Switch Tube Research Articles

HIGH-VOLTAGE PULSE GENERATOR ON THE BASE OF PLASMA TUBE WITH COLD CATHODE IN CROSSED FIELDS

A new scheme of the high-voltage pulse generator with a partial discharge of a capacitive energy storage on the base of the magnetically-controlled opening plasma switch tube is presented and investigated. The high-current magnetron discharge with the secondary-emission cold cathode in crossed-fields is used in the tube. The particularity of the generator scheme is the application of the anode voltage to the tube through a voltage divider to decrease the magnetic control power. The other special feature is the usage of an additional closing switch device (e.g., an ignitron) which is connected in series with the tube. The latter device is being triggered with some delay relatively the activation of the plasma switch tube. This technical approach creates conditions for a generation of the load current pulses with a minimal jitter due to ignition of a primary (pre-ionization) discharge in the tube before triggering the closing device. Therefore, the start of the load current pulses is determined by triggering the closing device however the finish of the same thing is depended on the magnetron discharge switching-off through magnetic field turning-off in the tube. The new generator provided a stable generation of pulses at the amplitude of up to 200 A, duration in the range of 15…70 μs, the anode voltage of up to 20 kV and the average power of up to 100 kW. The pulse generator is designed for use in radio electronic and electro physical systems as well as in a plasma technology.

An ultra-high gain boost converter with low switching stress for integrated multi-energy storage systems

In this paper, a high-gain low-switching-stress coupled-inductor with high voltage step-up voltage multiplier cells quadratic boost converter (VMC-QBC) is proposed. The turn ratio of the coupled inductors and the switch duty cycle increase the dynamic gain, and the two degrees of freedom adjustment and modularity of the voltage multiplier cells (VMC) make the structure more flexible. The use of the same drive signal for both switches makes control easier. While achieving multi-stage boosting and multiplication boosting from low to medium duty cycle, the passive clamping circuit absorbs the energy leaked by the coupled inductor, thus reducing the stress on the switching tube and alleviating the diode reverse recovery problem. A non-ideal model with parasitic parameters is developed to analyse the real voltage gain and the converter losses to give design guidelines. A 300 W prototype is designed and tested. The state space model of the converter is established and the working principle is analysed. Compared to other high-gain quadratic boost converters, the proposed converter has continuous input current, common ground characteristics, and high voltage gain at low to medium duty cycles to accommodate integrated multi-energy storage systems.

Dead-Time Free Modulation Scheme for IM Drive System Fed by Voltage Source Inverter

During the modulation process of the VSI motor drive system, the nonlinear errors caused by the dead-time and conduction voltage drop will increase the phase current harmonic distortion and the torque ripple. To solve this problem, a novel dead-time free modulation scheme is proposed in this paper. In the non-zero crossing region of the phase current, the switching tube, whose body diode can provide a continuation path, is set as off-state, the driving signal is only implemented on another switching tube with the same bridge arm, and the errors caused by the conduction voltage drop and switching delay are compensated to the pulse duration. At the same time, to suppress the zero current clamp effect that exists near the zero crossing point of the phase current, another modulation scheme for the phase current crossing zero in advance is proposed, which avoids the complicated determination and calculation of the current polarity near the zero crossing point of the current. Both of the above modulation schemes eliminate the dead-time, and the switching principle is presented. In addition, to suppress the impact of the current ripple and high-frequency noise on the accuracy of the phase current detection, a second-order resonance digital filter without phase shift is introduced. Finally, compared to two deadtime compensation methods, the effectiveness and superiority of the proposed dead-time free modulation scheme are verified by the experimental results.

Research on the Control and Modulation Scheme for a Novel Five-Switch Current Source Inverter

Different from the voltage source inverter (VSI), the current source inverter (CSI) can boost the voltage and eliminate the additional passive filter and dead time. However, the DC-side inductor current is not a real current source and is generated by a DC voltage supply and an inductor. Under different switching states, the DC-side inductor will be charged or discharged, which leads to the DC-side inductor current being discontinuous or increasing. To solve the control problem of the DC-side inductor current of the CSI, a novel single-phase CSI topology with five switching tubes for grid-connected applications is proposed. Firstly, the reference calculation method and the hysteresis loop control scheme for the DC-side inductor current are proposed, and the adjustable and constant DC-side inductor current are obtained. Since the PWM signals cannot be directly implemented to the switching tubes, the modulation strategy for the single-phase CSI is proposed in this paper. Then, an active damping method based on the feedback capacitor voltage is presented to suppress the resonance peak caused by the LC filter on the grid side. Finally, the math model of the AC-side structure is established, and the optimal proportional-resonant controller parameters’ design method is explored by the amplitude–frequency characteristic curves. The simulation and experiment are implemented for the proposed CSI topology. The results show that a high-quality power with a good control performance can be obtained with the proposed CSI topology.

