Armature Voltage Research Articles

ПЕРЕТВОРЮВАЧ АСИНХРОННОГО ЕЛЕКТРОПРИВОДА ТА ЕЛЕКТРОПРИВОДА ПОСТІЙНОГО СТРУМУ

A converter is considered that canprovide control of both anasynchronous electric drive and a DC electric drive. In an asynchronous electric drive control of a three-phase frequency converter by reactive power; in a DC electric drive the armature voltage is formed by PWM modulation of two arms of the frequency converter, and the voltage of the field winding is PWM modulated by the third arm of the converter. Ensures high-quality control of electric drives. Ref. 10, fig. 3.

Microsatellite Yaw-axis Attitude Control System Using Model Reference Adaptive Control Based PID Controller

This paper presents a Model Reference Adaptive Control (MRAC) based Proportional Integral and Derivative (PID) controller for microsatellite yaw-axis Attitude Control System (ACS). The objective is to combine the algorithm of MRAC with PID to improve the performance of a microsatellite system especially settling time. MRAC based PID controller for yaw-axis ACS was modelled and simulated in MATLAB/Simulink to meet transient response characteristics specifications. The performance of the system was evaluated in terms of rise time, settling time, maximum overshoot, and steady-state error including energy consumption measured based on armature voltage of the direct current motor. The simulation results revealed that the proposed system meets all the performance specifications and outperformed classical PID controller for adaption gain of 0.2 to 20. When compared with PID and Proportional Derivative (PD) based Controllers in previous study for adaption gain of 10, 15, and 20, the proposed system proved to be superior. Generally, the choice of the MRAC based PID controller considering the range of adaption gain (γ = 0.1 to 20) should be based on either transient response advantage or energy consumption or even both over PID controller. The significance of this study is that an MRAC based PID controller that offered wide range of adaption capability for microsatellite ACS has been proposed.

A novel jittered‐carrier phase‐shifted sine pulse width modulation for cascaded H‐bridge converter

AbstractCarrier phase‐shifted sine pulse width modulation is a common modulation strategy for medium‐ and low‐voltage cascaded H‐bridges (CHB). This paper proposes a novel jittered‐carrier phase‐shifted sine pulse width modulation (JCPS‐SPWM) to reduce the total harmonic distortion (THD) of the converter. It makes the carrier jitter regularly while the total switching times remain unchanged, which reduces the THD of the bridge arm voltage and current by moving the low‐order output harmonics of the bridge arm voltage and current to filterable high‐order harmonics. Since the total number of switching times remains unchanged, this modulation strategy will not cause any increase in switching loss. A seven‐level CHB simulation model and an experimental prototype are built to verify the effectiveness of the approach. The results show that harmonic content can be reduced by 47.5% compared with the traditional method, thus verifying the effectiveness of the JCPS‐SPWM.

Speed Regulation of Direct Current Motor Using AC-DC Buck Boost Converter by using Soft Starter Method

Regulating the speed of direct current motors is essential in a variety of industries. The speed of direct current can be controlled by adjusting armature resistance, voltage and field current. Voltage regulation can be achieved by utilizing an AC-DC buck-boost converter for increasing and decreasing voltage. Additionally, it is important to take into account the initiation of a DC motor. Initiating operation of a DC motor necessitates a significant current to prevent potential harm to the insulation. Due to this, it is important to keep the current low when starting a DC motor. One method to decrease the initial current is by using a soft starter, where the reference current is compared to the motor's armature current. This research resulted in the development of a circuit that efficiently adjusts voltage levels with a pulse generator, making it easy to regulate the speed of direct current motors. A PI controller can also regulate the velocity of a direct current motor. During the trial, it was discovered that the initial current in a direct current motor never went beyond 25.6 amperes, making this technique highly efficient for initiating a direct current motor.

Simulation on Operating Characteristics of Shunt DC Motor

By comparing the literature at home and abroad, according to the working process and principle of shunt excited DC motor, the working characteristics and mechanical characteristics of the motor are analyzed by Simulink software. Among them, the working characteristics cover the speed characteristics and torque characteristics, and the mechanical characteristics include the inherent mechanical characteristics and artificial mechanical characteristics. The working characteristics of motor speed and torque are analyzed when the magnetic flux and armature resistance are changed. At the same time, the effects of changing the armature voltage, armature resistance and series resistance on the inherent and artificial characteristics of the motor, and the suggestions for starting the motor are given.

