Concerns of the impact of greenhouse gasses (GHG) are leading heavy industry users to explore energy reduction strategies such as the conservation of electricity use in ventilated machines by the use of variable-cooling systems. For these strategies to be implemented, a thermal model of the system is required. This study focuses on the thermal modelling of through-ventilated, industrial, electric machines that employ a variable-cooling strategy, using only on-line data collected during regular machine operation. Two empirical thermal models were developed: a first-order model, and a second-order model which was extended from the first-order based on its performance. By means of an energy-balance, the first-order model was able to define an estimation of the motor temperature based on only a single variable, and thus was able to be fit directly to complete process-cycle data to determine the parameter. Over the 18 process-cycle samples, this parameter was found to vary by as much as $\pm$10\%, therefore, when a generalized model was proposed using the median value of the parameter, the maximum error seen over the process cycles was 9.0 $^{\circ}C$, with a maximum average error over a process-cycle of 4.2 $^{\circ}C$. An effort was made to determine the effects of reduced cooling on the model by performing reduced-cooling experiments during machine cool-downs, however the thermal-time constant, which directly relates the heat-transfer rate to the system capacitance, was found to vary by as much as 47\%, suggesting that the system's capacitance was changing, and that the first-order model was not accurate enough to distil these effects. A key obervation of the performance of the first-order model was that in heating it would under-predict the machine temperature, and in cooling would over-predict, suggesting that an additional heat-transfer path existed to the cooling air through some additional thermal capacitance. In an effort to include higher-order effects so that reduced-cooling effects could be established, a second-order model was developed by adding an additional lumped-node to the system, introducing the supposed additional conduction/capacitive path, where the heat-generating node was considered analogous to the motor's armature, and the additional node was considered as a thermal-sink. This model was then numerically fit to the cool-down data for both maximum and reduced flow-rate cases in order to identify the system's main heat transfer parameters, however, once again, a large variance in the parameters was found. Through model simulation, this was determined to be the result of the system not starting at a steady-state temperature distribution, which resulted in the parameter estimation under-predicting the true values. As such, the upper-limits of the parameter spreads were used to identify the model. Assuming the system's heat generation was due to Joule-losses only, the second-order model was found to perform marginally better than the first-order model, with a maximum error of 8.6 $^{\circ}C$, and a maximum average error of 3.3 $^{\circ}C$ over the process-cycles. Though the second-order model typically performed better than the first-order model in cooling, it was found that the model would vary between over-predicting and under-predicting the machine temperature, indicating that additional and higher-order core losses may play a role in the heating of the machine. Although the first-order model was found to be slightly less-accurate than that of the second-order, the first-order model has a much simpler and far less intrusive identification scheme than that of the second-order model with a relatively low loss in accuracy. As a result, it would be possible to to use the first-order model for on-line temperature monitoring of the machine by performing tests during operation where the cooling rate is reduced to identify the change in the model parameter. However a sufficient factor of safety ($\approx$10 $^{\circ}C$) would be required to account for the under-estimation that occurs in heating. For the second-order model to be implemented, more controlled testing is required in order to properly discern the effects of reduced cooling from the effects of the initial temperature distribution. Additionally, the inclusion of core-losses in the machine heat generation term should be investigated to improve model performance. / Thesis / Master of Applied Science (MASc)

The thesis describes a novel 4-quadrant DC-DC converter, supplied by a 28V DC voltage source, with an output voltage which may be continuously varied between +180V and -180V DC. A prototype 1.2kW DC-DC converter was designed and built, with emphasis given to the optimization of both the converter size and efficiency. This was achieved by means of a computer-based simulation study, which determined the optimal switching frequency and the size of the inductors and capacitors while maintaining a high unit efficiency. Mos-Gated Bimos switches, which feature the advantages of both mosfets and bipolar transistors, were developed to achieve high switching speed during high power operation. A digital-controlled DC servo system based on a 16-bit Intel 8086 microprocessor was designed, to provide both motor speed and position control. Speed and position detection circuits and the structure and the interfacing arrangement of the microprocessor system were designed and constructed. Several control algorithms were developed, including PID Control Algorithm and Current-Limit Control Algorithm. Based on open loop transfer function of the system, derived through mathematical modelling using the State-Space Averaging Method, the constants for the control algorithms were obtained to meet the dynamic performance specified for the system. Computer simulation was carried out to assist with the design of the converter and the control system. It is expected that drives into which the novel converter is incorporated will find many applications in situations where accurate positional control is required, particularly in battery-operated DC-servo system, such as satellite system, robots and some military vehicles.

