Journal of Measurement, Control, and Automation

IPD, POD and APOD Multi-carrier PWM Techniques for Five-Level Nested Neutral Point Clamped Inverter

Thuong Tran — 2024-08-20

Recently, in order to develop high-voltage and large-capacity applications in industry and in the power grid, the NNPC type high-order inverter has been proposed. Simultaneously, pulse width modulation (PWM) control methods for these converters are also focused on research to provide high quality output voltage and current such as small current ripple, low harmonic distortion. Multi-carrier pulse width modulation (CBPWM) is an option due to its simplicity and ease of implementation. This paper studies the CBPWM techniques applied to the NNPC 5-level inverter. CBPWM techniques include in-phase disposition (IPD), phase opposition disposition (POD), and alternative phase opposition disposition (APOD). Because the inverter uses many flying capacitors, the problem of voltage balancing on the capacitors will be taken care of. The output voltage and current quality results of the load when using the CBPWM carrier methods: IPD, POD, APOD and applying the voltage balancing algorithm of the flying capacitors will be verified and evaluated. Simulation results with PLECS software. Finally, verification results from the experimental model of the 5-level NNPC inverter will confirm the correctness of the theoretical analysis and the designed capacitor voltage balancing algorithm.

Human Direction Determination for Visually Impaired Support Indoor Mobile Robot

Thi Ly Tong — 2024-08-20

Independent mobility is an essential part of the daily life of many visually impaired individuals. To assist them in navigation and improve their quality of life, various designs have been developed, including portable devices such as electronic canes, navigation suitcases, and guided robotic dogs. However, when it comes to indoor environments, constantly carrying an object alongside is not practical. Therefore, there have been numerous studies on mobile robot systems for navigation and assistance in indoor environments. One of the requirements for such a non-contact robot system is to determine the direction of the visually impaired individual to provide accurate assistance. This article focuses on developing algorithms for determining the direction of the object that needs assistance in indoor environments. The object's information is collected using a 3D camera, and then techniques such as object tracking, skeleton framework construction, and Gaussian filtering of depth images are used to calculate the object's direction angle. The proposed algorithm was tested with a representative sample of visually impaired individuals in a laboratory setting. The results showed high accuracy for static objects and acceptable performance for dynamic objects. This forms the basis for applying this algorithm to mobile robot systems that assist visually impaired individuals.

Improved Virtual Space Vector Modulation for Four-Level Nested Neutral Point Clamped Inverters

Nguyen Duc Khoa — 2024-08-20

The four-level diode-clamped NNPC (Nested Neutral Point Clamped) inverter configuration is employed in high-power electrical drive systems or medium-voltage applications due to its ability to ensure excellent output voltage quality while requiring fewer components compared to traditional four-level inverter configurations. The Sinusoidal Pulse Width Modulation (SPWM) technique applied to this converter is straightforward to implement but has a limited output voltage range. This paper presents a Novel and improved Virtual Space Vector Pulse Width Modulation (VSVPWM) with an average common-mode voltage. Compared to the sine-wave pulse width modulation method, this technique offers several advantages, such as enabling control of the entire space vector diagram and achieving low harmonic distortion in the output waveform. Control and balancing of the flying capacitors are achieved by utilizing phase-leg redundant states. The results of the control algorithm analysis for this inverter are validated through simulations using MATLAB/Simulink software and experiments conducted on a real-world model. The evaluations of the Total Harmonic Distortion (THD%), output current, and voltage across the flying capacitors demonstrate the high-quality performance of the converter within the full voltage range.

Control of the MMC converter for grid connection enhances noise immunity using LADRC control

Viet Phuong Pham — 2024-08-20

The MMC converter stands out as a promising solution for integrating distributed energy sources and HVDC systems with the grid. However, the inherent complexity of the MMC structure, characterized by a large number of submodule (SM) units, presents challenges during operation, particularly in direct modulation scenarios. These complexities manifest as dynamic processes that can induce interference, significantly impacting grid connectivity, especially in weak power grid scenarios. This paper presents a control solution aimed at mitigating linear active disturbances by leveraging the Linear Active Disturbance Rejection Control (LADRC) technique. The proposed controller, when integrated with the Nearest Level Modulation (NLM) method, enables the generation of 2N+1 AC voltage levels with low-frequency closing pulses for the valves. This approach shows promise in enhancing system stability owing to its robust anti-interference capabilities and superior tracking performance. The methodology is rooted in a small-signal impedance model that accounts for frequency coupling dynamics. The efficacy of the proposed solution is validated through simulations conducted by using Matlab/Simulink software.

Active vibration control by combining the independent mode space control solution and bounded state control solution

Thuy Nguyen Thi Bich — 2024-08-20

Adjusting construction vibrations is always a challenge for construction engineers. People have proposed many different control solutions, either by passive control, or by actively controlling the vibrations of the structure. In each control solution, there are many methods offered. In this article, the authors present a method combining the Independent Mode Space Control solution – IMSC and the Bounded State Control solution – BSC to solve the problem of active control of vibrations of an oscillating system with many degrees of freedom, taking the advantages of each solution to improve control efficiency such as the intuitiveness and simplicity of the BSC solution, and replacing the solution of the system of mutually constrained differential equations with the system of separate differential equations of the IMSC solution. The authors have relied on an example of active vibration control of a five-storey frame subjected to external loads to illustrate the method, clearly show the effectiveness of the method and provide necessary comments on the combination control method.

