Running stabilization control of electric vehicle based on cornering stiffness estimation

In this paper, novel direct yaw moment control (DYC) with road condition estimation and anti‐slip control is proposed for electric vehicles. An inner‐loop observer controls the vehicle traction, and an outer‐loop observer stabilizes the yawing motion of the vehicle. An immeasurable parameter known as cornering stiffness is estimated from the detected yaw‐rate, steering angle, wheel speed and yaw moment observer output in real time. Thus, the accurate control input can be generated with the estimated parameters. The proposed adaptive control is compared with a conventional robust control method under dry and snowy terrain conditions. Experimental results show that the proposed control algorithm properly attenuates the yaw‐rate error. ©2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(4): 97–104, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20569     

The influence of mistuned motor parameters on vector control performance and on line slip frequency correction strategy for induction machine operated under one‐pulse PWM mode

In high‐power, high‐speed traction drive systems, the traction motor usually operates under one‐pulse PWM (pulse width modulation) mode (square wave) during high‐speed operation. The constant output voltage in this condition makes the traditional vector control inoperative anymore. In this paper, a modified vector control strategy using open‐loop current control instead of closed‐loop current control is proposed. The modified control strategy is specially designed for an induction motor operating under one‐pulse PWM mode. As the field orientation is greatly affected by the deviation in the parameters, the influence of mistuned rotor time constant and mutual inductance (which are regarded as the most important parameters for field orientation) on the performance of modified vector control is studied comprehensively, including the influence on estimated angle and amplitude of rotor flux, d/q‐axis voltage, and output torque. Subsequently, based on the comparison between the different methods, a new slip frequency correction strategy is proposed to maintain proper field orientation for the modified vector control. The new correction strategy is based on the q‐axis current component error. It is independent of the motor parameters and can be easily realized through minor calculations. The simulation and experimental results show that the proposed slip frequency correction strategy can not only eliminate rotor flux angle error in steady state but also effect rapid torque response during the transient process under one‐pulse PWM mode. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

A simple instant‐estimation method for time‐average quantities of single‐phase power and application to single‐phase power grid connection by inverter

This paper presents and analyzes a new simple instant‐estimation method for time‐average quantities such as rms values of voltage and current, active and reactive powers, and power factor for single‐phase power with the fundamental component of constant or nearly constant frequency by measuring instantaneous values of voltage and current. According to the analyses, the method can instantly estimate time‐average values with accuracy of the fundamental frequency, and estimation accuracy of the power factor is about two times better than that of voltage, current, and powers. The instant‐estimation method is simple and can be easily applied to single‐phase power control systems that are expected to control instantly and continuously power factor on a single‐phase grid by inverter. Based on the proposed instant‐estimation method, two methods for such power control systems are also proposed and their usefulness is verified through simulations. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 159(2): 34–43, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20236     

A new mapping method for phase estimation of single‐phase signals: A new generalization and new realizations of the DFT estimation method

This paper proposes and analyzes a new simple real‐time phase‐estimation method for single‐phase signals, which is based on a vector mapping theory of n‐dimensional to 2‐dimensional vectors. According to the analyses, the proposed mapping method can estimate instantly and properly the true phase of the signals that are contaminated by significant amplitude of noise and harmonics. The mapping method contains the conventional DFT method as a special case. In other words, it can be treated as a generalization of the DFT. Several simple realizations of the mapping method are also newly proposed as a single‐input and two‐output digital mapping filter in both nonrecursive and recursive forms. The recursive realization being able to decrease drastically computing load utilizes the normal form that is robust to finite word length effects. As an application of the proposed mapping method, inverter‐using power control system connected with a single‐phase grid is shown. All analytical results are verified by numerical experiments and the usefulness of the newly proposed mapping method is confirmed. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(1): 27–38, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20263     

Position and speed sensorless control system of permanent magnet synchronous motor with parameter identification

The model parameters of a permanent magnet synchronous motor (PMSM) are required for high‐performance control and a model‐based sensorless control. This paper proposes a sensorless control system of PMSM that does not need parametric information beforehand. The parameters of a PMSM drive system, including the inverter, are identified at standstill and under operating conditions. At first, the initial rotor position is estimated by a signal injection sensorless scheme in which the machine parameters are not required. After the initial position has been estimated, the resistance, including the on resistance of the IGBT, the voltage error caused by dead time in the inverter, and d‐axis and q‐axis inductances, are identified at standstill. After the motor starts by the signal injection sensorless control, the sensorless scheme changes to an extended EMF estimation scheme. The estimated parameters for the resistance, and daxis and q‐axis inductances are used in such sensorless control. The magnet flux‐linkage, which cannot be estimated at standstill, is identified under the sensorless operation at medium and high speeds. The effectiveness of the proposed method is verified by several experimental results. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(2): 68–76, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/ eej.20548     