Output voltage control of DAB converters based on uncertainty and disturbance estimation.

The dual active bridge (DAB) converter is a power electronic device commonly used for DC voltage regulation and stabilization. However, during its control process, external disturbances, load variations, input voltage variations, switching tube voltage drops, dead time, etc. lead to errors in the control output, thus reducing the control accuracy of the system. Therefore, this article propose a robust control scheme for the output voltage based on uncertainty and disturbance estimator. In this article, an average small-signal model of the dual active bridge converter was established in terms of the basic principles and operation mechanisms, simplifying the controller's design. Then, the basic principles of the uncertainty and disturbance estimator (UDE) are introduced. The small-signal model of the dual active bridge (DAB) converter is applied to the UDE to minimize output voltage error by enabling the controller to directly regulate the shift ratio. Finally, this article discusses the application and effectiveness of the uncertainty and disturbance estimator (UDE) in the simulation and control of dual active bridge (DAB) converters. A series of experimental comparative studies are conducted, demonstrating that this scheme offers significant advantages in suppressing system uncertainties and disturbances.

An Improved Near-State Pulse-Width Modulation with Low Switching Loss for a Permanent Magnet Synchronous Machine Drive System

Common-mode voltage (CMV) leads to the shaft voltage and shaft current by coupling the capacitor network in the permanent magnet synchronous machine (PMSM), which affects the reliability of the whole motor drive system. Based on the low-CMV modulation strategy for the PMSM drive system, this paper proposed an improved near-state pulse-width modulation (NSPWM) on switching loss. First, the generation mechanism for the switching signals of NSPWM was analyzed, and it was observed that there exists one phase of switches in an inactive state for every sector. Then, to reduce the switching loss of the NSPWM, this paper proposed an improved NSPWM modulation strategy based on power factor angle to adjust switching action, which ensures the switching tubes that have the biggest conduction current have no switching action. In addition, the switching loss analytic formula of the NSPWM was derived to prove the correctness of the proposed method for optimizing switching loss. Finally, the proposed modulation strategy was carried out in the simulation and experimental platform. Under the premise of good steady and dynamic performance, the results show that the proposed modulation strategy has less switching loss.

Intelligent Light Emitting Diode Flashing Supplementary Lighting Control Design and Its Big Data Illumination Analysis

Considering the inherent advantages of the Light Emitting Diode (LED) in the field of illumination, this work designs an intelligent supplementary lighting system using LED as the light source. Combining microcontroller and electronic circuit theory, the circuit is built with the microcontroller PIC16F873 as the core control chip. The system utilizes an external 220 V AC-20 V DC conversion power supply, hence operating on a 20 V DC power source. The system consists of four hardware parts: the onboard power supply uses TI-produced TPS54331 as the control chip to achieve voltage conversion; the external signals (flashing and burst flashing signals) are isolated from the microcontroller through an optocoupler circuit; the PWM pulses output from the microcontroller’s RC1/CCP2 pins drive the corresponding switching tubes to achieve the flashing function; the flashing synchronization signal is output externally after optocoupler isolation, and its synchronous output with the flashing signal is achieved through an optocoupler after LED conduction; the circuit is established using TI-produced differential bus transceiver SN65LBC184D to convert the external 485 differential signal to the level signal required by the microcontroller. In the experiment, after completing the hardware design, connecting the LED panel, and debugging the test program, it is found that the designed lighting system has a good supplementary lighting effect. According to the PWM output waveform, the flashing effect meets the design expectations. The Hadoop big data computing platform is introduced. Simulation testing reveals that under no backlight conditions, the system achieves an illumination intensity of around 20 klx at a distance of about 10 meters. With backlight conditions, the system maintains an illumination intensity of around 1.5 klx at a distance of about 10 meters. Further calculations are performed to analyze the variation in foot traffic within the test area’s illumination over 24 hours. The total illumination intensity during different time intervals is compiled, confirming that the system can autonomously adjust the illumination intensity of the area based on changes in foot traffic.

