Design for Motor Controller in Hybrid Electric Vehicle Based on Vector Frequency Conversion Technology

Motor and its control technology are one of the main components of Hybrid Electric Vehicle (HEV). To meet HEV's fast torque response, vector control algorithm based on rotor flux-oriented and simulation model is concerned and modular designs for controller's hardware and software are presented in the paper in order to build a platform to achieve the vector control of asynchronous induction motor. Analyze the controller's electromagnetic compatibility, introduce the corresponding antijamming measures to assure the normal operation of the electromagnetic sensitive devices such as CAN bus; experiment proves that the measure is practical and feasible. On the basis of the control logic correct, such as improving CAN bus communication reliability, assuring power-on sequence and fault treatment, carry on the motor bench experiment, test its static properties, and adjust the controller parameters. The experimental results show that the designed driving system has the performance of low speed and high torque, a wide range of variable speed and high comprehensive efficiency

Optimization of Hybrid Electric Bus Driving System's Control Strategy

AbstractThe popularity of hybrid electric bus (HEB) is a most realistic way to solve emission and energy problem currently, so it's important to improve the HEB's fuel economy and efficiency. This paper optimizes the HEB's driving system to satisfy the conditions of this city. We applied the fuzzy logic control of modern control theory to the driving system's control of parallel-HEB, and optimized the driving system's control strategy of this city's hybrid bus based on this theory. We adopted the ADVISOR2002 for HEB's driving system's re-development, namely established the driving system's simulation model for this city's hybrid bus, then we tested the simulation model on the HEB urban driving cycle which had been developed in our preparatory work. The simulation results of our new control strategy and the simulation model proposed in this paper can further enhance the fuel economy and improve the driving system's efficiency, thus the results provided important reference for the upgrading of this type HEB's driving system

An Empirical Study of Catastrophic Forgetting in Large Language Models During Continual Fine-tuning

Catastrophic forgetting (CF) is a phenomenon that occurs in machine learning when a model forgets previously learned information as it learns new information. As large language models (LLMs) have shown excellent performance, it is interesting to uncover whether CF exists in the continual fine-tuning of LLMs. In this study, we empirically evaluate the forgetting phenomenon in LLMs' knowledge, from the perspectives of domain knowledge, reasoning, and reading comprehension. The experiments demonstrate that catastrophic forgetting is generally observed in LLMs ranging from 1b to 7b. Furthermore, as the scale increases, the severity of forgetting also intensifies. Comparing the decoder-only model BLOOMZ with the encoder-decoder model mT0, BLOOMZ suffers less forgetting and maintains more knowledge. We also observe that LLMs can mitigate language bias (e.g. gender bias) during continual fine-tuning. Moreover, we find that ALPACA can maintain more knowledge and capacity compared with LLAMA during the continual fine-tuning, which implies that general instruction tuning can help mitigate the forgetting phenomenon of LLMs in the further fine-tuning process

The complete mitochondrial genome of Xizicus (Haploxizicus) maculatus revealed by Next-Generation Sequencing and phylogenetic implication (Orthoptera, Meconematinae)

Xizicus Gorochov, 1993, the quiet-calling katydid, is a diverse genus with 68 species in world, which includes more than 45 species in China, has undergone numerous taxonomic revisions with contradicting conclusions. In this study the complete mitochondrial genome of Xizicus (Haploxizicus) maculatus collected from Hainan for the first time was sequenced using the Next-Generation Sequencing (NGS) technology. The length of whole mitogenome is 16,358 bp and contains the typical gene arrangement, base composition, and codon usage found in other related species. The overall base composition of the mitochondrial genome is 37.0 % A, 32.2 % T, 20.2 % C, and 10.6 % G. All 13 protein-coding genes (PCGs) began with typical ATN initiation codon. Nine of the 13 PCGs have a complete termination codon, but the remaining four genes (COI, COIII, ND5, and ND4) terminate with an incomplete T. Phylogenetic analyses are carried out based on the concatenated dataset of 13 PCGs and two rRNAs of Tettigoniidae species available in GenBank. Both Bayesian inference and Maximum Likelihood analyses recovered each subfamily as a monophyletic group. Regardless of the position of Lipotactinae, the relationships among the subfamilies of Tettigoniidae were as follows: ((((Tettigoniinae, Bradyporinae) Meconematinae) Conocephalinae) Hexacentrinae). The topological structure of the phylogeny trees showed that the Xizicus (Haploxizicus) maculatus is closer to Xizicus (Xizicus) fascipes than Xizicus (Eoxizicus) howardi

The Evolutionary Patterns of Genome Size in Ensifera (Insecta: Orthoptera)

