A DC-Bus Capacitor Discharge Strategy for PMSM Drive System With Large Inertia and Small System Safe Current in EVs
TL;DR: A physical energy flow model (EFM) is proposed to explain explicitly the winding-based discharge mechanism first and it is found that the discharge time will not be qualified when the machine rotor inertia is large and the system safe current is small.
Abstract: When an emergency happens to electric vehicles, the voltage of the dc-bus capacitor, which is an important part of the permanent magnet synchronous machine (PMSM) drive system, requires to be reduced as quickly as possible. Recently, a new idea of directly using the windings to discharge the capacitor has come forth. This paper proposes a physical energy flow model (EFM) to explain explicitly the winding-based discharge mechanism first. In the EFM, the performance characteristics of the classical winding-based discharge scheme are evaluated, but it is found that the discharge time will not be qualified when the machine rotor inertia is large and the system safe current is small. In order to reject intense voltage surge, a current control algorithm is proposed to bleed the capacitor voltage. Moreover, the proposed current control method shortens the discharge period to below 3 s for the system studied. The proposed discharge algorithm is verified by the experiment that is conducted on a three-phase PMSM drive system.
Citations
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TL;DR: A delay-suppressed sliding-mode observer to observe the real-time rotor position of a permanent magnet synchronous machine (PMSM) controlled by vector control algorithms and the observer gain is calculated by the means of a Lyapunov function in this article.
Abstract: This article presents a delay-suppressed sliding-mode observer (SMO) to observe the real-time rotor position of a permanent magnet synchronous machine (PMSM) controlled by vector control algorithms. First, in order to solve the low-pass filter (LPF) delay problem existing in the traditional signum function-based SMO, a brand new hyperbolic function is initially selected as the switching function. Because a hyperbolic function with a proper boundary layer is capable of reducing the chattering phenomenon of an SMO, it is not necessary to reemploy LPFs to eliminate the adverse impacts of chattering on the position estimation accuracy. In order to ensure the reachability and stability of the hyperbolic-function-based SMO, the observer gain is calculated by the means of a Lyapunov function in this article. Second, to solve the problem of calculation delay caused by digital computation, a current precompensation scheme based on dual-sampling strategy in one switching period is proposed. After compensating the calculation delay, the accuracy of position estimation as well as the motor control performance can be improved. Finally, the proposed SMOs with and without delay compensation are verified by both simulation and experiments that are conducted on a three-phase 1.5-kW PMSM drive prototype.
199 citations
TL;DR: A review of the electrical and electronic technologies investigated in more-electric aircraft (MEA) and the system stability and reliability issues are investigated since they are directly related to the safety of passengers.
Abstract: This paper presents a review of the electrical and electronic technologies investigated in more-electric aircraft (MEA). In order to change the current situation of low power efficiency, serious pollution, and high operating cost in conventional aircraft, the concept of MEA is proposed. By converting some hydraulic, mechanical, and pneumatic power sources into electrical ones, the overall power efficiency is greatly increased, and more flexible power regulation is achieved. The main components in an MEA power system are electrical machines and power electronics devices. The design and control methods for electrical machines and various topologies and control strategies for power electronic converters have been widely researched. Besides, several studies are carried out regarding energy management strategies that intend to optimize the operation of MEA power distribution systems. Furthermore, it is necessary to investigate the system stability and reliability issues in an MEA, since they are directly related to the safety of passengers. In terms of machine technologies, power electronics techniques, energy management strategies, and the system stability and reliability, a review is carried out for the contributions in the literature to MEA.
74 citations
Cites background from "A DC-Bus Capacitor Discharge Strate..."
...Moreover, a winding-based discharge mechanism was proposed in [24] to swiftly discharge the DC-bus capacitor in a PMSM drive system to avoid electric shock after accidents....
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TL;DR: A new finite control set model predictive control (FCS-MPC) strategy that simultaneously evaluates two targeting control objectives including speed and currents in a single cost function, achieving high-performance single-closed-loop control structure is proposed.
Abstract: This article proposes a new finite control set model predictive control (FCS-MPC) strategy that simultaneously evaluates two targeting control objectives including speed and currents in a single cost function, achieving high-performance single-closed-loop control structure. Besides, aiming at the calculation delay problem of the model predictive control controllers, a novel calculation delay compensation method by predicting the current variation within the delay time is proposed. In this article, an improved machine model that is especially designed for the multiobjective FCS-MPC operation is illustrated at first. Then, a new cost function that can evaluate the tracking performance of speed and d -axis current and the steady-state performance of the q -axis current is developed. Compared with the conventional FCS-MPC approaches, extra speed controllers are not needed so that the proposed control topology becomes simpler. Then, in order to tune the weighting factors for the speed and currents in the cost function, an efficient handling strategy containing two implementation procedures, state variable normalization and balance of state sensitivity to voltage alteration, is developed. Finally, a brand-new computation delay estimation and compensation technique based on the dual sampling within a control period is proposed to reduce the current and torque ripples during the control process. Comparative simulation and experiments conducted on a three-phase 1.5-kW permanent magnet synchronous machine drive system are employed to verify the effectiveness of the proposed techniques.