Implementation and Analysis of an Efficient Soft-Switching Battery Wireless Charger with Re-Configurable Rectifier

To significantly reduce switching loss of the high frequency inverter in battery wireless charger (BWC), improve the soft-switching stability and system reliability, a novel soft-switching BWC with low loss auxiliary network and re-configurable rectifier is presented. The presented soft-switching BWC can implement the smooth switching between constant current mode (CCM) and constant voltage mode (CVM) without frequency switching and relays, which is beneficial to enhancing the system stability. With the help of a novel low energy consumption auxiliary circuit, the power switch tubes in the H-bridge inverter can implement zero-voltage soft switch-ON and zero-current soft switch-OFF in the full range, completely eliminating switching loss of the inverter. The proposed scheme can enhance the system efficiency while refraining from the soft-switching range limitation and soft-switching failure caused by the system parameter perturbation. Finally, a 1-kW soft-switching BWC principle prototype is developed to validate the effectiveness and correctness of the proposed scheme.

Fault‐tolerant control of current residual vector three‐phase four‐switch motor drive system based on MLD model

AbstractAiming at the problem of single‐phase switch tube open circuit fault in inverters, a current residual vector three‐phase four‐switch fault‐tolerant control strategy based on the mixed logic dynamic (MLD) model of permanent magnet synchronous motor (PMSM) drive system is proposed. Firstly, the MLD and three‐phase four‐switch mathematical models of the motor drive system are established and a calculation method of DC bus capacitance is proposed. Secondly, to improve the dynamic performance of the motor, an improved vector control based on the MLD model is proposed. Finally, by setting the threshold and dividing the area of the current residual vector, the accuracy of inverter fault diagnosis is improved, and the fast and smooth switching of the drive system after the fault is realized. Simulation and experimental results show that this strategy can effectively reduce the influence of calculation error and system noise, and has strong robustness for the change of motor speed and load.

Research on MLD Modeling and Predictive Control of Magnetically Coupled Resonant Bidirectional WPT System

The recent studies on magnetically coupled resonant bidirectional wireless power transfer (MCR-BWPT) systems disregard the challenges posed by nonlinearity, discrete switching action, and hybrid properties within the system. This research focuses on the D-LCL resonant compensation topology MCR-BWPT system. The switch tube’s switching state dictates the division of various working modes and the determination of the switching conditions between them. The coupling relationship between the continuous dynamic characteristics of the system and discrete events and the constrained conditions of the system are derived. The Hybrid System Description Language (HYSDEL) is used to build the Mixed Logic Dynamic (MLD) model of the system. The MLD model is employed as the prediction model, and the hybrid model predictive controller of the MCR-BWPT system is constructed according to the quadratic performance index. Finally, to verify the accuracy of the MLD model and the feasibility of the control strategy, the simulation model of the MLD model is established in MATLAB/Simulink. The study’s findings show that, in terms of response time at system startup and power fluctuation suppression, the approach put forward in this research performs better than both the conventional bilateral dual-phase-shift control strategy and the PQ-based bilateral power control strategy. The MCR-BWPT system can operate more steadily now that PQ’s bidirectional power control technique is in place. The system’s forward and reverse transmission efficiency is increased by 0.29% and 0.32% compared to the conventional bilateral dual-phase-shift control approach; the increases are 0.28% and 0.09%, each compared to the bilateral power control strategy based on PQ.

Model Predictive Control Strategy Based on Loss Equalization for Three-Level ANPC Inverters

Targeting the issue of high losses of individual switching tubes in Neutral-Point Clamped (NPC) three-level inverters, an Active Neutral-Point Clamped (ANPC) three-level inverter is used, and a model predictive control strategy using the loss equalization of the inverter is proposed. This method organizes and analyzes multiple zero-state current pathway commutation modes and adds mode three under the original two commonly used zero-state commutation modes. On this basis, the three modes are flexibly switched by model predictive control, and the output is optimized according to the value function for the space vector in each operation, while the midpoint voltage control is added to the value function. The simulation results suggest that the recommended strategy in this study may effectively realize the loss equalization control and midpoint voltage control of the ANPC inverter, which improves the operation efficiency of the electromechanical actuator.

