This paper concerns the realization of a sensorless permanent magnet (PM) synchronous motor drive. Position and angular speed of the rotor are obtained through an extended Kalman filter. The estimation algorithm does not require either the knowledge of the mechanical parameters or the initial rotor position, overcoming two of the main drawbacks of other estimation techniques. The drive also incorporates a digital d-q current control, which can be easily tuned with locked rotor. The experimental setup includes a PM synchronous motor, a pulsewidth modulation voltage-source inverter, and floating-point digital-signal-processor-based control system.

Sensorless full-digital PMSM drive with EKF estimation of speed and rotor position

In this paper, a generalized discontinuous pulsewidth modulation (GDPWM) method with superior high modulation operating range performance characteristics is developed. An algorithm which employs the conventional space-vector PWM method in the low modulation range, and the GDPWM method in the high modulation range, is established. As a result, the current waveform quality, switching losses, voltage linearity range, and the overmodulation region performance of a PWM voltage-source inverter (PWM-VSI) drive are optimized online, as opposed to conventional modulators with fixed characteristics. Due to its compactness, simplicity and superior performance, the algorithm is suitable for most high-performance PWM-VSI drive applications. This paper provides detailed performance analysis of the method and compares it to the other methods. The experimental results verify the superiority of this algorithm to the conventional PWM methods.

/pdf/a-high-performance-generalized-discontinuous-pwm-algorithm-3lrbvzvveu.pdf

A high-performance generalized discontinuous PWM algorithm

Electric traction is one of the most promising technologies that can lead to significant improvements in vehicle performance, energy utilization efficiency, and polluting emissions. Among several technologies, hybrid electric vehicle (HEV) traction is the most promising technology that has the advantages of high performance, high fuel efficiency, low emissions, and long operating range. Moreover, the technologies of all the component hardware are technically and markedly available. At present, almost all the major automotive manufacturers are developing hybrid electric vehicles, and some of them have marketed their productions, such as Toyota and Honda. This paper reviews the present technologies of HEVs in the range of drivetrain configuration, electric motor drives, and energy storages

Hybrid Electric Vehicles: Architecture and Motor Drives

Electromagnetic interference (EMI) noise is defined as an unwanted electrical signal that produces undesirable effects in a control system, such as communication errors, degraded equipment performance and malfunction or nonoperation. This article provides a common understanding of the EMI issues and provides simple pre-installation and post-installation guidelines useful for all interested parries involved in the industry application of adjustable speed PWM invertor-fed AC motor drives.

EMI emissions of modern PWM AC drives

In this paper, the overmodulation region voltage-gain characteristics and waveform quality of carrier-based pulsewidth-modulated (PWM) methods are investigated. Through detailed analytical study, voltage-gain characteristics are extracted independent of carrier frequency. The influence of blanking time and minimum pulsewidth (MPW) control on the inverter gain characteristics are studied and shown to be significant. A comparative evaluation of the modulator characteristics reveals the advantageous high-modulation-range characteristics of discontinuous PWM methods and, in particular, the superior overmodulation performance of a discontinuous PWM method. The modulation methods under consideration are tested on a PWM voltage-source inverter (VSI)-fed induction motor drive in the laboratory, and the theoretical results are verified by experiments. Also, a gain linearization technique is presented and experimentally verified. The results of this study are useful in the design, performance prediction and development of high-performance overmodulation strategies for PWM-VSI drives.

/pdf/carrier-based-pwm-vsi-overmodulation-strategies-analysis-21hivzp1ac.pdf

Carrier-based PWM-VSI overmodulation strategies: analysis, comparison, and design