62 citations
Cites background from "A DC-Bus Capacitor Discharge Strate..."
...and high efficiency and compact structure have been heavily adopted in electric vehicles, computer numerical control machines, and other servo drives [1]–[3]....
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TL;DR: An enhanced sliding-mode observer (SMO) with current measurement error compensators for the speed and position estimation in the permanent-magnet synchronous machine (PMSM) sensorless drive scheme is established and a practical PMSM sensorless field-oriented control (FOC) scheme is constructed.
Abstract: This article establishes an enhanced sliding-mode observer (SMO) with current measurement error compensators for the speed and position estimation in the permanent-magnet synchronous machine (PMSM) sensorless drive scheme. First, hyperbolic tangent switching function-based SMO with a self-adjusted shape coefficient is realized using a fuzzy logic controller (FLC) to not only eliminate the low-pass filter (LPF) and angular compensator in the conventional SMO, but also to reduce chatter caused by the constant boundary layer thickness. On the basis of Lyapunov’s second theory, reachable and stable conditions of the enhanced SMO are founded. Then, as the current controller in the PMSM sensorless drive system needs to detect phase currents using current sensors, inevitable measurement errors exist. Two major kinds of current measurement errors, namely, the offset error and the scaling error, are analyzed. Their influences on the current fluctuations and corresponding compensation strategies are given in detail. By integrating current compensators into the enhanced SMO, a practical PMSM sensorless field-oriented control (FOC) scheme is constructed. The effectiveness of the enhanced SMO and current compensators is validated separately by comparative experiments. Final results indicate satisfactory chatter reduction and current ripple suppression performance of the proposed method.
32 citations
01 Mar 2021
TL;DR: Based on the resonant phenomenon during the fault conditions, an OCF diagnosis strategy that uses midpoint voltage as diagnosis criteria is proposed for DAB converters under the advanced TPS control to identify the faulty devices quickly and avoid the system collapse as discussed by the authors.
Abstract: Efficiency and reliability are essential for isolated bidirectional dc–dc converters in electric vehicle (EV) battery charging systems. As one promising power interface between energy storage components and power bus, dual-active-bridge (DAB) dc–dc converters have gained wide applications due to the advantages of galvanic isolation, symmetric circuit structure, high power density, and easy control implementation. In this article, based on the triple-phase shift (TPS) control, a fast and effective fault diagnosis strategy is proposed for DAB converters to improve both the power conversion efficiency and reliability. First, the operation principle of DAB converters with TPS control is presented. Then, a fast and effective open-circuit fault (OCF) analysis under different operation modes of TPS control is presented. Based on the resonant phenomenon during the fault conditions, an OCF diagnosis strategy that uses midpoint voltage as diagnosis criteria is proposed for DAB converters under the advanced TPS control to identify the faulty devices quickly and avoid the system collapse. After the failure switches are located, fault-tolerant operation is adopted to maintain the power transmission ability of DAB converters and ensure safe operation. The experimental results are provided to validate the correctness and effectiveness of the OCF performance analysis, fault diagnosis, and tolerant method.
32 citations
References
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TL;DR: Critical evaluation has been conducted on the basis of several criteria: Torque ripple, stator flux ripple, switching frequency of inverter, steady-state control performance, dynamic response, machine losses, parameter sensitivity, algorithm complexity, and stator current total harmonic distortion.
Abstract: This paper presents a comprehensive evaluation of several direct torque control (DTC) strategies for permanent magnet synchronous machines (PMSMs), namely DTC, model predictive DTC, and duty ratio modulated DTC. Moreover, field-oriented control is also included in this study. The aforementioned control strategies are reviewed and their control performances are analyzed and compared. The comparison is carried out through simulation, finite-element analysis, and experimental results of a PMSM fed by a two-level voltage source inverter. With the intent to fully reveal the advantages and disadvantages of each control strategy, critical evaluation has been conducted on the basis of several criteria: Torque ripple, stator flux ripple, switching frequency of inverter, steady-state control performance, dynamic response, machine losses, parameter sensitivity, algorithm complexity, and stator current total harmonic distortion.
204 citations
"A DC-Bus Capacitor Discharge Strate..." refers methods in this paper
...When the system works normally, port 2 is connected and the system can be controlled by any PMSM drive technique, such as double closed-loop speed regulation strategy [26] and direct torque control method [27]....
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TL;DR: Both simulation and experimental results have shown that low torque ripple and reduced stator current harmonics are achieved by using the proposed PMSM torque predictive control scheme.