Modeling and simulation of three-level DC/DC converters of high voltage wide range PI control

The three-level DC/DC converter is widely used in various applications, including electric vehicle charging stations, portable power supplies, and photovoltaic power generation. The mathematical models of input voltage, output voltage, and duty cycle of IGBT switch tube are established by analyzing the different operating modes of IGBT switch tube under PWM control. To validate the accuracy of the mathematical models, a simulation model can be built in MATLAB virtual environment, and a proportional-integral (PI) controller can be utilized to implement a hybrid closed-loop control strategy, where the current serves as the inner loop and the voltage as the outer loop. Such a control scheme will help to verify the feasibility of the mathematical models.

Analysis of Power Transmission Characteristics of a Novel Secondary Side LCD Series Forward Converter

A novel secondary-side LCD series forward converter is proposed, and the power transmission characteristics of the excitation inductance of the proposed converter under different modes are analyzed. By analyzing the relationship between the transmission power of forward branch and additional branch and excitation inductance, it is concluded that when the excitation inductance Lm works in CCM (continuous conduction mode), the transmission power of forward branch and additional branch has nothing to do with the value of excitation inductance. When the excitation inductance Lm works in DCM (discontinuous conduction mode), the transmission power of forward branch increases with the increase of excitation inductance, while the transmission power of additional branch decreases with the increase of excitation inductance. At the same time, the influence of power distribution on the efficiency of transformation topology is explored, and the relationship between the transmission power of the forward branch and the current stress of the switching tube was derived, and the parameter design method of magnetic element is put forward. Finally, the circuit model of the novel secondary side LCD series Forward converter is established, and the experimental results verify the correctness of the theoretical analysis and the feasibility of the parameter design method.

Design and development of single-phase inverter for locomotives based on SVPWM

For locomotive in high-power inverter power supply output efficiency is low, the level is not stable, push-pull circuit before the switch tube of high pressure, low utilization rate of the original winding transformer problem, designed and developed a kind of single phase inverter power supply based on SVPWM control. The inverter is designed with a modular structure with a rated power of 4KW, which is used to supply power to the cab electrical apparatus and auxiliary air compressor at both ends of the locomotive. It is composed of a filter circuit, a front-end boost control drive circuit, a full-bridge DC boost circuit, an inverter control circuit, a voltage and current sampling circuit, a back-end full-bridge inverter circuit and a protection circuit. The front stage of the inverter adopts a full bridge chopper circuit topology, while the rear stage achieves SVPWM control through the Vacon NXS control box. Finally, a power supply prototype was produced through simulation verification, and the results showed that the designed power supply met the design requirements.

Study on CLLC-SMES System based on the Passivity Control Strategy

Background: SMES systems as power compensation devices can effectively improve the transient stability of the power system. Due to the nonlinear and strongly coupled characteristics of the compensation device, an effective transfer function cannot be established, such that the traditional PI control by the linearization cannot accurately describe the complex nonlinear system. Objective: In this paper, a passive control strategy is introduced for the SMES System based on CLLC resonant converter to solve the problems that the traditional PI control cannot accurately describe the complex nonlinear system and the parameters’ settings are complicated. Methods: First, according to KVL and KCL, the mathematical model of the SMES system based on the CLLC resonant converter in the (d, q) coordinates is derived and established. Second, based on passive control theory, the port-controlled dissipation Hamiltonian model of CLLC-SMES is given. Third, combined with the passivity of SMES, the energy equation is established and the active and reactive power are analyzed respectively for the balanceable expectation, and then the energy equation is solved to obtain the drive signal of the switch tube. Fourth, the stability of the passive controller is verified by the Lyapunov equation, and the feasibility of the passive control strategy of CLLC-SMES is verified by simulation. Results: The results show that compared with the traditional PI control strategy, the power compensation system based on the passive control strategy does not need to establish the transfer function and the parameters are simple to adjust. Conclusion: It can not only track the active and reactive power commands quickly and accurately but also improve the transient state of the power system effectively.

