Frequency Converter Circuit Research Articles

Research of control systems for lifting and transport mechanisms

THE PURPOSE. To investigate the existing methods of frequency control and their influence on the characteristics of the asynchronous motor, including the energy parameters. Consider new circuit solutions of the control type under study. Create a mathematical model of each of the methods of frequency control. To analyze the results obtained from the point of view of the behavior of mechanical, electromechanical and energy components. METHODS. When solving this problem, the method of computer simulation modeling, implemented by means of Matlab Simulink, was used. RESULTS. In this paper, various aspects of electric drive systems based on asynchronous motors with the use of cascade switching are studied and described, existing connection schemes for such systems are analyzed, and several new options with improved characteristics are proposed. A comparative analysis of various connection schemes is made, the most interesting results of such analysis are presented, and conclusions are drawn about the future prospects of certain circuit solutions.Electric drive systems were modeled in the Simulink MATLAB environment using software tools to demonstrate the operation parameters of the considered circuits. CONCLUSION. Various schemes for switching on the asynchronous motor in the Simulink Matlab environment were investigated. The results of the study revealed the potential usefulness of using a circuit with a transformer in the rotor circuit, as well as the construction of a multi-motor electric drive with a common transformer and a common frequency converter circuit. The efficiency of parallel connection of rotary circuits of a two-motor electric drive was demonstrated. The methods of returning the sliding energy to the network are also compared, and their effectiveness in a comparative analysis with the operation in the closed-loop rotor mode is demonstrated.

Research of frequency control systems for lifting and transport mechanisms

THE PURPOSE. To investigate the existing methods of frequency control and their influence on the characteristics of the asynchronous motor, including the energy parameters. Consider new circuit solutions of the control type under study. Create a mathematical model of each of the methods of frequency control. To analyze the results obtained from the point of view of the behavior of mechanical, electromechanical and energy components. METHODS. When solving this problem, the method of computer simulation modeling, implemented by means of Matlab Simulink, was used. RESULTS. In this paper, various aspects of electric drive systems based on asynchronous motors with the use of cascade switching are studied and described, existing connection schemes for such systems are analyzed, and several new options with improved characteristics are proposed. A comparative analysis of various connection schemes is made, the most interesting results of such analysis are presented, and conclusions are drawn about the future prospects of certain circuit solutions.Electric drive systems were modeled in the Simulink MATLAB environment using software tools to demonstrate the operation parameters of the considered circuits. CONCLUSION. Various schemes for switching on the asynchronous motor in the Simulink Matlab environment were investigated. The results of the study revealed the potential usefulness of using a circuit with a transformer in the rotor circuit, as well as the construction of a multi-motor electric drive with a common transformer and a common frequency converter circuit. The efficiency of parallel connection of rotary circuits of a two-motor electric drive was demonstrated. The methods of returning the sliding energy to the network are also compared, and their effectiveness in a comparative analysis with the operation in the closed-loop rotor mode is demonstrated.

Efficient Control of Induction Motor Current in a Frequency-Controlled Electric Drive

An analysis of methods for controlling the current of an asynchronous electric motor in a frequency-controlled electric drive is performed. The disadvantages of a control system with relay current controllers that provide system operation in the “current corridor” mode are shown. Such disadvantages as increased thermal losses in the transistors of the frequency converter are caused by the unstable switching frequency of the motor current. The relevance of the principles of current control using the predictive model to form control actions in the frequency converter circuit with relay controllers is noted. A method of current control in an asynchronous electric drive is considered that makes it possible to stabilize the switching period of the inverter power switches when controlling the current in the motor. To obtain this result, it is proposed to influence the width of the hysteresis loop of the relay current controllers and form it depending on the parameters of the load circuit. The required accuracy of the current control is maintained. The structure of the control system is proposed, in which the considered method is implemented. A key element of the system is a computing unit that generates signals that set the required width of the hysteresis loop of the relay controllers. The method of predicting changes in the controlled current after the next switching of transistors in the inverter of the frequency converter of the electric drive is the analytical basis of the calculations. Analytical expressions providing the calculations necessary for the computing unit operation are presented. The effect of applying the relay current controllers with variable hysteresis in the control system of a frequency-controlled electric drive is shown.