This paper investigates overvoltage transients on AC induction motors when connected through a cable of arbitrary length to a variable frequency drive (VFD) consisting of a pulsewidth modulation (PWM) inverter with insulated gate bipolar transistor (IGBT) power devices. Factors contributing to a motor overvoltage transient equal to a theoretical twice DC bus voltage are first described using existing transmission line analysis. A critical cable distance I/sub c/ is defined where this 2-pu overvoltage occurs. However, literature is lacking on flow motor voltage transients >2-pu bus voltage and up to 3-4 pu are generated. This phenomenon is observed on all PWM inverters with output cable lengths greater than l/sub c/ distance. Contributing factors to the >2-pu overvoltage phenomenon are investigated by exploring the complex interaction between drive modulation techniques, carrier frequency selected, cable natural frequency of oscillation, cable high-frequency damping losses, and, to a lesser extent, inverter output rise time. Theoretical calculations of cable frequency and damping are correlated with simulation and experimental results. Novel modifications to the PWM modulator, as well as external hardware apparatus, are proposed solutions to the >2-pu overvoltage problem; both are simulated and experimentally confirmed.

https://www.bhelpswr.co.in/SAS/T%201/Electrical/Arvind%20gupta%20Papers/VFD_paper_13.pdf

Interaction of drive modulation and cable parameters on AC motor transients

Three simple methods of adapting for rotor time constant changes of an indirect field-oriented induction machine are proposed These methods utilize voltages as field-oriented reference models in the basic model reference adaptive control (MRAC) structure Each of these methods offers some implementation or performance advantage over previously proposed MRAC methods and other adaption techniques The proposed methods are analyzed along with other previously proposed MRAC methods, and the advantages and limitations of each are discussed Experimental results are presented for the proposed methods with the most advantages >

A simple on-line adaptation for indirect field orientation of an induction machine

Reflected wave transient voltages that are impressed on drive output cables and low voltage AC induction motors are simulated with an excitation source of steep fronted d/spl nu//dt pulse waveforms from a pulse width modulated (PWM) voltage source inverter. Motivation for system simulation arises from a need to correlate reflected wave peak voltage and risetime with the dielectric insulation capability of both motor and cable. Simulations based on an accurate system model also allow investigation into the effects of changing wire gauge, motor HP, cable distance or addition of drive output filters. System parameters of the inverter, cable and motor model are investigated in detail. Special emphasis is given to the importance of modeling cable skin and proximity effects. Simulation, measured lab and field results are compared. The main objective of the paper is to propose a reflected wave building block model that uses existing software on the market, is simple, computationally fast, easily configurable, reasonably accurate and allows investigation with wide variation of system parameters.

Reflected wave modeling techniques for PWM AC motor drives

Overvoltage transients occur on AC induction motors when connected through a power cable of sufficient length to a variable speed AC drive consisting of a PWM inverter and IGBT power devices. Factors contributing to a motor overvoltage transient equal to twice the theoretical DC bus voltage are described using classical transmission line analysis. A critical cable distance (I/sub c/) is defined where twice the DC bus overvoltage occurs. However, literature is lacking on how motor transients greater than twice the DC bus voltage are generated. This phenomenon is observed on all PWM inverters with output cable lengths greater than the I/sub c/ distance. Theoretical calculations of cable frequency and damping are correlated with simulation and experimental results. Finally, the paper presents an external hardware apparatus (the Terminator), based on a cable's characteristic impedance, that clamps the motor's terminal voltage to levels far below twice the DC bus voltage. All calculations and proposed solutions are verified or demonstrated with experimental results.

Cable characteristics and their influence on motor over-voltages

The impact of common-mode voltage (CMV) generated by pulsewidth modulation (PWM) ac drives on motor bearings is well known. Several algorithms for CMV reduction have been proposed in the literature. While a few algorithms assume ideal switching and fall apart when nonidealities like inverter dead time are considered, some others are effective only in a limited operating range of the drive. In this paper, a previously proposed algorithm is modified for practical implementation to include compensation for dead-time and reflected-wave motor overvoltage stress while still producing output voltage waveforms with reduced common-mode content. Experimental results are provided to show the reduction in CMV over the entire operating range, with other performance attributes such as reflected-wave motor overvoltage that are identical to conventional space-vector PWM. The advantages of applying the algorithm to a fully regenerative ac drive are also demonstrated.

David Leggate

Papers

Interaction of drive modulation and cable parameters on AC motor transients

A simple on-line adaptation for indirect field orientation of an induction machine

Reflected wave modeling techniques for PWM AC motor drives

Cable characteristics and their influence on motor over-voltages

Common-Mode Voltage Reduction PWM Algorithm for AC Drives