Optimized PID and NN-based Speed Control of a Load-coupled DC Motor

In this work, three control strategies are presented, compared, and discussed, applied on a load-coupled DC motor. The purpose is to control in an optimal way the motor speed in terms of the armature voltage. Two strategies are based on PID control, working on the classical PID controller and the optimized one by using particle swarm optimization (PSO) to tune the PID controller parameters. The other strategy is based on neural networks (NNs) where two NNs are built to model and control the system. Based on the results, all the strategies reach excellent performances, however, in terms of system response characteristics like rising time or settling time the PID-based controllers show faster responses than the NN controller. Moreover, by comparing these results with other studies that are working with an unloaded DC motor and even when the working system is more complex, the obtained results have a better performance.

An Active DC Fault Current Limiting Control for Half-Bridge Modular Multilevel Converter Based on Arm Voltage Reconstruction

An Active DC Fault Current Limiting Control for Half-Bridge Modular Multilevel Converter Based on Arm Voltage Reconstruction

Method to Enable Reduced Sensor Capacitor Voltage Estimation in Modular Multilevel Converters

Bulk power applications such as shipping increasingly consider multilevel converter topologies such as modular multilevel converters (MMC), which offers the advantages of scalability, good power quality, and reconfigurability. The internal functioning of MMC requires complete knowledge of the capacitor voltages that make up their submodules meaning a large number of sensors are needed and thus a high number of potential points of failure exist. To increase reliability and reduce investment costs, state estimation techniques such as KALMAN filters have been employed to replace the physical sensors. Analytical techniques based on the knowledge of arm current, arm voltage, and submodule states have also been developed. These techniques exploit the fact that at an insertion index of 1, the arm voltage equals the capacitor voltage on the submodule which permits the estimation algorithm to refresh periodically with measured data thereby increasing the accuracy. This method requires a long refresher time, especially when many submodules are used per arm. In this study, we propose an improved analytical estimation by not only using unity insertion indices, but also exploiting transitions between two successive insertion indices. The study was carried out on a 4 submodule per arm MMC system. The estimated capacitor voltages were then compared with sensor-based voltage measurements confirming the validity of the proposed method. It was then integrated into a complete MMC controller including the inner controls such as circulating current and capacitor voltage balancing.

Different Chopper Types for Supply Separately Excited DC Motor

Abstract Nowadays saving the planet’s resources plays a very important role in improving our life conditions. The purpose of the paper is to supply the separately excited dc motor by using different chopper circuits. A very sustainable solution is to replace the resistors from classic theory with dc choppers for better efficiency. The armature voltage can be controlled by using IGBT chopper and the PWM signal received from controller is done with a dedicated block created by MATLAB environment. The advantages of developing this technique are that the speed changes proportionally with armature voltage and inversely with field voltage by keeping field and armature voltage constant respectively. The chopper designed with IGBT and Diode modules offers good control at any frequency value and the speed, the armature current and electromagnetic torque of DC motor can be control. In this paper, different choppers had been simulating were working in four quadrants for supply an excited dc motor by using Matlab program.

An MMC control strategy without bridge arm current sensors

Each bridge arm of a modular multilevel converter (MMC) is connected in series with multiple submodules. This structure increases the amount of current detection, making it necessary to have a number of current sensors in operation, which increases the system cost. For this reason, this paper proposes an MMC control strategy that does not require bridge arm current sensors. Firstly, the nearest level modulation (NLM) strategy requires the bridge arm current to be used to determine the submodule entry direction. In this case, this article proposes a method for determining the input direction of the submodule based on the capacitive voltage of the submodule, which calculates the input method of the submodule by analyzing the state quantities in the bridge arm voltage switching function, omitting the bridge arm current sensor and reducing the cost. Secondly, the traditional MMC circulation suppression method needs to detect the bridge arm current to calculate the circulation. However, this paper proposes an indirect circulation suppression method by suppressing the unbalanced voltage based on the analysis of the circulation generation mechanism. Finally, simulations and experiments validate the effectiveness of this method and lay the foundation for the next engineering application.

Design and Analysis of Battery Management System for Electrical Vehicles

Abstract: The quantity of pollution that is emitted into the atmosphere will only continue to climb as the number of people who drive automobiles powered by internal combustion engines continues to rise. To reduce emissions of greenhouse gases, academics and companies on every continent are now focusing their attention on the research and development of more sophisticated technologies for electric cars. During this investigation, we are going to model and create a two-way power converter for electric automobiles. Batteries, a dc-dc converter, and a dc motor are just a few of the many diverse parts that make up the power electronics module. It is advised that the starting battery be charged to about 90% of its capacity before using the motor mode, which has a discharge current of 44.5 A. The battery stack has a maximum capacity of 100 ampere-hours, and its nominal voltage is 350 volts. This is the greatest amount of energy that it can store. Direct current (DC) machines have the potential to generate up to 250 horsepower, provided that the armature voltage is 500 volts and the field voltage is 300 volts, respectively. The mode of operation for the power converter is determined by the readings of torque that are obtained by the DC machine when it is operating in the motor mode and the generator mode, respectively. The processes of charging and discharging batteries have been monitored and handled in relation to the wide variety of modes of operation that may be found in DC machines. This was done in order to make full use of the capabilities of these machines. The bidirectional dc-dc converter, which may operate in either direction, is managed by a fuzzy logic controller. This allows the converter to work in either direction. It's likely that the converter and controller that's been shown here are all that's needed for charge management and running the motor in electric automobiles.

