Pulse Amplitude Modulation Control Research Articles

Modified preactuation tracking control for LPV systems with application to boost converters

Boost converters are usually employed as constant or discrete variable voltage sources. They are expected as a continuously variable voltage source for electric drives (based on pulse-amplitude modulation control), or for reduction of the size of energy buffer components for mass motor drives. When changing the output voltage of boost converters according to the duty ratio, the nonlinear and nonminimum phase characteristics of boost converters cause undershoots. This study was devoted to extending the technique known as preactuated multirate feedforward (PMF), which can effectively compensate for the effects caused by nonminimum phase characteristics in boost converters. PMF was originally considered for linear time-invariant systems. In this study, the technique was extended to linear parameter-varying systems by the interpolation method. Simulation and experimental results verified the effectiveness of the proposed approach.

One-Cycle Controlled Bridgeless SEPIC with Coupled Inductors for PAM Control-Based BLDC Drive

This paper presents a novel approach for the speed control of BLDC motor for residential air conditioning application, using pulse amplitude modulation (PAM) control of voltage source inverter (VSI). PAM control of VSI is accomplished by using a bridgeless SEPIC converter embedded with coupled inductors at the front end and adopting one-cycle control (OCC) technique in the inner voltage control loop. The DC reference voltage required for inner voltage control loop is obtained using a PI controller in the outer speed control loop and speed feedback signal. The PAM control (DC supply voltage control) of VSI reduces switching losses by allowing the operation of VSI at fundamental frequency. Bridgeless SEPIC with coupled inductors is designed to enable PAM control for VSI and is operated in discontinuous conduction mode (DCM) for the complete range of DC link voltage. DCM operation simplifies power factor correction control scheme to a simple voltage follower approach, since it has inherent input current shaping feature. The introduction of coupled inductors in the bridgeless SEPIC converter lowers the overall count of components, allows better integration and lowers the requirement of inductance, compared to conventional bridgeless SEPIC. OCC which is a nonlinear control technique, used in the voltage control loop, enhances the performance with improved startup and transient state response. It also improves the quality of supply current drawn by reducing the distortion compared to PI control technique. The proposed BLDC motor drive is modelled and simulated using MATLAB/Simulink. The performance of proposed system is evaluated for a wide range of speed control. The experimental prototype for bridgeless SEPIC with coupled inductors is implemented. The inherent power factor correction for supply voltage variations is validated using the results. The bridgeless operation of the converter with coupled inductor configuration is also described with experimental waveforms at rated supply voltage of 220 V.

Influence of Phase Magnetic Couplings on Phase Current Characteristics of Multiphase BLDC Machines With Overlapping Phase Windings

Multiphase brushless dc (BLDC) machines are implemented in electric and hybrid electric vehicle applications due to their high torque/power density, good fault tolerance capability, and low torque ripple. Moreover, the per-phase converter rating can be reduced by increasing the phase number. However, the number of magnetic couplings between phases increases with the phase number, and these magnetic couplings can have an important influence on the machine performance. Therefore, they need to be considered in simulation models and their effect should be considered in control algorithms. Accordingly, the objective of this paper is to analyze the effect of magnetic phase couplings on the performance of multiphase BLDC machines with an overlapping phase winding configuration. First, a detailed electric machine model, in which the machine parameters that are determined by 2-D finite-element method analysis are implemented, is developed. Using this model, the influence of mutual inductances on phase current characteristics with pulse amplitude modulation (PAM) and pulsewidth modulation (PWM) controls is investigated. In addition, a novel PAM-based control strategy, in which the effect of phase mutual inductances is considered, is proposed and analyzed. After demonstrating the influence of mutual inductances on phase current characteristics, the dependence of mutual inductances on the winding configuration is studied. Finally, experimental results with the PAM control and the new PAM-based control are used to validate the simulation results.

A Novel Drive Method for High-Speed Brushless DC Motor Operating in a Wide Range

In this paper, a novel drive method, which is different from the traditional motor drive techniques, for high-speed brushless DC (BLDC) motor is proposed and verified by a series of experiments. It is well known that the BLDC motor can be driven by either pulse-width modulation (PWM) techniques with a constant dc-link voltage or pulse-amplitude modulation (PAM) techniques with an adjustable dc-link voltage. However, to our best knowledge, there is rare study providing a proper drive method for a high-speed BLDC motor with a large power over a wide speed range. Therefore, the detailed theoretical analysis comparison of the PWM control and the PAM control for high-speed BLDC motor is first given. Then, a conclusion that the PAM control is superior to the PWM control at high speed is obtained because of decreasing the commutation delay and high-frequency harmonic wave. Meanwhile, a new high-speed BLDC motor drive method based on the hybrid approach combining PWM and PAM is proposed. Finally, the feasibility and effectiveness of the performance analysis comparison and the new drive method are verified by several experiments.

