Current Balance Control Research Articles

A Modulation Method With Current Zero-Crossing Distortion Elimination and Voltage Balance Control for the RSHMC Converter

A Modulation Method With Current Zero-Crossing Distortion Elimination and Voltage Balance Control for the RSHMC Converter

A Hybrid Multiobjective Control Strategy Based on Combination of Modulated Model Predictive Control and Phase‐Shifted Modulation for a Unidirectional Five‐Level Rectifier

ABSTRACTThe unidirectional multilevel rectifier has immense potential in high‐power medium‐voltage industrial applications. This paper proposes a multiobjective control method based on the combination of optimal‐vector‐pair modulated model predictive control (OVP‐M2PC) and a phase‐shifted modulation strategy for a unidirectional five‐level rectifier. This strategy takes both of the inductor current tracking and capacitor voltage balancing as the control objectives. First, an optimal vector pair is determined based on the AC‐side current variation rate, and then, through combining the calculated action duration of OVP with carrier phase‐shifted modulation, inductor current tracking is achieved. Second, capacitor voltage balancing control is carried out by compensating for the duty cycles which also decouples the input current tracking and output capacitor voltage balance control. Compared with traditional FCS‐MPC, under the proposed control strategy, complex cost function calculation and weighting factor tuning are not required, which much reduced computational burden. Multiobjective control is achieved with better performance in both steady‐state and dynamic conditions. The superiority of the proposed strategy over traditional FCS‐MPC are validated through simulations and hardware experiments.

Comprehensive Analysis and Reconstruction of Sensor Faults in Interleaved Buck Converters Using Sliding Mode Observers

This paper presents a fault signal reconstruction method for current sensors in an interleaved buck DC–DC converter, utilizing a sliding mode observer (SMO). A filter bank is used to design the observer within an extended-order system, effectively treating sensor faults as actuator faults, which enables precise estimation of the fault signal. Thus, the proposed approach allows for the identification of the faulty sensor and supports the implementation of fault-tolerant strategies. The paper provides an in-depth analysis of current sensor faults, verifies their impact on current balancing control, and demonstrates the challenge of achieving error-free current estimation in one phase using observers. A comprehensive set of simulation results is carried out, validating the method’s effectiveness and showing a strong correlation with theoretical principles.

Research on Cascaded On‐Board DC/DC Converter Based on Three‐Phase Interleaved LLC

ABSTRACTThe on‐board DC/DC converter proposed in this research consists of a Buck converter and a three‐phase interleaved LLC resonant converter. This paper analyzes the average current and output current ripple characteristics of the rear‐stage converter in addition to explaining the topology and working principles of the front‐stage Buck converter and the rear‐stage three‐phase interleaved LLC resonant converter. To establish a single‐phase fundamental equivalent circuit for the rear‐stage converter, apply the fundamental wave analysis method, and it is essential for comprehending the impact of relevant system parameters on voltage gain characteristics and resonant operating regions. Conducting research on the two‐stage on‐board DC/DC converter's control strategy involves establishing small‐signal circuit models for both front and rear stage converters, derivation of parameters for double closed‐loop control, and determination of the control strategy employing phase‐shifted current sharing for the rear‐stage converter in cases where significant tolerance exists in resonant components. The simulation for a two‐stage on‐board DC/DC converter results indicates that under various conditions of resonant component tolerance, the converter is capable of achieving balanced phase currents and demonstrates minimal output current ripple prior to capacitor filtering. A 1.5‐kW experimental prototype has been fabricated, and the experimental findings indicate that the output voltage remains stable at 13.8 V despite fluctuations in input voltage. The highest efficiency of the prototype is about 96.27%, and the utilization of phase‐shifting current balancing control results in a notable reduction in output current ripple. This provides more evidence that the design of a two‐stage on‐board DC/DC converter is correct.

A hybrid inductor‐current sensor with fast response and high accuracy using online calibration for high‐frequency BUCK DC‐DC converters

AbstractThis paper introduces a hybrid inductor‐current sensor with fast response and high accuracy using online calibration for 25 MHz BUCK DC‐DC converter. The proposed inductor‐current sensor combines the high accuracy of the senseFET sensing method with the lossless and real‐time response characteristics of the RC filter technique. Comparing to exist techniques, the proposed calibration scheme can make filter coefficient converge even in unsteady state, which improve its effectiveness in practical application. Moreover, the proposed inductor‐current sensor utilizes sample‐based senseFET‐based current sensing to offer calibration reference, which avoid the use of high bandwidth amplifier. Digital current balance control is seamlessly integrated into the 25 MHz 2‐phase digital adaptive time‐controlled (AOT) BUCK DC‐DC converter through the utilization of the proposed hybrid inductor‐current sensor. The 2‐phase BUCK DC‐DC converter is implemented in a standard 0.18‐µm CMOS process. After online calibration, proposed hybrid inductor‐current sensor outputs a full‐wave waveform with high accuracy and low propagation delay of only 9 ns in post‐layout simulation.