Equivalent model of nearest level modulation for fast electromagnetic transient simulation based on DC voltage control loops of sub‐modules in modular multilevel converter

AbstractThe nearest level modulation (NLM) is used to automatically generate ac side voltages of sub‐modules in modular multilevel converter (MMC). Existing literature seldom presents models that describe complex NLM processes. This paper proposes an equivalent model of the NLM to simply describe and simulate the complex NLM process. The main contribution of this study is to build the model of NLM with fast simulation speed for the application focuses on the simulation accuracy at the millisecond level. The duty cycle of the average model generated by the NLM in sub‐modules of the MMC is divided into two components, which are the stable component for generating the bridge arm voltage and the fluctuation component for balancing the dc side voltage of sub‐modules, respectively. The stable component is generated by the modulation wave of the MMC control system. By adding a voltage control closed loop to the sub‐module, the fluctuation component for balancing the dc side voltages of sub‐modules can automatically adjust the ac side voltages of sub‐modules. The proposed equivalent model of NLM improves the simulation speed and has the same effect with the traditional NLM within the low‐frequency range or with the time step of millisecond level.

Submodule Capacitor Voltage Ripple Reduction of Full-Bridge Submodule-Based MMC (FBSM-MMC) with Non-Sinusoidal Voltage Injection

The full-bridge submodule (FBSM)-based modular multilevel converter (FBSM-MMC) offers promising performance due to its ability to output negative FBSM voltage. This paper studies this ability of the FBSM-MMC under zero-sequence voltage injection (ZSVI) and second-order harmonic current injection (SHCI). The focus of the research is to redistribute the FBSM powers by injecting an additional power degree of freedom, resulting in a smaller FBSM capacitor voltage ripple, while keeping the maximum AC output voltage for a given fundamental frequency component of the arm voltage reference. Accordingly, a control strategy was developed, based on non-sinusoidal ZSVI, and SHCI is proposed for further improving the performance of the FBSM-MMC. The proposed non-sinusoidal ZSVI contains a higher sinusoidal third-order harmonic component than that of pure sinusoidal third-order voltage injection (THVI) when operating under the same maximum AC output voltage. By implementing this solution, a smaller amplitude of the injected second-order harmonic current can be achieved, producing a lower power loss in the FBSM-MMC. Considering the proposed solution, the relationship of the arm powers and FBSM capacitor voltages are also discussed. Finally, the simulation results and experimental results are presented to verify the effectiveness of the theoretical analysis of the proposed method.

DC motor control using model reference adaptive control

Despite having higher maintenance costs than AC motors, DC motors had been widely employed in the industry due to their outstanding speed control capabilities. This employment increased due to the DC output of some renewable sources recently. This article introduces the speed control of DC motors using model reference adaptive control (MRAC). This control is achieved through regulating the armature voltage at different load changes. A comparison between the proposed adaptive controller and optimized PI controller using the elephant herding optimization (EHO) is presented. The PI controller parameters were optimality adjusted to minimize the integral absolute error, minimum overshoot, and minimum settling time. Computer simulations show that the suggested MRAC is preferable to a traditional optimized PI controller. In addition, the proposed controller is effective in regulating the DC motor over a broad range of operating speeds.

DC motor control using model reference adaptive control

Despite having higher maintenance costs than AC motors, DC motors had been widely employed in the industry due to their outstanding speed control capabilities. This employment increased due to the DC output of some renewable sources recently. This article introduces the speed control of DC motors using model reference adaptive control (MRAC). This control is achieved through regulating the armature voltage at different load changes. A comparison between the proposed adaptive controller and optimized PI controller using the elephant herding optimization (EHO) is presented. The PI controller parameters were optimality adjusted to minimize the integral absolute error, minimum overshoot, and minimum settling time. Computer simulations show that the suggested MRAC is preferable to a traditional optimized PI controller. In addition, the proposed controller is effective in regulating the DC motor over a broad range of operating speeds.

