Fan Applications Research Articles

Design Constraints of Small Single-Phase Permanent Magnet Brushless DC Drives for Fan Applications

Permanent magnet brushless dc (BLDC) machines are widely used due to various advantages such as high efficiency and high torque density, and therefore compactness as well as long expected lifetime. All of these benefits are of major interest when designing a drive for a small fan application of a few watts. This paper presents the design investigations of a small single-phase BLDC motor for such an application. Notably, it discusses different constraints which arise during the design process and which may be of special relevance due to the particular given power level and application.

Sensorless Control of Low-Cost Single-Phase Hybrid Switched Reluctance Motor Drive

This paper presents a sensorless-controlled, low-cost, low-power, and variable-speed drive system suitable for fan and pump applications. The main advantages of this drive system are the low system cost, simple converter structure, and simple but robust sensorless control technique. The drive motor is a special hybrid switched reluctance motor. The proposed sensorless control method beneficially utilizes the stator side PM field and its performance is motor parameter independent. The unique low-cost drive system solution, simple and robust sensorless control features of this drive system, is demonstrated in detail in this paper. Important design details for practical implementation of the sensorless control algorithm are included. The complete drive system performance is validated using a prototype drive system.

A Performance Prediction Model for Low-Speed Centrifugal Fans

A generalized model for mapping the trend of the performance characteristics of a double-discharge centrifugal fan is developed based on the work by Casey and Robinson (C&R), which formulated compressor performance maps for tip-speed Mach numbers ranging from 0.4 to 2 using test data obtained from turbochargers with vaneless diffusers. The current paper focuses on low-speed applications for Mach number below 0.4. The C&R model uses four nondimensional parameters at the design condition including the flow coefficient, the work input coefficient, the tip-speed Mach number, and the polytropic efficiency, in developing a prediction model that requires limited geometrical knowledge of the centrifugal turbomachine. For the low-speed fan case, the C&R formulas are further extended to a low-speed, incompressible analysis. The effort described in this paper begins by comparing generalized results using efficiency data obtained from a series of fan measurements to that using the C&R model. For the efficiency map, the C&R model is found to heavily depend on the ratio of the flow coefficient at peak efficiency to that at the choke flow condition. Since choke flow is generally not applicable in the low-speed centrifugal fan operational environment, an alternate, but accurate estimation method based on fan free delivery derived from the fan test data is presented. Using this new estimation procedure, the modified C&R model predicts reasonably well using the double-discharge centrifugal fan data for high-flow coefficients, but fails to correlate with the data for low-flow coefficients. To address this undesirable characteristic, additional modifications to the C&R model are also presented for the fan application at low flow conditions. A Reynolds number correction is implemented in the work input prediction of the C&R model to account for low-speed test conditions. The new model provides reasonable prediction with the current fan data in both work input and pressure rise coefficients. Along with the developments for the efficiency and work input coefficient maps, the use of fan shut-off and free delivery conditions are also discussed for low-speed applications.

High speed machining of nickel-based alloys

The connection between rotor disc and blades in turbine applications is usually realised by complex profiled grooves. The profiled grooves are mostly manufactured by broaching processes. In compressor and fan applications, alternative cutting processes such as milling and broaching with more advanced cutting materials are already implemented. In turbine applications, where nickel-based alloys are used due to high forces and temperatures, the use of HSS-tools is still state of the art. Due to the low high temperature strength of this cutting material, cutting speeds do not exceed vc = 2-5 m/min. The use of alternative manufacturing processes for roughing therefore has a high potential. This paper presents experimental results on rough side milling of nickel-based alloys with whisker reinforced ceramics at cutting speeds up to vc = 1,500 m/min including wear behaviour and metallographic analysis. The results are compared to further alternative processes discussed to complement the broaching of profiled grooves and broaching with alternative tool grades.