Genomic size variation has long been a focus for biologists. However, due to the lack of genome size data, the mechanisms behind this variation and the biological significance of insect genome size are rarely studied systematically. The detailed taxonomy and phylogeny of the Ensifera, as well as the extensive documentation concerning their morphological, ecological, behavioral, and distributional characteristics, make them a strong model for studying the important scientific problem of genome size variation. However, data on the genome size of Ensifera are rather sparse. In our study, we used flow cytometry to determine the genome size of 32 species of Ensifera, the smallest one being only 1C = 0.952 pg with the largest species up to 1C = 19.135 pg, representing a 20-fold range. This provides a broader blueprint for the genome size variation of Orthoptera than was previously available. We also completed the assembly of nine mitochondrial genomes and combined mitochondrial genome data from public databases to construct phylogenetic trees containing 32 species of Ensifera and three outgroups. Based on these inferred phylogenetic trees, we detected the phylogenetic signal of genome size variation in Ensifera and found that it was strong in both males and females. Phylogenetic comparative analyses revealed that there were no correlations between genome size and body size or flight ability in Tettigoniidae. Reconstruction of ancestral genome size revealed that the genome size of Ensifera evolved in a complex pattern, in which the genome size of the grylloid clade tended to decrease while that of the non-grylloid clade expanded significantly albeit with fluctuations. However, the evolutionary mechanisms underlying variation of genome size in Ensifera are still unknown

The OpenMolcas Web: A Community-Driven Approach to Advancing Computational Chemistry

The developments of the open-source OpenMolcas chemistry software environment since spring 2020 are described, with a focus on novel functionalities accessible in the stable branch of the package or via interfaces with other packages. These developments span a wide range of topics in computational chemistry and are presented in thematic sections: electronic structure theory, electronic spectroscopy simulations, analytic gradients and molecular structure optimizations, ab initio molecular dynamics, and other new features. This report offers an overview of the chemical phenomena and processes OpenMolcas can address, while showing that OpenMolcas is an attractive platform for state-of-the-art atomistic computer simulations

Control Method of the Dual-Winding Motor for Online High-Frequency Resistance Measurement in Fuel Cell Vehicle

The dual-winding motor drive has recently been proposed in the field of fuel cell vehicles due to its performance and high robust advantages. Efforts for this new topology have been made by many researchers. However, the high-frequency resistance measurement of a proton exchange membrane fuel cell based on dual-winding motor drive architecture, which is important for water management to optimize the lifespan of fuel cells, was not employed in earlier works. In this paper, a new control method of the dual-winding motor is proposed by introducing a dc input current control to realize high-frequency resistance measurement and normal drive control simultaneously, without using extra dc-dc converter. On the basis of the revealed energy exchange principles among electrical ports and mechanical port of the dual-winding motor, the load ripple caused by high-frequency current perturbation is optimized based on the q-axis current distribution between two winding sets. The decoupling control algorithm for the coupling effect within and across windings is also discussed to improve the dynamic response during high-frequency resistance measurement. Finally, simulation results verify the effectiveness and improvement of the proposed method. Fast Fourier transform results indicated that the total harmonic distortion of the dc input current was reduced from 22.53% to 4.47% of the fundamental, and the torque ripple was suppressed from about ±4.5 Nm to ±0.5 Nm at the given operation points

Steady-State Control of Fuel Cell Based on Boost Mode of a Dual Winding Motor

In recent years, a dual winding motor drive has been proposed in the field of fuel cell vehicles due to its advantages of good performance and high robustness. This new topology and its basic control method have been widely investigated. However, the previous research has not considered the current dynamic property of a fuel cell when studying the power sharing control method, but this is an important research objective for fuel cell durability. Considering the current change principle of a fuel cell, an optimal steady-state control method based on a new dual winding motor architecture boost charging is proposed to optimize the fuel cell life. In addition, in view of the current circulation problem of the fuel cell side winding in the boost mode, a Bang-Bang-PI control algorithm with a relatively constant reference value is proposed to realize the current sharing control. On this basis, the optimized control of the output current ripple of the fuel cell is realized to ensure the steady-state of the proton exchange membrane fuel cell (PEMFC). Finally, the results show that this method can control the stability of the fuel cell efficiently

Mitochondrial genome of a brachypterous species in Meconematinae: Acosmetura nigrogeniculata and its phylogenetic implication

Acosmetura nigrogeniculata (Liu and Wang, ) is a brachypterous species in Meconematinae, which is only distributed in China. In this study, the complete mitochondrial genome of A. nigrogeniculata was determined and annotated. The 16,271 bp circular genome contained 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and one control region. The overall base composition was 36.4% A, 34.8% T, 18.4% C, and 10.5% G, exhibiting obvious anti-G and AT bias (71.2%). The general genomic characters including nucleotides composition, gene arrangement, and codon usage were similar to those of other Meconematinae species. Phylogenetic analysis of all nine Meconematinae species indicated that the newly sequenced species were clustered closely with the brachypterous species Pseudosmetura snjiensis

Research on Sensorless Control of Permanent Magnet Synchronous Motor for Electric Vehicle

Motor speed can’t change suddenly during the operation of motor because of inertia. In the short process of motor being not driven by motor controller, the operation of motor can be thought of as a uniform motion process. Making use of this property, it can be estimated next or next several cycles by measuring previous one or several cycles of motor. So the motor speed can be Figured out according to measured cycles. The phase angle can be estimated by zero crossing point of induced electromotive force produced in the running process of motor. Then the magnetic field position is estimated, and the angle measured by position sensors can be replaced by estimated angle. At last, bench test proves that this method can improve the reliability and safety of the motor control and has a good fault tolerance so as to be used as an auxiliary control method in motor control of electric vehicle and realize multi-mode control. DOI : http://dx.doi.org/10.11591/telkomnika.v12i2.400