Current ripple optimization design of DC/DC converter

Abstract Renewable energy has the advantages of renewability and high temperature and has great potential for development, but its instability limits its large-scale promotion. Aiming at the stable operation of the new energy power system and ensuring the safe and reliable operation of the power grid, this project defines the basic topology of the variable multiple DC/DC converter according to the idea of switching circuit parallel factor or reducing ripple under each duty cycle. Secondly, the system structure under the boost mode is modeled, and the system is optimized by the combination of a single closed-loop current balance and duty cycle feedforward control. Finally, the model is simulated, and the results show that the method is correct and reasonable.

Current Balancing Control Method With Reduced Number of Current Sensors for Interleaved LLC Converters

Current Balancing Control Method With Reduced Number of Current Sensors for Interleaved LLC Converters

Passivity-Based Control and Current Balance Control of a Current-Source Pulse-Width-Modulation Rectifier

To improve the static performance, dynamic performance, and current balance of a current-source PWM rectifier with multi-modules, a comprehensive control method with passivity-based control and current balance control is proposed in this paper. Current balance control, which is based on AC voltage sequencing, has the advantages of being easy to implement and not being limited by the number of modules. Mathematical modelling, controller design, and simulation verification were conducted successively, and the results show that the comprehensive control method has a low current impact and high power quality. At the same time, module currents are well balanced, even under external disturbance, when using current balance control.

Output Power Capacity Improvement Based on Three-Phase Current Balance Control for the Doubly Salient Electromagnetic Generator System

The doubly salient electromagnetic generator (DSEG) has the advantages of flexible control, high robustness, and low cost. Since multiple stator poles share a common set of field windings, the magnetic circuit of each phase is asymmetrical, which limits the output performance of the DSEG. The three-phase current balance control for the DSEG system was proposed. By investigating the current waveform under the angular position control (APC), a three-phase current prediction method was proposed. The conduction angle of the power switches in the active rectifier was predicted to make the three-phase current balanced. Based on the analysis and experiment, the current waveform was further analyzed, and the effectiveness of the three-phase current balance control was verified. Compared with the APC method, the output power capacity was improved using the three-phase current balance control under a limited winding current density. The maximum potential of the DSEG was explored, and the electromagnetic load capacity of the DSEG was fully released.

Ring Laser Gyros: Improving Precision and Accuracy Through Soft-Core Processor-Based Active Current Balance Control Approach- Simulation and Implementation Results

In this article, we intend to demonstrate on digital active current control in ring laser gyros (RLG). The specific source errors that effect the performance of laser gyro is discussed. This work proposes a system of digital detection and control system to address deficiencies of the conventional analog circuits. The hardware framework is constructed using the Field Programmable Gate Array (FPGA) and the required analog interface, which incorporates driving and acquisition circuitry for the specific physics of gyros. The software flow is provided in full and uses the parallel PI (proportional-integral) control algorithms. The outcomes demonstrate that the precision of anode currents are accurately controlled within ±0.1µA along with cathode voltage, demonstrating that the performance of the digital system is superior to that of analog circuits, which will be very beneficial for the laser gyro application. The simulation results prove that the proposed approach has good result of balancing anode currents, meanwhile, it makes the sensor a good dynamic performance. In both anodes, the experimental findings are contrasted with balanced and unbalanced currents. The optimal constant current is obtained from the remarkable agreement between simulated and experimental results.