Optimization of a Novel Solar Heat Pipe Heat Recovery Fan

A novel heat pipe recovery fan has been proposed in order to improve the indoor environment, which can be either a perfect supplement to the traditional desiccant technology or an alternative. Heat pipe can be applied to recycle heat and enhance solution dehumidification. This paper presents a new technological process that the heat can be derived from waste water and solar energy can be reserved to use when necessary. By applying the correlated coefficient, the performance of the system is presented in terms of dehumidification capacity and heat recovery efficiency by simulation. The effect of supplying air flow rate on the airborne pollutant transports are also illustrated based on the new fan with the indoor heat source. The results demonstrate that the best indoor rate for the present system is limited to 0.3ms–1. In addition, the the liquid to gas flow rate ratios(L/G) has a great influence on dehumidification effectiveness and heat recovery effectiveness. The conclusion can be used as reference information for the optimization of new fan design and application.

Design and Analysis of a Magnetless Double-Rotor Flux Switching Motor for Low Cost Application

This paper presents a novel magnetless double-rotor flux switching motor for low cost cooling fan application. By creatively incorporating concentrated toroidal windings into a double-rotor middle-stator structure, the proposed motor not only realizes the flux switching feature, but also shortens the end-windings to improve its operational efficiency. To achieve a better performance, the motor dimensions, especially the stator and rotor pole arcs, are optimized. Meanwhile, with the introduction of a stepped air-gap, the torque at any rotor position is boosted and problems with zero output torque at starting is successfully avoided. The final optimized motor is analyzed using finite element method, and its validity is confirmed by the simulation results.

팬구동용 저압 8/6 SRM의 설계 및 구동 특성

팬구동용 저압 8/6 SRM의 설계 및 구동 특성

Characteristics Analysis of a Novel Segmental Rotor Axial Field Switched Reluctance Motor with Single Teeth Winding

A novel 12/10 axial field switched reluctance motor (AF-SRM) is proposed for cooling fan applications in this paper. Unlike from conventional structures, the proposed motor uses the axial field instead of the radio field, the rotor is constructed from a series of discrete segments, and the stator poles are constructed from two types of stator poles: exciting and auxiliary poles. This concept improves the torque capability of a previous design by reducing the copper volume, which leads to a higher efficiency. To verify the proposed structure, the finite element method (FEM) and Matlab-Simulink are employed to get characteristics of the proposed SRM. Finally, a prototype of the proposed motor was tested for characteristic comparisons.

Design and Analysis of a Segmental Rotor Type 12/8 Switched Reluctance Motor

In this paper, a novel 12/8 segmental rotor type switched reluctance motor (SRM) is proposed for cooling fan applications. Unlike conventional structures, the rotor of the proposed structure is constructed from a series of discrete segments, and the stator is constructed from two types of stator poles: exciting and auxiliary poles. Moreover, in this structure, short flux paths are taken and no flux reversion exists in the stator. While the auxiliary poles are not wound by the windings, which only provide the flux return path. When compared with the conventional SRM, the proposed structure increases the electrical utilization of the machine and decreases the core losses, which may lead to a higher efficiency. To verify the proposed structure, the finite element method (FEM) and Matlab-Simulink are employed to get the static and dynamic characteristics of the proposed SRM. Finally, a prototype of the proposed motor was tested for characteristic comparisons.

Experimental Identification and Reduction of Acoustic Noise in Small Brushed DC Motors

The smart actuators and components designed for automotive applications have to satisfy the standards and specifications of costumers, who are becoming more and more demanding, concerning the acoustic-noise emissions. Starting from an accurate experimental test campaign, which identifies the cogging torque as the main cause of the acoustic-noise source in the considered small brushed dc motors for radiator cooling fan applications, the authors discuss and propose some alternative redesign solutions of the electrical machine that are able to mitigate the problem. The feasibilities of the proposed solutions are compatible with the competitive automotive component market and the actual automatic production lines. Several prototypes have been manufactured and tested in the same semi-anechoic chamber similar to the original motor set in order to comparatively evaluate the goodness of the potential electrical machine redesigns in terms of acoustic-noise reduction. The reported acoustic-noise measurements prove that, for the considered application, the acoustic-noise emissions can be reduced.