SWISS rectifier structure sector boundary current distortion suppression based on multi‐step predictive control

AbstractThe SWISS rectifier is a three‐phase BUCK type Power Factor Correction rectifier with the advantages of adjustable output full voltage range, low voltage stress in the back stage devices, and high efficiency. However, because the voltage ripple of the input filter capacitor will cause the input current deviation, the input current of the SWISS rectifier will produce distortion at the sector boundary, which will affect the system performance. To this end, a multi‐stage predictive model method based on the spherical algorithm is presented. By predicting the grid‐side capacitor voltage and the input current state of the rectifier, the harmonic injection network switching tube is controlled in advance to supplement the grid‐side capacitor voltage, so that the grid‐side capacitor voltage approximately tracks the input voltage. Meanwhile, considering the current step that may be generated after the current distortion returns to normal, which leads to the resonance problem with the pre‐stage filter, this problem is incorporated into the value function and damping is optimized according to the feedback value. Finally, a 10‐kW SWISS rectifier on the SIMULINK platform is used to verify the feasibility of the new control method.

Research on Grid-Connected Control Strategy of Photovoltaic (PV) Energy Storage Based on Constant Power Operation

In order to effectively mitigate the issue of frequent fluctuations in the output power of a PV system, this paper proposes a working mode for PV and energy storage battery integration. To address maximum power point tracking of PV cells, a fuzzy control-based tracking strategy is adopted. The principles and corresponding mathematical models are analyzed for the three-phase voltage PWM converter and bidirectional DC/DC converter, while feedforward decoupling double closed loop, constant power (PQ), and constant voltage charge/discharge control strategies are proposed. Space vector pulse width modulation (SVPWM) technology is utilized to generate power switching tube driver signals. Finally, a simulation model is developed in MATLAB/Simulink for system analysis. The results demonstrate that the proposed method enables constant grid-connected power generation and constant voltage charging of the energy storage battery when the PV cell’s power generation exceeds that of the grid. When insufficient solar power generation occurs, both the PV system and energy storage battery work together to achieve constant grid-connected power.

Hybrid Data-Mechanism Modeling for Power Loss of a Boost Converter

Parameter design is the premise to ensure the optimal performance of power electronic converters, which depends on the accuracy of the established model. However, there is still many issues for improvements in modeling methods for the parameters design of power electronic converters. Due to the lack of key mechanism and the uncertainty of parameters, the existing modeling method shows poor accuracy or efficiency. In order to simplify the process and improve the accuracy of the existing modeling method, this paper proposes a hybrid data-mechanism modeling (HDMM) method for power loss of a typical power electronic converter, Boost converter, which is with UC3842 control chip. Based on the main loss from inductor, switch tube, diode and sampling resistance, the mechanism power loss modeling of Boost converter is built. Besides, the artificial neural network (ANN) is used to learn from the sampled data and train the data-driven model. To improve the accuracy of the mechanism model, the HDMM for power loss of Boost converter is established by modification of data-driven model with limited data. Through the proposed HDMM method, the mechanism modeling method and data-driven method are well combined and the HDMM has the advantage of high accuracy and strong generalization. In the end of this paper, feasibility and accuracy of the proposed HDMM method have been verified by hardware experiments.

A Gate Drive Circuit for Dual N-type H-bridge Power Transistors

A new grid driver of a high-side N-type switch tube is designed, which is easy to integrate. The circuit has the characteristics of low cost and fast speed and solves the problem of the unstable output voltage of a high-side switch tube when a low-side switch tube is not working in a traditional bootstrap circuit. The power supply voltage of the circuit is 30 V, including the voltage bias module, a high-level voltage shift circuit module, and a charge pump module. It can meet the driving requirements of a large size and high-side N-type switch tube. In this study, the 0.18 μm MGN process was used for design and simulation. The simulation results show that the grid driver has good driving ability.

The Scheme of Movable DC Ice Melting Device Based on the Engine-Generator Topology

In this article, an entire scheme of DC ice-melting devices based on the engine-generator topology is proposed to solve the problem of poor portability caused by the current devices. It is found that the engine-generator topology suffers from a power mismatch when starting with load, which may eventually lead to starting failure. A soft-start strategy is proposed to control the power required by the load by controlling the duty cycle of the switching tube to achieve real-time power matching. Compared with the most popular phase-controlled rectifier DC ice melting device, the entire scheme of the device is proposed, which not only achieves continuous voltage and current adjustment but also effectively reduces the ripple of the output and control complexity. The feasibility of the proposed soft-start strategy and the entire scheme of the device is verified by simulation results.