Abstract: The direct torque control (DTC) technique of permanent-magnet synchronous motors (PMSMs) receives increasing attention due to its advantages in eliminating the current controllers and quicker dynamic response, compared with other motor control algorithms. However, high torque and stator flux ripples remain in the system when using DTC technologies. This means large stator voltage and current harmonic contents exist in the PM motors. Since the variation of motor electromagnetic torque is related to the voltages that are applied to the motor, by analyzing the relationships between stator flux, torque, and voltages, a PMSM torque predictive control scheme is proposed in this paper. In each digital signal processor cycle, the optimized voltage is utilized to reduce torque ripple, and the voltage vector angle is determined by the output of torque and flux hysteresis controllers. The proposed scheme is simulated and experimentally verified. Both simulation and experimental results have shown that low torque ripple and reduced stator current harmonics are achieved by using the proposed scheme.
201 citations
TL;DR: Simulation and experimental results are presented to validate the proposed constrained state feedback speed control algorithm in comparison to nonconstrained state feedback control and cascade control structure, respectively.
Abstract: This paper presents constrained state feedback speed control of a permanent-magnet synchronous motor (PMSM). Based on classical control theory, nonlinear state-space model of PMSM is developed. A simple linearization procedure is employed to design a linear state feedback controller (SFC). Digital redesign of a SFC is carried out to achieve discrete form suitable for implementation in a DSP. Model predictive approach is used to a posteriori constraint introduction into control system. It overcomes limitations of motion control system with nonconstrained SFC resulting in low dynamic properties. The novel concept utilizes machine voltage equation model to calculate the boundary values of control signals which provide permissible values of the future state variables. Secondary control objectives such as zero $d$ -axis current are included. Simulation and experimental results are presented to validate the proposed constrained state feedback control algorithm in comparison to nonconstrained state feedback control and cascade control structure, respectively.
165 citations
TL;DR: This paper analyzes the effects of the rotor position error in the performance of field-oriented-controlled permanent-magnet synchronous machine (PMSM) drives intended for electric vehicle (EV) traction applications and concludes that the torque ripple generated along the characteristic trajectories in the different operating regions of the PMSM is affected.
Abstract: This paper analyzes the effects of the rotor position error in the performance of field-oriented-controlled permanent-magnet synchronous machine (PMSM) drives intended for electric vehicle (EV) traction applications. A special focus is given to the torque ripple generated along the characteristic trajectories in the different operating regions of the PMSM. An extended and generalized model of the torque ripple produced by the PMSM as a function of the rotor position error is analytically deduced. An infinite-speed interior-(I)PMSM drive and a finite-speed surface-mounted (SM)-PMSM drive are considered for the simulations carried out in MATLAB-SimPowerSystems. The experimental results have been validated with a TM4 EV drive controlling an 80-kW SM-PMSM. The torque ripple has been evaluated for both motoring and regenerative braking operation modes under maximum torque conditions going from 100 N · m at 1000 r/min up to 55 N · m at 9000 r/min. The obtained simulation and experimental results demonstrate the good accuracy of the proposed model for evaluating the torque ripple produced in PMSMs due to the error from the rotor position sensor.
163 citations
TL;DR: This paper presents a PMSM control method based on an explicit MPC with a novel linearization and constraints handling method, allowing natural field weakening.
Abstract: Permanent-magnet synchronous machine (PMSM) drives have become popular for motion control applications due to their performance and high torque-to-weight ratio. The complex task of PMSM control in high-performance applications is currently usually resolved with classical vector control. Modern control techniques such as model predictive control (MPC) can provide significant benefits over field-oriented control, especially with straightforward controller tuning and constraints handling. Unfortunately, these new algorithms usually suffer from problems with their computational complexity. In this paper, we present a PMSM control method based on an explicit MPC with a novel linearization and constraints handling method, allowing natural field weakening. The algorithm was designed with respect to computationally feasible implementation in the control hardware. The proposed control algorithm has been proved and successfully verified in both simulation and implementation on a real motor.
122 citations
"A DC-Bus Capacitor Discharge Strate..." refers methods in this paper
...In accordance with the simulation results, the q-axis current (about 14 A) is generated automatically at the time when the discharge is requested, while it starts to decline from 2.5 s and reaches below -5 A at 6.0 s. Additionally, f2 and f3 can be calculated according to the EFM, and Fig....
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...In the first place, this paper proposes an EFM model, which is a combination of energetics and electromagnetics, and it is utilized to illustrate the mechanism of the traditional windingbased discharge algorithms and performance characteristics in the process of bleeding....
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...Section II describes an EFM and presents the mechanism of the windingbased discharge strategies....
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...On the basis of EFM, the key technique proposed in this paper to avoid the voltage surge can be described as letting f2 f3 over each period of t....
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...Thus, before analyzing the winding-based discharge schemes, the so-called EFM is established....
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