IMITATION MODEL OF A HIGH-SPEED INDUCTION MOTOR WITH FREQUENCY CONTROL

Purpose. To develop the imitation model of the frequency converter controlled high-speed induction motor with a squirrel-cage rotor in order to determine reasons causes electric motor vibrations and noises in starting modes. Methodology. We have applied the mathematical simulation of electromagnetic field in transient mode and imported obtained field model as an independent object in frequency converter circuit. We have correlated the simulated result with the experimental data obtained by means of the PID regulator factors. Results. We have made the simulation model of the high-speed induction motor with a squirrel-cage rotor speed control in AnsysRMxprt, Ansys Maxwell and Ansys Simplorer, approximated to their physical prototype. We have made models modifications allows to provide high-performance computing (HPC) in dedicated server and computer cluster to reduce the simulation time. We have obtained motor characteristics in starting and rated modes. This allows to make recommendations on determination of high-speed electric motor optimal deign, having minimum indexes of vibrations and noises. Originality. For the first time, we have carried out the integrated research of induction motor using simultaneously simulation models both in Ansys Maxwell (2D field model) and in Ansys Simplorer (transient circuit model) with the control low realization for the motor soft start. For the first time the correlation between stator and rotor slots, allows to obtain minimal vibrations and noises, was defined. Practical value. We have tested manufactured high-speed motor based on the performed calculation. The experimental studies have confirmed the adequacy of the model, which allows designing such motors for new high-speed construction, and upgrade the existing ones.

Analysis Method for Finding the Sources of Failures in Circuits with a Frequency Converter

The dynamic development of devices that use electrical and electronic components makes it necessary to eliminate sources of interference occurring in circuits with systems of this type. These disturbances adversely affect the correct functioning other systems that work together as a network, as well as equipment located in neighbouring systems. The article presents a method of the analysis of the sources of faults occurring in electrical circuits, using a frequency converter. The discussed principle of the operation of the frequency converter and the impact of disturbances generated by these installations are presented in this article. The evaluation methodology of the installation is presented using the requirements of the Harmonized Standards and the authors’ own solutions. The verification of the method was conducted by applying it to a real electrical circuit. The potential sources of electrical faults were identified that were caused by the frequency converters and its circuit. The developed and presented analysis method of the faults sources can be used for evaluating other circuits of this type in which one of subsystems is a frequency converter circuit.

A Low Power Temperature to Frequency Converter for the On-Chip Temperature Measurement

In this paper, we are proposing a simple energy efficient on-chip temperature to frequency converter circuit. The proposed arrangement senses the temperature in terms of the proportional to absolute temperature (PTAT) current. The temperature equivalent PTAT current is then converted into frequency using the source coupled multivibrator circuit. The proposed circuit has been designed and fabricated in a standard 180-nm CMOS technology and occupies silicon area of $\approx 0.058$ mm $^{2}$ . The measurements were performed on ten prototypes. The proposed architecture is capable of working in the temperature range of −40 °C to +85 °C with the supply voltage of 0.9 V ± 10%. The smart temperature sensor achieves a maximum temperature inaccuracy $\approx 600$ nW at +85 °C for 0.9 V supply voltage.

Construction Analysis of High Frequency Converter Circuit on Switching Power Supply

Construction Analysis of High Frequency Converter Circuit on Switching Power Supply

A digital SQUID controller

We describe the performance of an improved DC SQUID controller base upon a PC data acquisition board with a single digital signal processor (DSP). The main DSP algorithm, which handles the flux-locked-loop, is optimally written in assembly language. To improve the performance of the controller, we have added a custom built frequency converter circuit that matches the modulation frequency of the DSP system to that of a commercial SQUID sensor and preamplifier. The noise level of the DC SQUID controller system is comparable with a commercial analog system, ∼4μΦ 0/ Hz at 100 Hz . The current system could control up to 5 SQUID channels.

AC to AC Frequency Converters for Induction Heating

A flow chart for simulation of ac to ac frequency converter is developed. Generalised equations for the digital analysis of the converter circuit are derived and the circuit operation is digitally computed. The experimental results of a prototype frequency converter circuit are presented.