Swing‐up and stabilization control of a cart– pendulum system via energy control and controlled Lagrangian methods

This paper addresses a swing‐up and stabilizing problem for a cart– pendulum system, which consists of a pendulum and a motor‐driven cart. Existing methods are based on the strategy of swing‐up of the pendulum by energy control methods, then switching the controllers to balance the pendulum when it approaches the upright position. The switching angle influences significantly control performance, so the pendulum might fall down if the angle is inadequately chosen. This paper proposes a swing‐up and stabilizing control method which makes it possible to determine an appropriate switching angle more arbitrarily. In addition to the energy control method for swing‐up, a stabilizing method based on controlled Lagrangians is adopted instead of a linear controller. The attractive domain of the closed‐loop system with this method can be known in advance and is wider than with linear controllers. In this way, our proposed control strategy overcomes the difficulty in choosing the switching angle of the controllers. An experimental result illustrates the effectiveness of the proposed method. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(4): 24– 31, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20534     

Target Path Tracking Method of Intelligent Vehicle Based on Competitive Cooperative Game

To improve intelligent vehicle drive performance and avoid vehicle side-slip during target path tracking, a linearized four-wheel vehicle model is adopted as a predictive control model, and an intelligent vehicle target path tracking method based on a competitive cooperative game is proposed. The design variables are divided into different strategic spaces owned by each player by calculating the affecting factors of the design variables with objective functions and fuzzy clustering. Based on the competitive cooperative game model, each game player takes its payoff as a mono-objective to optimize its own strategic space and obtain the best strategy to deal with others. The best strategies were combined into the game strategy set. Considering the front wheel angle and side slip angle increment constraint, tire side-slip angle, and tire side slip deflection dynamics, it took the path tracking state model was used as the objective, function and the calculation was validated by competitive cooperative game theory. The results demonstrated the effectiveness of the proposed algorithm. The experimental results show that this method can track an intelligent vehicle quickly and steadily and has good real-time performance.     

Evaluation and discussion of disturbance observer‐based anti‐slip/skip readhesion control for electric train

The improvement of adhesion characteristics is very important for electric trains. The drive system of electric trains must have fine anti‐slip and anti‐skid readhesion controls. In order to achieve the required adhesion, we have already proposed an anti‐slip/skid readhesion control system based on disturbance observer and sensorless vector control. Moreover, we have already applied the proposed method to actual electric multiple unit trains Series 205‐5000. In this paper, using the experimental results of Series 205‐5000 and the numerical simulation results, we evaluate the proposed anti‐slip/skid readhesion control system and confirm that the system has the desired driving wheel torque response. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 169(4): 55–64, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20834     

Prototype Experiments on a 1/32‐Scale Model Via‐Wheel Power Transfer Electric Vehicle

Electric vehicles (EVs) are expected to play a leading role in the changeover from fossil fuels to clean energy. However, EVs are currently not very popular, owing to their short cruising distance and long charging time. Wireless power transfer from the infrastructure to running EVs is expected to be the solution to these problems. Electric vehicle and electrified roadway (EVER) has been proposed as a wireless power transfer system for EVs while in motion. Via‐wheel power transfer (V‐WPT) is expected to be a wireless power transfer scheme for EVER. We designed and prototyped a 1:32 scale model of a V‐WPT system that consists of an RF inverter, an electrified roadway, a rectifier, and an EV with a dc motor. The output power of the prototype RF inverter was 5.9 W and the dc–RF conversion efficiency was 36.6%. The LC matching circuits for the V‐WPT were designed with two‐port conjugate matching because S₁₁ of the V‐WPT was intrinsically –0.06 dB. After matching, the S₁₁ value was reduced to –21.5 dB. The power transmission efficiency of the V‐WPT system was 75%. The RF–dc conversion efficiency of the rectifier was 62%. The total efficiency of the EVER system was 24.2%.     