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The TI TMS320LF2407A DSP is used as the control kernel in this thesis, proposing a method of sensorless control for the brushless DC motor. With six-step pulse-width modulation, the information of the back electromagnetic signals can be detected and is used to estimate the rotor position instead of the Hall sensors. To strengthen the system and reduce the power consumption, we propose the idea of close loop framework, including speed feedback and current feedback. Then, the phase-change signal is set as no delayed, 15 degree delayed, and 30 degree delayed and compare the results each other. Finally, setting up experimental framework, to verify the superiority of sensorless drivers with close-loop framework, and choosing better phase-change degree to improve system and efficiency.

<p>A control system for a BLDC (Brushless Direct Current) motor has been developed in Labview 2009. This report explains how it works, conclusions and some information about things that could have been done differently. This report is also a good introduction to Labview including its advantages and disadvantages. It also explains how a FOC (Field Oriented Control) works.</p><p>This is the public version of the report which does not include any results or information about the implementation. This information can be found in the original report which only authorized persons have access to.</p>

A control system for a BLDC (Brushless Direct Current) motor has been developed in Labview 2009. This report explains how it works, conclusions and some information about things that could have been done differently. This report is also a good introduction to Labview including its advantages and disadvantages. It also explains how a FOC (Field Oriented Control) works. This is the public version of the report which does not include any results or information about the implementation. This information can be found in the original report which only authorized persons have access to.

Abstract In this bachelor thesis we focus on how the computer software LabVIEW test is used to a DC-motor through as a hardware incremental encoder and a USB-6009. By using LabVIEW, we can do pulse counting, voltage changing test, voltage signal acquiring and some other observing jobs. This paper is a report of our mechanical operation and calculative work about the DC motor as well. The using DC motor's model number is E-660. Since we cannot find the official data of the DC motor we need, we tried to find some similar motor model to compare. Fortunately, we find some data. Even it is unofficial data from eBay website. However, these data can be seen as reference of our motor. Therefore we can compare the data from the laboratory and the theoretical ones. For the other part of the thesis is about the incremental encoder, the model we used in project is DG 63 KA. We just can find a similar type and it as a reference. The model we find similar to the actual one is DG 60L and through the measurement and comparison, we manage to test the encoder pattern is the same as the reference.     Eventually, we can still do some calculations and analysis with the measured data. We also can summarize some content according to the referential data with the similar DC motor. / 摘要 在此学士论文中我们主要将重点放在LabVIEW电脑软件测试如何通过硬件设备增量式编码器和USB-6009应用到直流电机上。通过使用LabViEW， 我们可以进行脉冲计数，电压变化测试，电压信号采样和其它观测工作。 这份报告同时也包括对直流电机的机械操作和计算工作。我们使用的直流电机型号为E-660。由于我们未能找到我们需要的直流电机的数据，我们尝试去找到一些相似的型号来比较。幸运的是，之后我们找到了一些数据。尽管数据是来自eBay的非官方数据。然而，这些数据可以作为我们电机的参考。因此我们可以使用这些理论数据和我们从实验得出的数据进行比较。 论文的另外部分是关于增量式编码器，我们在论文中使用的编码器型号是DG 63 KA。我们只能找到一些类似型号作为参考。我们找到的和实际使用的类似编码器型号为DG 60L 并且通过测量和比较，我们成功证实编码器的模式和参考中的相同。 最终，我们还对测量的数据进行了计算和分析。我们同时也根据类似的直流电机的参考数据进行总结。

This thesis focuses on compact brushless DC fan motor, drive circuit structure of motor is proposed, several functions such as output low current limit circuit and low rotation speed limit are added in order to increase robustness of drive circuit. Besides, speed feedback controller is used to solve several problems such as high frequency full speed exciting noise and high power dissipation which occurs in open loop rotation speed control circuit.With regard to BLDC fan motors generally use Hall sensor to detect rotor position, this research proposes sensorless control technology for the purpose of reducing circuit cost and motor size.

This thesis focues on the realization of small size brushless DC fan motor driving circuit, adding the protection circuit of commutation to H bridge, in addition, the function of low current limiter, and slow rotation speed limiter are also implemented to the more stable rotation. With regard to the strategy of rotation speed control, we use speed feedback controller to slove noise problem which occurs in high frequency full speed excited and adopt thermistor accompanied with the voltage divided circuit to achieve speed control with temperature. Finally, for the sake of reducing the cost and shrinking the size of system, the design of sensorless mode is proposed and the rotation speed control system is realized under sensorless mode.

In order to provide the means to set up a control theory lab experiment involving position control of a brushed DC motor with current feedback, a pulse-width modulated motor controller was designed. The output voltage is controlled by an analog reference signal and the magnitude of the output current and voltage are measured and output. These inputs and outputs are connected to a DAQ I/O-unit such that the lab experiment can be implemented digitally. In addition, defining equations for the whole system were derived. Comparison between measurements and model showed it possible to use the current as feedback if low-pass filtered and the angular displacement controlled over a small angular interval.