Sensorless and energy-efficient PMSM drive for fan application

Abstract The paper presents the problem of sensorless control of a permanent magnets synchronous motor (PMSM) without a damping cage for fan applications. Frequency control was used according to the principle of v/f = const. In order to reduce the power consumption of the drive system, the optimal voltage to the motor frequency characteristics was tested in the laboratory. The experimental studies was performed on a laboratory set of a drive consisting of two coupled PMSM machines, where one machine was supplied by a transistor inverter and the other was a passive load. A new criterion based on minimizing the module of stator current vector was proposed and an optimization algorithm in steady states was tested. The results of laboratory tests confirmed the validity of the applied solution for the fan drive.

Digital Implementation of PWM Techniques for Two-phase Eight-switch Inverter fed Brushless DC Motor Drives

This paper reports an investigation of pulse width modulation (PWM) techniques for two-phase brushless DC (BLDC) motors fed by a two-phase eight-switch inverter in a fan application. The three-phase BLDC motor is widely applied in industry; however, a lower-cost two-phase BLDC motor and drive circuit has been greatly in demand in recent years. In this paper, we introduce a mathematical model of the two-phase BLDC motor with sinusoidal back electromotive forces (EMFs) based on traditional three-phase BLDC motors. To simplify the drive algorithm and speed up its application, we analyze the principle of block commutation for a two-phase BLDC motor drive in the 180-electrical-degree conduction mode, and we further propose five PWM schemes to improve the commutation performance of the two-phase BLDC drive. The effectiveness of the proposed PWM methods is verified through experiments.

Performance Analysis and the Cost Effective Position Sensorless Control of Axial Flux PM Brushless DC Motor

The aims of this paper are the simple comparison of the axial flux (AF) structures versus the radial flux (RF) structures for brushless permanent-magnet (PM) synchronous motors and proposing a cost effective position sensorless control strategy for AFPM Brushless DC Motor. The comparison is developed for different motor dimensions. Moreover, a cost effective and position sensorless control strategy proposed for AFPM brushless DC (BLDC) motor drive using single current sensor. It is based on the generation of quasi-square current waveforms, using only one current controller for the three phases. Unlike the conventional methods, the proposed method presents advantages such as very simple control scheme, without needing to triangular carrier modulation, and balanced phase currents. The proposed position sensorless technique is based on the detection of zero crossing points of three voltage functions that are derived from the difference between the lines’ voltage measured at the terminals of the motor. This control algorithm is particularly suitable for cost sensitive product such as air purifiers, air blowers, cooling fan, and related home applications. The effectiveness of the proposed control system have been validated by simulation results.

Thermal Analysis of Interior Permanent-Magnet Synchronous Motor by Electromagnetic Field-Thermal Linked Analysis

This paper reports an investigation of pulse width modulation (PWM) techniques for twophase brushless DC (BLDC) motors fed by a two-phase eight-switch inverter in a fan application. The three-phase BLDC motor is widely applied in industry; however, a lower-cost two-phase BLDC motor and drive circuit has been greatly in demand in recent years. In this paper, we introduce a mathematical model of the two-phase BLDC motor with sinusoidal back electromotive forces (EMFs) based on traditional three-phase BLDC motors. To simplify the drive algorithm and speed up its application, we analyze the principle of block commutation for a two-phase BLDC motor drive in the 180-electricaldegree conduction mode, and we further propose five PWM schemes to improve the commutation performance of the two-phase BLDC drive. The effectiveness of the proposed PWM methods is verified through experiments.

Thermal Analysis and Test for a High Speed PM Machine for Fan Application

For a give air flux, the higher speed the fanner is running, the smaller the fanner’s size is. It is also well known that for a given power, the higher the machine’s running speed, the smaller the machine’s size has. If the fanner is geared to a high speed machine directly, the fan set’s volume will be sharply decreased. However, the heat dissipation of the high speed machine becomes a serious problem also due to the small size and high power loss density. Therefore, how to estimate accurately the power losses and temperature rise is a key issue for the high speed machine design. In this paper, the power losses and temperature of high speed PM machine for a fanner application are thoroughly investigated. And the test results of a prototype fan set partly shown the validity of the calculation method.