Partially Isolated Multiport Converter With Automatic Current Balancing Interleaved PWM Converter and Improved Transformer Utilization for EV Batteries

Multiport converters (MPCs) that can regulate multiple input/output ports have been proposed to reduce the converter count in electric vehicle battery systems consisting of multiple batteries (12-V, 48-V, and high-voltage batteries). Conventional MPCs consist of an interleaved PWM converter and DAB converter, and an active current balancing control is indispensable for the interleaved converter. Furthermore, the transformer utilization unavoidably decreases because switches are driven with a nominal duty cycle of 0.75 for 48-/12-V batteries. This article proposes a novel MPC with an automatic current balancing capability and improved transformer utilization. A flying capacitor (FC) is added to the interleaved PWM converter to automatically balance inductor currents. The added FC also allows operations with a nominal duty cycle of 0.5 for 48-/12-V batteries, improving the transformer utilization. The experimental verification tests using a 1-kW prototype demonstrated the automatic current balancing capability, improved transformer utilization, and flexible power exchange among three batteries.

Sensorless Current Balancing Control for Interleaved Half-Bridge Submodules in Modular Multilevel Converters

A new state-observer-based current balancing method for Modular Multilevel Converters with Interleaved half-bridge Sub-Modules (ISM-MMC) is presented in this article. The developed observer allows estimating currents through interleaved half-bridge legs in each submodule of ISM-MMC based only on arm current and submodule's capacitor voltage measurements. Then, the interleaved current balancing control uses the estimated currents to reduce the interleaved currents imbalance caused by upstream control actions. This technique minimizes the number of required current sensors in ISM-MMC, thereby reducing the converter's cost, weight, and volume. Capabilities of the proposed sensorless interleaved currents balancing control have been tested against standard parameter tolerances of the composing passive elements. In addition to that, a novel capacitor voltage balancing strategy for MMCs is developed. The new algorithm contains the main advantages of the classical sorting-based capacitor voltage balancing methods while providing an opportunity to decouple two balancing tasks of ISM-MMC, namely capacitor voltage and interleaved legs current balancing. The feasibility of the proposed methods is verified by extensive simulation and experimental tests on a laboratory prototype by the corresponding system response under the output characteristics variation and interleaved current control perturbation.

Gate Driver ICs with Closed-Loop Current Balancing Control for Parallel Connected IGBTs

Gate Driver ICs with Closed-Loop Current Balancing Control for Parallel Connected IGBTs

PV용 Interleaved Converter의 MPPT 및 전류 평형을 위한 DSP 기반의 제어기 설계 및 HILS 검증

This paper proposes a digital controller designed for maximum power point tracking control and phase current balancing control for PV system. A variable-step incremental conductance method is applied for maximum power point tracking. For phase current balance of the interleaved boost converter, an average current balance control method that reduces the control instability due to phase difference of the phase currents and A/D conversion is proposed. The ADC frequency is set to 2 times the switching frequency and 10 times the MPPT frequency. The designed controller is implemented in the TMS320F28335 DSP, and through PLECS simulation, the superiority of the proposed controller compared to the open loop and the proposed average current balance control method compared to the general control method are verified. Finally, the performance of the proposed controller under dc and sine wave insolation conditions is verified through HIL-Simulation.

A bidirectional three-level interleaved DC-DC converter for an electric vehicle charging station operating in a wide range of battery currents and voltages

Charging an Electrical Vehicle (EV) is a process dependent on the specs of their battery in each car with the charger being custom designed. This means that designing the converter for a general EV charging station is very challenging because it must accommodate a wide variety of currents/voltages/powers whilst maintaining a high conversion efficiency and low cost/size. To minimise the size of the magnetics, this paper proposes the use of both multilevel and interleaved technologies to easily support load voltage/current/power scale up. A 3-level flying capacitor converter topology usually deployed in DC/AC application is proposed to be integrated in a 2-channel interleaved implementation where each bidirectional three-level interleaved (B3LI) converter leg switches only half the load current and half the main DC source voltage. The system controller is equipped with phase current balancing and capacitor voltage equalisation control to maintain the system stability along with phase shedding control to reduce losses during low power operation. Simulations are implemented in PLECS software to validate the expected performance and operation of the proposed converter system.

Hybrid injection strategy of sub-module voltage ripple suppression for MMC under low frequency operation

Energy crisis and climate changes have brought great challenges to traditional power generation and transmission. Nowadays, the power transmission system of VSC-HVDC attracts more and more attention. The reactive and active power can be separately controlled, which greatly improves the flexibility of power transmission. Moreover, the harmonic content of this system is extremely low. As an important topology of HVDC system, modular multilevel converters (MMC) have significant advantages. However, there is a problem of excessive circulating current between phases in MMC, which easily causes the fluctuation amplitude of the capacitor voltage in each sub-module to be extremely large, or even unstable. An improved method to suppress the circulating current is proposed in this paper. In order to balance the voltage of each capacitor, the average capacitor voltage control of the outer loop is used. Meanwhile, an independent controller of voltage balance and a controller of arm voltage balance are applied. In order to eliminate the circulating harmonics of currents, a controller of quasi-PR is adopted for the inner control loop. Then, a simulating model of MMC system was established to prove the effectiveness of the proposed method. Finally, an experimental prototype was built and the corresponding tested results are given. It is proved that the proposed method has obvious advantage on suppressing harmonic circulating current and capacitor voltage balance control.