Signal injection method without torque ripple based on maximum torque control frame

This paper presents a new signal injection method without torque ripple for sensorless controls of salient‐pole synchronous motors at low speeds. At low speeds, since the back electromotive force (EMF) including position information decreases, additional signals are injected to estimate position information of saliency. The torque ripple caused by the injections of signal currents can be represented by a cross product of a virtual flux and a differential current vector. An f‐axis of maximum torque control frame is defined to the direction of the virtual flux. Therefore, signal injection without torque ripple is realized by using the f‐axis current. In this paper, a signal injection method with f‐axis current is proposed, and the effects of the estimation error are discussed to apply the method for position‐sensor‐less controls. The proposed injection method allows us to flexibly design frequencies of the signal current. The validity of the proposed method and applicability to position estimation are confirmed by experimental tests. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Manufacturing and Control of a Variable Magnetic Flux Motor Prototype with a Mechanical Adjustment Method

A new structure and control method for a variable magnetic flux motor (VMFM) is proposed to achieve a high‐efficiency electric vehicle (EV) motor drive under a wide range of conditions. A VFMF prototype that was designed by considering the loss was manufactured and evaluated in an experiment. The prototype demonstrated low iron loss and sufficient max torque. Thus, the prototype can provide a high‐efficiency drive with low output, which is frequently the case for EVs. Map control enables a wide phase angle for the vector‐control drive of the VMFM under a changing magnetic flux. Thus, the VMFM provides a high‐efficiency drive under a wide range of conditions.     

Sensorless control of synchronous reluctance motors based on extended electromotive force model and inductance measurement

In this paper, sensorless control for synchronous reluctance motors (SynRMs) without signal injection and an inductance measurement for position estimation are proposed. In the case of SynRMs, accuracy of inductances is the most important factor in realizing precise position estimation because inductances are largely varied by a magnetic saturation phenomenon. Therefore, the inductance measurement method, which can measure appropriate inductances for position estimation, is important as well as a sensorless control method. The inductance measurement based on the observer is discussed, and the measurement method and the parameter adjustment method for improved stability of the closed loop are proposed. The proposed method can measure inductances easily and be applied for permanent magnet synchronous motors, too. Finally, the proposed sensorless control method is verified experimentally. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(4): 70– 80, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/ eej.20274     

Sensorless vector controlled converter for variable speed wind generation system using an induction generator

This paper proposed two types of speed sensorless converters that can control rotational speed and electric power. One is based on a slip frequency control system. The other is based on a vector control system. The rotational speed of the wind turbine is estimated with the phase voltage and phase current of the induction generator by the adaptive rotor flux observer. The estimated wind turbine rotational speed ω_r^est is used as the feedback of the speed control loop in the converter control system. Also, the estimated rotor flux ?_2d^est is used for the vector control. The simulation results confirm that both of them perform satisfactorily under the speed sensorless operation. The method based on the vector control system generates more electrical energy than does the method based on the slip frequency control system. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 159(4): 62–75, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20323     

A new initial‐rotor‐position estimation method for SPM synchronous motors using spatially rotating high‐frequency voltage: A dynamic simulator approach taking flux saturation phenomena into account

First, this paper proposes a new dynamic mathematical model of surface‐mounted permanent magnet synchronous motors (SPMSMs) with flux saturation phenomena, in a stationary reference frame. Second, based on the dynamic model, this paper establishes new dynamic simulators taking flux saturation phenomena into account, which act as very powerful tools for developing initial‐rotor‐position estimation methods for SPMSMs. Third, this paper proposes a new initial‐rotor‐position estimation method for SPMSMs. The proposed method is so simple that it inputs a spatially rotating high‐frequency voltage to SPMSMs, measures current output, and can estimate directly rotor position of N‐pole through norm evaluation of the current. The method exploits flux saturation phenomena inherent to SPMSMs and is insensitive to all motor parameters. According to experiments, the maximum estimation error is about ±0.035 rad (±2^○) in terms of mechanical angle, which is comparable to sensor mounting error and is sufficiently small for initial drive of SPMSMs. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 160(3): 63–73, 2007; Published online in Wiley InterScience ( www.interscience. wiley.com ). DOI 10.1002/eej.20241     

Fault‐tolerant control for wireless networked control systems with an integrated scheduler

This paper addresses a study of fault‐tolerant control (FTC) for wireless networked control systems (WNCSs) in industrial automatic processes. The WNCSs is composed of many subsystems, which operate with different sampling cycles. In order to meet the real‐time requirements and ensure a deterministic data transmission, the time division multiple access (TDMA) mechanism is adopted in WNCSs. The data in WNCSs are transmitted following a TDMA‐based scheduler. According to the periodicity, WNCSs integrated with the scheduler is first formulated as discrete linear time periodic systems (LTPSs). Afterwards, a fault estimation method for LTPSs is developed under a H_∞ performance specification with a regional pole constraint. With the achieved state observer and fault estimator, an FTC strategy for LTPSs is explored. Finally, the proposed methods are verified on a physical experimental WiNC platform. Copyright © 2016 John Wiley & Sons, Ltd.     

