An Integral Battery Charger with Power Factor Correction for Electric Scooter

This paper presents an integral battery charger for an electric scooter with high voltage batteries and interior-permanent-magnet motor traction drive. The battery charger is derived from the power hardware of the scooter, with the ac motor drive that operates as three-phase boost rectifier with power factor correction capability. The control of the charger is also integrated into the scooter control firmware that is implemented on a fixed-point DSP controller. Current-controlled or voltage-controlled charge modes are actuated according to the requirements of the battery management system, that is embedded into the battery pack. With respect to previous integrated chargers, the ac current is absorbed at unitary power factor with no harmonic distortion. Moreover, no additional filtering is needed since the pulsewidth modulation ripple is minimized by means of phase interleaving. The feasibility of the integral charger with different ac motors (induction motor, surface-mounted phase modulation motor) is also discussed, by means of a general model purposely developed for three-phase ac machines. The effectiveness of the proposed battery charger is experimentally demonstrated on a prototype electric scooter, equipped with two Li-ion battery packs rated 260 V, 20 A

Handling input voltage frequency variations in power factor correctors with precalculated duty cycles

Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. F. Lopez-Colino, A. Sanchez, G. Alvarez, A. de Castro, and J. Garrido. "Handling input voltage frequency variations in power factor correctors with precalculated duty cycles", in IEEE 15th Workshop on Control and Modeling for Power Electronics (COMPEL), 2014, pp. 1-5The use of precalculated duty cycles for power factor correction leads to a significant simplification of the design and a reduction of the final cost. There are previous proposals for handling non-nominal conditions such as input voltage or load variations. However, there are no proposals for handling input frequency variations, which have an important impact in the power factor. This paper measures this impact and includes a simple loop to handle the variations of the input frequency. The results show that the introduction of this loop keeps the power factor values around those obtained in nominal conditions.This work has been supported by the Spanish Ministerio de Ciencia e Innovación under project TEC2013-43017-R

Measurements, Models, Systems and Design

531 s.

A Control Scheme for an AC-DC Single-Stage Buck-Boost PFC Converter with Improved Output Ripple Reduction

AC-DC power factor correction (PFC) single-stage converters are attractive because of their cost and their simplicity. In these converters, both PFC and power conversion are done at the same time using a single converter that regulates the output. Since they have only a single controller, these converters operate with an intermediate transformer primary-side DC bus voltage that is unregulated and is dependent on the converters’ operating conditions and component values. This means that the DC bus voltage can vary significantly as line and load conditions are changed. Such a variable DC bus voltage makes it difficult to optimally design the converter transformer as well as the DC bus capacitor. One previously proposed single-stage AC-DC converter, the Single-Stage Buck-Boost Direct Energy Transfer (SSBBDET) converter has a clamping mechanism that can clamp the DC bus voltage to a pre-set limit. The clamping mechanism, however, superimposes a low frequency 120 Hz AC component on the output DC voltage so that some means must be taken to reduce this component. These means, however, make the converter transient slow and sluggish. The main objective of this thesis is to minimize the 120 Hz output ripple component and to improve the dynamic response of the SSBBDET converter by using a new control scheme. In the thesis, the operation of the SSBBDET converter is reviewed and the proposed control method is introduced and explained in detail. Key design considerations for the design of the converter controller are discussed and the converter’s ability to operate with fixed DC bus voltage, low output ripple and fast dynamic response is confirmed with experimental results obtained from a prototype converter

Hardware implementation of boost power factor correction converter.

Nowadays, there has been an increasing demand of unity power factor in electrical power sector. Due to the nonlinear nature of load equipment, switching devices, source voltage and current are out of phase with each other. Many power converters topologies are used for the power factor correction. The boost converter with controller is most common for power factor correction circuits. The controller objective is to maintain the output voltage regulation and input current tracking with source voltage. The voltage ripple present due to the ac component of the current tracking objective, hence instead of ignoring that ripple, it is used in controller designing. The mathematical modeling of system depends on ac and dc dynamics of the circuit. The Lypunov stability analysis used for designing the controller of boost converter. In this work, experimental set-up for boost power factor correction converter was made with power pole board and NI compact RIO. The controller algorithm executed in LabVIEW FPGA module and results were verified. This novel controller ensures the convergence of the error signal by stability analysis

Relationship of servant leadership with employee in-role and extra-role performance in GLC’s of Malaysia

This research aims to study the relationship of servant leadership with employee performance of in-role and extra role performance. Servant leadership, and its relationship with employee OCB and task performance are discussed to start with. Though some literature is available on links of servant leadership with employee task performance or Organizational Citizenship Behaviors, but how these two behaviors interact is not explained much. This paper explains that servant leadership has positive relationship with OCB. Though, other leadership approaches are different from servant leadership as its focus is on personal integrity and lasting relationships with employees