Variable Voltage Variable Frequency Modular Multilevel AC/AC Converter With High-Frequency Harmonics Filtering Capability

This article proposes a variable voltage variable frequency modular multilevel ac/ac converter (VVVF-MMC) with a high-frequency isolation link, which can realize voltage and frequency conversion simultaneously with insulated-gate bipolar transistors (IGBTs) of the same rated voltage and current level. The parallel connection of multiple modules is realized by coupling reactors, which can realize large-scale voltage and current transformation and save volume. It combines parallel multiplexing and serial multiplexing technology of submodules (SMs) to increase the equivalent switching frequency, thereby canceling nonzero sequence high-frequency voltage and current harmonics, so it has good power quality in the steady-state. Under the improved carrier phase-shifted pulsewidth modulation (CPS-PWM) strategy, the pulse flip circuit can realize soft switching operation, thereby improving energy conversion efficiency. Furthermore, dc capacitor voltage balancing and parallel SM current balancing control strategies are designed. With the strong filtering ability, the proposed ac/ac converter can be used as the onshore converter station of fractional frequency offshore wind power system. Due to the advantages of small size and high efficiency, it also has broad application prospects in distribution networks and electric drive. Simulation and experimental results validate the effectiveness of the proposed converter topology.

A Basketball Technique Balance Control Technology Based on Ant Colony Algorithm

Aiming at the problems of low accuracy, poor stability, and effect of balance control in the current basketball skill balance control process, a basketball skill balance control method based on ant colony algorithm is proposed. The principle and characteristics of ant colony algorithm are analyzed, the mathematical model of ant colony algorithm is established, and the implementation steps of ant colony algorithm are given. According to the balance and stability control principle of basketball skills, this paper constructs the balance and stability control model of basketball skills. By establishing the knee-ankle-foot joint analysis model and using the ant colony algorithm, the basketball movement path is constructed. Through the fitness function, select the basketball motion path nodes and update the pheromone, obtain the relationship between the internal stress and displacement of the body under different force directions, and obtain the influence law of the effective knee joint stress with the varus and internal rotation, so as to achieve the balance and stability of the basketball skills sexual control analysis. The experimental results show that the proposed method has better stability and effect of basketball technique balance control and can effectively improve the accuracy of basketball technique balance control.

A Sensorless Current Balance Control Method for Interleaved Boost Converters Based on Output Voltage Ripple

In this article, a sensorless current balance control method for a multiple-phase interleaved boost converter is proposed. Balanced current can help an interleaved boost converter prevent imbalanced heat distribution and inductor saturation as well as improving the output voltage performance and overall system efficiency. This article analyzes the relationship equations between the periodic output voltage ripple and the phase current balance status. In the proposed method, the current sensor is eliminated, and only one voltage sensor on the output capacitor side is needed to monitor the output voltage information. The proposed sensorless current control method estimates the phase current distribution status according to the periodic output voltage peak ripple value and adjusts the phase current distribution status by changing the gate drive signal duty cycle of each phase MOSFET. To validate the proposed method, a PSIM simulation model and a two-phase interleaved boost converter test bench are set up, and the experiment waveforms verify the effectiveness of the proposed method.

Multiphase Open-End Winding Induction Machine Drive With the Floating Capacitor

A comprehensive control scheme is presented for the multiphase open-end winding induction machine drive topology, where the main inverter (MI) and floating inverter (FI) are supplied by a dc power source and a capacitor, respectively. Under the proposed method, the MI can work with the unity power factor, while the FI provides all the reactive power. Besides, the current waveform quality is improved by the harmonic suppression and current balance control. Moreover, the voltage of the floating capacitor is adjusted to keep the modulation ratio of the FI near one during the operation, which helps to reduce the switching losses of the system. Experimental results are presented to verify that the proposed control scheme is practical in controlling this open-end drive topology and suitable for expansion to high-phase-number occasions.