Development of an Axial Gap Motor With Amorphous Metal Cores

This paper presents a novel motor design concept that utilizes amorphous cut cores in the stator and ferrite magnets in the rotor to obtain a high-efficiency motor. This motor employs a six-pole nine-slot axial gap construction and aims to provide 90% efficiency with decreased size and low cogging torque for fan motor applications. Amorphous cut cores are applied to the stator to decrease iron loss and save motor space. Skewed magnets are employed to decrease cogging torque. Three-dimensional finite element analysis was used to analyze motor performance. In order to verify the accuracy of the design, a trial motor was constructed, and a large range of experiments was conducted to measure the motor characteristics. The results of the trial motor meet the design goals.

플럭스 스위칭 전동기의 고효율 드라이브에 대한 연구

A new class of electronically commutated brushless motor, the flux-switching motor(FSM) is gradually emerging in power tools and household appliances especially fan and pump application because of green policy. This motor offers advantages of high-power density and relatively high efficiency compare with induction motor, low cost and simple motor structure compare with bldc motor. This paper presents the principle of the FSM and design of the 12/6 pole FSM drive system for fan application. Finally, test results of the prototype motor are provided to verify a validity of the fan application with TMS320F2812 DSP and inverter.

A Study on a Flux Switching Motor Drive for Fan Application

A new class of electronically commutated brushless motors, the flux-switching motor (FSM), is gradually emerging for use in power tools and household appliances especially fan and pump application thanks to green policies. This motor offers such advantages as high-power density and relatively high efficiency compare to induction motors, and low cost and simple motor structure compare to the BLDC motor. This paper presents the principle of the FSM and design of the 12/6 pole FSM drive system for fan application. Test results of the prototype motor are provided to verify the validity of the fan application with a TMS320F2812 DSP and inverter.

선행각을 이용한 팬용 플럭스 스위칭 전동기 드라이브에 대한 연구

최근에는 파워툴(power tools)과 가전 제품에 있어서 전자적인 전류(commutation)를 사용하는 새로운 형태의 브러시리스 전동기인 플럭스 스위칭 전동기(Flux switching motor)에 대한 관심이 점차적으로 증가되고 있으며, 특히 팬과 펌프 시장에 있어서는 그린 정책으로 인하여 플럭스 스위칭 전동기에 대한 관심이 급격히 증가되고 있다. 플럭스 스위칭 전동기는 유도전동기에 비해서는 높은 전력 밀도(power density)와 상대적으로 높은 효율, 그리고 브러시리스 DC 전동기에 비해서는 간단한 전동기 구조와 가격 경쟁력이라는 장점을 가지고 있다. 따라서 본 논문에서는 팬 용도로 제작된 12/6 폴을 가지는 플럭스 스위칭 전동기의 드라이브 설계와 동작원리에 대해서 나타내고, 팬 용도로 제작된 프로토타입 플럭스 스위칭 전동기의 타당성을 검증하기 위해서 TMS320F2812 DSP와 일반적인 인버터를 이용한 실험 결과를 제시한다.

Convection and radiation combined surface heat transfer coefficient in baking ovens

The combined surface heat transfer coefficient is a determining parameter of convective baking process time and efficiency, as well as the resulting food product quality. By this study, the combined surface heat transfer coefficient term was determined at the convective oven temperature range of 70–220 °C, with fan (turbo) and without fan (static oven) applications. The methods of “Lumped Capacity” and “Time–Temperature Matching” were used. Both methods utilize the time–temperature data at a fixed position of a definite material, during unsteady state heating up period inside the convective oven. The increase in oven temperature and the fan application in the oven derived higher calculated values of surface heat transfer coefficients. Good agreement was observed between both methods and the literature values. The given methods are applicable to other oven types and heating modes.