A? Fuzzy Controller Based High Efficient Pulse Amplitude Modulation Control for a Permanent Magnet Synchronous Motor

A pulse amplitude modulation (PAM) control can adjust the DC-link voltage of a motor drive. A bi-directional buck-boost DC-DC converter is required at the primary side of PWM-VSI to implement PAM control. This paper is proposed PAM control technique for a permanent magnet synchronous motor (PMSM) based on fuzzy control system. The PAM coefficient (K_PAM) is a constant value for a conventional PAM control system. It requires online adjustment to improve overall performance of a PAM control system. The proposed fuzzy controller based PAM control regulates the K_PAM according to online commanded load voltage. This paper deals with different operation modes of a bi-directional buck-boost DC-DC cascade converter, motoring (accelerate and steady state) and braking operations of a PMSM at different load conditions and speeds. The total harmonic distortion (THD) and system efficiency are also shown in this paper. Effectiveness of the proposed method is confirmed by simulation results.

Optimal PAM Control for a Buck Boost DC-DC Converter with a Wide-Speed-Range of Operation for a PMSM

A pulse width modulation-voltage source inverter (PWM-VSI) is used for variable speed permanent magnet synchronous motor (PMSM) drives. The PWM-VSI fed PMSM has two major disadvantages. Firstly, the PWM-VSI DC-link voltage limits the magnitude of the PMSM terminal voltage. As a result, the motor speed is restricted. Secondly, in a low speed range, the PWM-VSI modulation index declines. This is caused by a high DC-link voltage and a low terminal voltage ratio. As a result, the distortion of the voltage command and the stator current are increased. This paper proposes an optimal pulse amplitude modulation (PAM) control which can adjust the inverter DC-link voltage by using a buck-boost DC-DC converter. At a low speed range, the proposed system can reduce the distortion of the voltage command, which improves the stator current waveform. Also, the allowable speed range is extended. In order to verify the proposed method, experimental results are provided to confirm the simulation results.

A PAM control method for a matrix converter based on a virtual AC/DC/AC conversion method

AbstractIn this paper, a novel control method for a matrix converter is proposed. The proposed method is a PAM (Pulse Amplitude Modulation) control method based on a virtual AC/DC/AC conversion method. Output voltage amplitude is controlled by controlling a virtual DC link voltage with a virtual rectifier. Output frequency is controlled by a virtual inverter.First, the proposed method is explained. Next, the validity of the proposed method is confirmed through simulation and experiment using a 750‐W prototype matrix converter. Moreover, various characteristics of the proposed method and conventional virtual AC/DC/AC method are compared through experiment. As a result of the experiment, it has been understood that total harmonic distortion of output current and common‐mode voltage can be reduced compared with the case of using a conventional virtual AC/DC/AC conversion method. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(4): 88–96, 2009; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/eej.20601

A PAM Control Method for Matrix Converter Based on Virtual AC/DC/AC Conversion Method

In this paper, a novel control method for a matrix converter is proposed. The proposed method is a PAM (Pulse Amplitude Modulation) control method based on a virtual AC/DC/AC conversion method. Output voltage amplitude is controlled by controlling a virtual DC link voltage with a virtual rectifier. Output frequency is controlled by a virtual inverter.Firstly, the proposed method is explained. Next, the validity of the proposed method is confirmed thorough simulation and experiment using a 750W prototype matrix converter. Moreover, various characteristics of the proposed method and conventional virtual AC/DC/AC method are compared through experiment. As a result of experiment, it has been understood that total harmonic distortion of output current and common-mode voltage can be reduced compared with the case of using a conventional virtual AC/DC/AC conversion method.

Analysis of the commutation processes for PAM inverter having one LC-commutation circuit only

In this paper, the analysis of the commutation processes and design of the forced commutation circuit is presented for the PAM inverter with having one LC-commutation circuit only and new pulse amplitude modulation control technique are described for this inverter, which eliminate the stator current harmonics of an order lower than 17th. Based on this principle resulting in a higher stability of the machine operation in the dynamic regime.