Essentials Of Systems Analysis & Design – From Cooperation to Hegemonic Water Management through Dualism and Jeong: Lessons Learned from the Daegu-Gumi Conflict in Korea
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Essentials Of Systems Analysis & Design
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Received: 2 November 2018 / Revised: 19 November 2018 / Accepted: 23 November 2018 / Published: 26 November 2018
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This paper presents a new design for a single-stage active power harmonic filter (APHF) with simple and flexible control to eliminate harmonics and low-level network effects. The proposed APHF consists of an accurate harmonic detector circuit, an amplifier circuit to trap minor harmonics, a switching driver circuit for precise timing, and an inverter to generate a current waveform that can be obtained from the signal. The control circuit is based on an electrostatic device with an operational amplifier circuit. Fast dynamics, simplicity, low cost and small size are the main characteristics of the Op-Amp circuit that is used in the proposed topology. The goal is to eliminate all sets of coherent networks in which APF introduces appropriate network propositions in parallel. The proposed control system is intelligent enough to compensate for the range of harmonic current. A prototype was installed in the Power Electronics laboratory and installed in parallel with a network driven by a non-linear load (15 A
) to check the harmonic compensation. The harmonics are compensated from THD% = 24.48 to THD% = 2.86 and the non-sinusoidal waveform is updated to the sinusoidal waveform of the proposed APHF. The test results show good performance and good quality.
The increasing application of semiconductor devices and non-current loads in industrial, residential and commercial areas has led to surges and current ripples that cause harmonic distortion in of the power system [1, 2]. Harmonics in the power grid cause harmful damage, such as loss of power, overloading, reduction of power quality, degradation of equipment and interference with the operation of materials [3, 4, 5, 6].
Therefore, it is necessary to identify harmonics and find strategies to eliminate them and reduce them to an acceptable standard. For many years, passive filters have been the common solution to reduce harmonic pollution [7, 8, 9, 10, 11]. Many power supply converters (PFCs) can reduce harmonics. A family of single-phase and hybrid PFC converters was introduced in [12, 13]. In [14] a three-level single-phase PFC rectifier topology is presented. Other topologies discussed the number of outputs for the PFC converter [15].
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PFC converters usually have low power (PF) and harmonic failure due to the dead angle of the input, especially in the low/output area [13]. The active power harmonic filter (APHF) has been proposed as a solution for power electronics, because passive filters have many disadvantages [16, 17, 18, 19]. The ability to intelligently control active harmonic filters is a major advantage [20]. As an ideal harmonic detection device, it can be installed in various scales with balanced loads to prevent harmonics from spreading in the network so that the network remains in the sinusoidal wave [21, 22, 23, 24]. The wide application of this tool is effective in improving the power quality of the network [25, 26, 27, 28, 29, 30]. The active filter produces the same (but opposite) harmonics by controlling the harmonics of the electrical load, which prohibits the current harmonics from traveling through the power line [31, 32 ].
Active power harmonic filter as a compensator is divided into two parts: (1) power circuit; and (2) control circuit (harmonic detector algorithm for rotation control). Faults in individual sections and improper connections not only lead to poor compensation performance, but also increase harmonic components that reduce power quality [33]. An accurate harmonic detector algorithm and processing scheme can reduce the cost of the power component structure. Therefore, there are many articles in the control module, harmonic detection and switching. Most papers deal with program-based control systems, especially transfer functions and DQ-axis transformations (direct quadrature) [34, 35, 36, 37, 38]. Search algorithms [39, 40] were also used. The authors in [41] study load prediction for power quality control. Although microprocessors will reduce the complexity of the control circuit, but the quality of the sample signal is reduced due to analog / digital conversion, some coding algorithms are not effective, the results are slower in simple calculations. , and the high cost should be considered compared to electrostatic circuits [42]. , 43, 44]. On the other hand, the rapid response of the electrostatic circuit for simple calculations and easier than microprocessors can increase the efficiency of the control circuit. In addition, the removal of microprocessors makes the circuit simpler, which can be expected to reduce the overall cost of the application [45, 46, 47, 48]. Another major challenge at APHF is transitioning and adapting to the current network. Additional network failures are expected if there is no correct alignment of signal signals. Fast processing and accurate timing are some features of hysteresis processing techniques that are used in high-speed electrostatic circuits [49, 50].
In this article, active harmonic filter control strategies are presented using electrostatic devices and Op-Amp circuits that enable the removal of microprocessors and programming devices. The elimination of microprocessors reduces the complexity of programming and A/D conversion and the quality distortion of the sampled APHF signal. The sensor sensor (sample) is also removed in the proposed control strategy due to the hysteresis transition with a well-defined time. In this way, the cost of the application can be reduced, although the performance quality is increased through fast dynamic response and accurate cancellation of harmonics. The proposed topology can be used by electricity consumers for residential, commercial and small industries. The operation of the proposed controller is as follows: the load is sensed by the current sensor which is affected by the harmonics. Harmonics are then extracted from the proposed Op-Amp circuit with fast dynamic response. The extracted signal is amplified in the amplifier circuit because high frequency harmonics can be received in the distortion model. This greatly increases the quality of APHF compensation. Section 2 presents these issues. Hysteresis and timing are defined in Section 3. Experimental results are presented in Section 4 to verify the performance of various parts of the proposed control circuit and APHF compensation.
Some properties in the control area should be considered, such as the intelligent extraction of harmonics, the adjustment of the height and phase for the reference signal, the residual quality of the fundamental harmonic sequence (1) after the APFH function, and the simple structure. Perfect expression of each of these properties leads to overall results consistent with APHF.
Embedded System Design
Figure 1 presents a simple, high-quality circuit for a high-pass filter with a precise step to remove harmonics from the network. The sample signal (from the current sensor network) is sent to the input circuit via V
And the circuit acts as a high-pass filter based on capacitor and resistor values. Therefore, it isolates all harmonics that are higher than the cutoff frequency and the circuit reveals them at the output (V
This proposed circuit consists of an operational amplifier. Other electronic devices (resistors, capacitors, diodes, etc.) in different arrangements can be connected to amplifiers that can be used for different tasks and applications. This high-pass filter is designed based on an operational amplifier and the cutoff frequency is set to separate higher frequencies than the fundamental component. This area has a very precise function
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