factor. A special digital control system was developed for the realized experimental test bed which makes it possible to achieve greater throughput of the digital control system and its variability.
The authors propose to work out common principles of synthesis of electromagnetic fleld models fo... more The authors propose to work out common principles of synthesis of electromagnetic fleld models for the main types of electrical machines. The main objective is to create fleld models of electric machines by inheritance of their characters from the original Maxwell's equations. An inverse problem is being also solved | the synthesis of electric machine electromagnetic fleld equations using object-oriented design. Object-oriented design (OOD) implements the idea of solving problems using models based on the concepts of the real world. Fundamental element is an object that combines the data structure (parameters) to the behaviour (calculating procedures). Philosophy of knowledge representation in the form of objects of prisoners in their data and procedures developed by G. Booch, but so far only been applied in the fleld of software development, as well as an ideological foundation of programming languages such as Java, C++, C#, Visual Basic, Delphi (1). Consideration of OOD princi...
2020 21st International Scientific Conference on Electric Power Engineering (EPE)
This work deals with a real-time optimum flux search control (SC). The method is integrated into ... more This work deals with a real-time optimum flux search control (SC). The method is integrated into Predictive Torque Control (PTC) of induction motor drive (IMD). The proposed predictive search control searches the optimum stator flux amplitude, at which the current amplitude is the lowest. The output of the SC is used as a reference for the PTC controller. As the control variable of the proposed SC, the predicted stator current vector amplitude is utilized. The method was verified experimentally on a laboratory drive with a 5.5 kW induction motor. The IMD achieves a current minimization while maintains the working point defined by the speed and load. The experiment shows good results during steady-state and sufficient performance during transients.
2019 International Conference on Electrical Drives & Power Electronics (EDPE)
Three methods of cooling gallium nitride (GaN) transistors have been tested and directly compared... more Three methods of cooling gallium nitride (GaN) transistors have been tested and directly compared together. Under similar conditions, top side cooled GaN was compared to the bottom side cooled type; both were of the same electrical parameters and were mounted on FR4 (fibreglass resin) and IMS (insulated metal substrate) printed circuit boards. At equal dissipated power the proposed bottom side cooled transistor on IMS board reaches half the temperature compared to the top side cooled one and one fourth of the temperature compared to the bottom side cooled GaN on FR4 board. A High speed driver is placed close to the transistor also on the IMS board to reduce parasitic inductance of the gate driving path from control board to the high power side on the IMS board.
2017 18th International Scientific Conference on Electric Power Engineering (EPE)
Direct torque control (DTC) is one of the best performing strategies for induction motor control ... more Direct torque control (DTC) is one of the best performing strategies for induction motor control in many applications. However, this method suffers from a few disadvantages. Very important one is the presence of ripples in the torque waveform. The main reason of their presence is the inaccurate model of the motor. This paper utilizes Luenberger observer to calculate the model of the motor instead of the classical one. The DTC strategies with its original model and with Luenberger observer are created on dSPACE ds1103 platform. The results from experiment on a specific induction motor drive are shown. The paper shows better performance of the DTC with model based on Luenberger observer. The ripples in torque waveforms were lowered while switching frequency of the transistors remained the same.
Modernization consists of a new compact drive unit for the Citröen Berlingo Electrique electric v... more Modernization consists of a new compact drive unit for the Citröen Berlingo Electrique electric vehicle. The drive unit integrates a power converter for the traction motor, a DC/DC low voltage converter, an on board charger and an electronic control unit (ECU). The new aircooled power converter is lightweight and more efficient due to a modern equipment used. The new ECU uses controller area network (CAN) to communicate with the power converters and also collects all the measured data that can be transferred in real-time during drive. This vehicle also currently provides a test and measurement platform for Master's Degree students.
Matrix converter belongs to direct frequency conver ter category. Output voltage is made by direc... more Matrix converter belongs to direct frequency conver ter category. Output voltage is made by direct swit ching of input phases to output phases. This fact means t hat converter does not need DC-link capacitor which in reases the costs and volume requirements of the converter. The absence of DC-link capacitor is one of the mai n advantages of the matrix converter. On the other ha nd it means that the output voltage amplitude is li mited by 86.6% of the input voltage amplitude. Higher vol tages can be achieved with overmodulation, which ca uses input current distortion. The other advantages of t he converter compared to conventional indirect freq uency converter are: power factor regulation, operation i n all four quadrants, its high dynamic, sinusoidal current consumption, nearly sinusoidal output voltage wavef orm with low harmonic content, and high efficiency. To the main disadvantages belongs: amount of semiconductor devices, limited output voltage amplitude, and complicated contro...
Inductive power transfer (IPT) applications, such as stationary charging of electric vehicles (EV... more Inductive power transfer (IPT) applications, such as stationary charging of electric vehicles (EVs), at least moderate coupling between the coils to achieve high efficiency, but the coefficient k typically varies between of 0.1 to 0.4, depending on the displacement of the coils according to SAE J2954. Thus, accurate and reliable methods for estimation of k are required for positioning of the EV to achieve optimal alignment with the charging pad. Additionally, in IPT, numerous control strategies are available for regulating output power and optimizing system efficiency that require an accurate estimate of the mutual inductance or k. However, existing estimation methods tend to require detailed a-priori information of a large number of circuit parameters, or they need measurement of currents or voltages in both primary and secondary sides. This paper presents a preliminary evaluation of a novel, primary-side method to estimate k, which is based solely on the frequency response of the ...
Gallium nitride (GaN) devices are becoming more popular in power semiconductor converters. Due to... more Gallium nitride (GaN) devices are becoming more popular in power semiconductor converters. Due to the absence of the freewheeling substrate diode, the reverse conduction region is used in GaN transistors to conduct the freewheeling current. However, the voltage drop across the device in the reverse conduction mode is relatively high, causing additional power losses. These losses can be optimized by adequately adjusting the dead-time issued by the microcontroller. The dead-time loss minimization strategies presented in the literature have the common disadvantage that either additional hardware or specific converter data are needed for their proper operation. Therefore, this paper’s motivation is to present a novel dead-time loss minimization method for GaN-based high-frequency switching converters for electric drives that does not impose additional requirements on the hardware design phase and converter data acquisition. The method is based on optimizing the current controllers’ outp...
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