A current sensorless MPPT control method for a stand‐alone‐type PV generation system

In this paper, a current sensorless MPPT control method for a stand‐alone‐type PV generation system is proposed. This control method offers advantages of the simplified hardware configuration and low cost by using only one sensor to measure the PV output voltage. When used as a stand‐alone‐type with a battery load, the experimental results show that the estimated values of PV output current are accurate, and the use of the proposed MPPT control increases the PV generated energy by 16.3% compared to the conventional system. Furthermore, the authors clarified that the proposed method has an extremely high UUF (useful utilization factor) of 98.7%. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(2): 65– 71, 2006; Published online in Wiley InterScience ( www.interscience. wiley.com ). DOI 10.1002/eej.20424     

A novel magnet polarity identification method for initial position estimation for sensorless IPMSM drive

This paper proposes a novel magnet polarity identification method for initial position estimation during startup for interior permanent magnet synchronous machine (IPMSM) drives. The rotor's initial position estimation is based on magnetic saliency and employs high‐frequency (HF) components of the voltage and current that are excited by the multi space‐vector pulse‐width modulation (MSVPWM) pattern. However, there is a common trouble in the estimation methods based on the magnetic saliency: it is necessary to identify the magnet polarity in order to distinguish the north and south poles since the estimated position angle is a periodic function with π radians. In this paper, a novel inductance estimation method is presented and the magnet polarity is uniquely identified by the relationship between the estimated inductance and the magnetic saturation effect. Experimental results confirm the advantages of the proposed method: it is reliable, accurate, and convenient, and can be done in real time. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

基于MPC的爆胎车辆轨迹控制研究

针对爆胎车辆偏航问题,提出基于模型预测控制(model predictive control,MPC)的前轮转向控制器来对汽车偏航进行矫正,保证车辆在安全路径上行驶.基于MPC,选取简化的双轨道车辆模型,用微分方程描述车辆运动状态,线性离散化,推导预测方程,考虑车辆稳定性因素,将其添加为约束条件,转化为标准二次型计算最...     

Novel voltage limiter for fast torque response of IPMSM in voltage saturation region

A new voltage limiter for fast torque response of IPMSM in the voltage saturation region is proposed, which we name the “maximum torque response voltage limiter.” In transient condition, the fastest response is vital while voltage saturation occurs. Thus, the problem is to divide the limited voltage into d‐ and q‐axis voltages so as to generate the fastest torque response. The nonlinear relation between the torque and the d‐q axis currents of the IPMSM makes the problem complicated. In our proposed method, both voltage equations and a torque equation of the IPMSM are considered and, based on the Lagrange optimization technique, explicit expressions for the d‐ and q‐axis voltages are derived. Compared with conventional voltage limiters such as the constant phase angle method, the constant back emf method, and the constant d‐axis voltage method, the proposed limiter yields faster torque response in the voltage saturation region, which is confirmed by computer simulation and experimental results. Furthermore, the proposed method uses simple software calculations, and it can be readily implemented without any modification of the hardware system. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 175(4): 57–69, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21078     

Sensorless control of synchronous reluctance motors using on‐line parameter identification method not affected by position estimation accuracy

This paper presents a novel on‐line parameter identification method for sensorless control of Synchronous Reluctance Motors (SynRMs). Although conventional sensorless control methods based on mathematical models usually need some complex measurements of motor parameters in advance, the proposed identification method does not require them and can be realized on‐line. The proposed method identifies motor parameters under sensorless control, so rotor position and velocity cannot be used to identify these parameters. However, the proposed method does not need rotor position and velocity, and identified parameters are not affected by these estimation errors. The sensorless control using identified motor parameters is realized, and the effectiveness of the proposed method is verified by experimental results. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(3): 62–69, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20258