Development of Tank Model to Predict The Flow to Thac Xang Reservoir, Vietnam

Ha Van Thuy — 2024-08-20

Efficient operation of a water tank is pivotal in harnessing water resources and mitigating flood-related damages. Precise management of inflow rates to dam reservoirs is crucial for effective reservoir control. As a result, extensive research at both international and domestic levels has been conducted to develop and optimize flow forecasting models. This article presents a demonstration of rain shower forecasing and flow calculation using an established tank model. The model is implemented and visualized using MATLAB Simulink. To optimize and validate the model, data from hydropower reservoir studies are utilized. The proposed flow prediction model has been adjusted to achieve a correlation coefficient of 74.0%. This model was used to predict the flow rate in the period from 1971 to 1976 at Thac Xang hdroelectric reservoir, Vietnam with the correlation coefficient of 70.0%. This model predicted a flow rate trend that was quite close to the measured flow rate trend at the monitoring stations in this area. Although in this case, the correlation coefficient is not really high, the model can be applied to predict flow to effectively manage and regulate the water resources at Thac Xang hydroelectric reservoir, Vetnam

Simulation of the SAW sensor measuring magnetic fields using the transmission matrix model combined with FEM simulations

Phu Do Duy — 2024-08-20

This study proposes the transmission matrix model [ABCD] for the FeNi magnetic sensitive layer used in surface acoustic wave magnetic (SAW-MO) sensors. The center frequency and input excitation to the sensor through the v_m-H characteristic are determined by finite element simulation (FEM) on the FeNi/IDT/ST-Quartz structure. The simulation results of the center frequency and sensor's working response show that simulations by the FEM method and simulations by the transmission matrix (TM) method are correlated. Furthermore, the survey also indicates the more reasonable and suitable of the third-order v_m-H characteristic curve compared to the second-order characteristic in the transmission matrix model of the FeNi magnetic sensitivity layer. These accuracy and suitability are expressed through the trend and shape of the sensor's working response.

Control Autonomous Mobile Robot for Firefighting Task

Pham Thuc Anh Nguyen — 2024-08-20

Fire plays an indispensable role for humans. However, fire accident is one of the leading hazards endangering human life and health, leads to unpredictable loss to the economy, and destroy the environment. Fire accident may happen anywhere, when fires outbreak will push the firefighters on duty facing with dangers. Research and development of firefighting robots to replace firefighters becomes necessary. In general, firefighting robots are required to be able to move on chaotic and constantly changing terrain, avoid obstacles, detect and approach to fire areas, extinguish firea and save victim. In this research, we have designed and manufactured a belt-driven mobile robot capable of moving on a number of variable terrains, integrated with a machine vision system to detect and identify fires. PLC-based controller is responsible for control the robot to approach the fire areas and avoid obsstacles. Experiment work has been conducted and results showed the accuracy of fire detection and an ability of the proposed robot in performing the required firefighting activities.

Adaptive Gait Generation for Spider Robots Using NARX Model Combining Evolutionary Neural Network Model

Dat Nguyen Tien — 2024-08-20

Dáng đi đóng vai trò quyết định về hiệu suất đi bộ của robot có chân. Hiện nay, tạo dáng vẫn là bài toán rất khó vì kỹ thuật hiện tại chưa tiếp cận được một cách chi tiết về kết cấu vô cùng phức tạp và sự vận động rất tinh vi của các động vật có chân. Bài báo này, đề xuất mô hình tạo dáng đi (WPG) để robot nhện bước đi thẳng bám theo quỹ đạo ZMP tham chiếu được thiết kế trong 2 chu kỳ bước với hai tốc độ khác nhau. Đầu tiên, mô hình mạng nơ-rôn tiến hoá hồi quy phi tuyến (NARX+EANN) được thiết kế để nhận dạng các tham số dáng đi của spider robot và cấp cho bộ tạo mẫu đi bộ (WPG). Kế tiếp, bộ tạo mẫu dáng đi (WPG) mới chỉ phụ thuộc vào bốn tham số (chiều dài bước, độ nhấc chân, độ khụy gối, độ sải chân) của robot nhện kích thước nhỏ được thiết kế, bằng cách dựa vào phân tích dáng đi thực tế của robot nhện và phân tích động học. Đồng thời, 12 quỹ đạo góc khớp tại bốn chân của robot nhện sẽ được xác định từ quỹ đạo của hông và quỹ đạo của bàn chân tại bốn chân của robot nhện thông qua giải bài toán động học ngược bằng phương pháp giải tích. Sau đó, các trọng số tối ưu của mô hình NARX+EANN được nhận dạng bằng cách sử dụng thuật toán tối ưu Jaya để huấn luyện với hàm mục tiêu là cực tiểu hoá tổng sai số giữa tọa độ ZMP thực tế với ZMP tham chiếu trong hai chu kỳ bước có tốc độ khác nhau. Điểm ZMP thực tế được xác định bằng cách dựa vào 12 quỹ đạo góc khớp tại bốn chân của robot nhện thông qua giải bài toán động học thuận sử dụng phương pháp giải tích. Cuối cùng, đề xuất này được áp dụng vào mô hình thực nghiệm robot nhện B3-SBOT. Kết quả thu được chứng tỏ rằng B3-SBOT bước đi vững chắc và mạnh mẽ mà không nghiêng ngã theo sát quỹ đạo ZMP tham chiếu được thiết kế trong 2 chu kỳ bước với hai tốc độ khác nhau.