A variable frequency injection method for modular multilevel converters in variable speed drives

Modular multilevel converter (MMC) is a novel circuit that has appeared in the last few decades, and has been extensively applied to medium/high voltage scenarios, especially in motor drive owing to its scalability and easy to supply a higher number of output voltage levels. As theoretical analysis shows, the sub-module (SM) capacitor voltage magnitude is positively related to the converter output current amplitude and conversely connected to the fundamental frequency. Therefore, the prime challenge of applying MMC to variable speed drives is that there is a huge voltage oscillation in SM capacitor voltage during low-speed working. An innovative high-frequency voltage injection modality to diminish the fluctuation of the capacitor voltage in variable speed drives is proposed in this paper, in which the frequency of the injected component can be changed with the operating frequency of the converter and the low frequency component of power can be converted into high frequency component. The discussed measure not only significantly reduces the voltage float in capacitor, but also avoids the overmodulation of arm voltage modulation waveform caused by high frequency of injection component when converter works in low frequency. With the improved method, the performance of motor at low frequency is enhanced. Finally, the feasibility and effectiveness of the proposed improved high-frequency voltage injection method are verified by simulation and experiment.

A Sliding-Mode Observer for MMC-HVDC Systems: Fault-Tolerant Scheme With Reduced Number of Sensors

The modular multilevel converter (MMC) has been widely adopted in different applications, such as high-voltage direct current (HVDC), electric drives and static synchronous compensators. Despite the application, MMC realization requires a high number of power electronic components, sensors, and communication cables. This paper proposes a sliding-mode observer for capacitor voltages of the MMC, using the measurements of arm currents and arm voltages. A linear corrector within the hysteresis band is proposed to reduce the chattering in the observer dynamics. Moreover, guidelines for tuning the observer gain are presented. The SM capacitance value is included as a parameter uncertainty of the observer. The proposal reduces the requirements of voltage sensors and optical links in MMC and allows fault-tolerant operation. The proposed observer performance is evaluated through a simulation of 100 MVA three-phase MMC-HVDC during initialization, steady-state, and submodule failures. The effect of the switching and sampling frequencies on the observer performance is also evaluated. Finally, experimental results validate the proposal in a downscale 3 kVA single-phase MMC prototype.

PEMODELAN DAN PENGENDALIAN MOTOR DC TYPE DRIPPROOF-SEPARATELY VENTYLATED DENGAN TEGANGAN JANGKAR

A dc motor is a machine that converts dc electrical energy into mechanical energy. One way to assess the work of a dc motor is to know the amount of current and speed in the initial conditions before adjustments/changes are made. Current and speed settings can be made by adjusting the motor armature voltage at starting. The greater the time the armature voltage reaches its nominal value, the armature current will be smaller so that it is safe for the motorbike and vice versa.

Data Driven Model Predictive Control for Modular Multilevel Converters With Reduced Computational Complexity

Model predictive control (MPC) has become increasingly popular among researchers for modular multilevel converters (MMCs) due to its ability to incorporate multiobjective control and provide superior dynamic response. However, it is computationally challenging to implement it on MMCs when the number of submodules is increased. This paper proposes a finite control set (FCS) model predictive control (MPC) with reduced computational complexity for modular multilevel converters (MMCs). To accomplish this goal, a reduced order data-driven model is obtained using sparse identification of nonlinear systems (SINDy) by incorporating the input terms in the load current and circulating current dynamics. As a result, the need to use the arm voltages or the submodule capacitor voltages dynamic equations as in the case of a conventional FCS-MPC is eliminated. To improve the output current total harmonic distortion (THD) and reduce the effect of higher switching frequencies caused by the FCS-MPC, an updated cost function is proposed. The effectiveness of the proposed technique is validated by simulation and experimental results.

A Three-stage AC side startup strategy for hybrid MMC

When a hybrid modular multilevel converter (MMC) starts from the AC side, the capacitor voltages of full-bridge submodules (FBSMs) will be twice those of half-bridge submodules (HBSMs) in the uncontrolled charging stage due to their structural differences, making it difficult to further charge the SMs in the ensuing controlled charging stage. To solve this problem, a three-stage AC-side startup strategy for hybrid MMCs is proposed. Compared with conventional closed-loop startup strategies, it charges HBSMs and FBSMs simultaneously with the third harmonic injection method, which eliminates the inrush current. And then the HBSMs are charged separately by orthogonal decomposition of the arm voltage after FBSMs are fully charged, which avoids overcharging the FBSMs. Thus, hybrid MMCs can start from the AC side quickly without inrush current, and the unbalance between different SMs is eliminated. The necessity and feasibility of the proposed strategy are discussed in detail. Aiming at possible errors in arm voltage orthogonal decomposition and current phase tracking, control loops for HBSMs and FBSMs are derived and analyzed. Finally, the complete three-stage startup strategy is designed. Simulation results and experimental results are provided to support the theoretical analysis and validate the proposed strategy.