Hoai-Hung Khong

Dr. Hoai-Hung Khong

Ho Chi Minh City University of Transport, Faculty of Electrical and Electronics Engineering,
orcid

Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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21 February 2020 in Electronics
Verified
Journal Article
Open access
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HKHoai-Hung Khong
Hoai-Hung Khong
SCSeng Chi Chen
Seng Chi Chen
HTHoang Than
Hoang Than
This paper presents the sensorless control algorithm for a permanent magnet synchronous motor (PMSM) drive system with the estimator and the intelligent controller. The estimator is constructed on the novel sliding mode observer (SMO) in combination with a phase-locked loop (PLL) to estimate the position and speed of the rotor. The intelligent controller is a radial basis function neural network (RBFNN)-based self-tuning PID (Proportional-Integral-Derivative) controller, applied to the velocity control loop of the PMSM drive control system to adapt strongly to dynamic characteristics during the operation with an external load. The I-f startup strategy is adopted to accelerate the motor from standstill, then switches to the sensorless mode smoothly. The control algorithm program is based on MATLAB and can be executed in simulations and experiments. The control system performance is verified on an experimental platform with various speeds and the dynamic load, in which the specified I-f startup mode and sensorless mode, inspected by tracking response and speed regulation. The simulation and experimental results demonstrate that the proposed method has worked successfully. The motor control system has smooth switching, good tracking response, and robustness against disturbance.

24 August 2020 in Electronics
Verified
Journal Article
Open access
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HKHoai-Hung Khong
Hoai-Hung Khong
SCSeng Chi Chen
Seng Chi Chen
CCChin-Feng Chang
Chin-Feng Chang
A neural fuzzy controller (NFC)-based speed controller for the sensorless permanent magnet synchronous motor (PMSM) drive control system is realized in this paper. The NFC is a fuzzy logic controller (FLC), which adjusts the RBFNN-based (radial basis function neural network) parameter by adapting the dynamic system characteristics. For sensorless PMSM drive, the integration of sliding mode observer (SMO) and phase-locked loop (PLL) is executed to estimate the rotor position and speed. To eliminate the initial rotor position estimation and overcome the conventional PLL-based position estimation error in the direction reversion transition, the I-f control strategy is applied to start up the motor and change the rotational direction effectively. The system performance was verified in various experimental conditions. The simulation and experimental results indicate that the proposed control algorithm is implemented efficiently. The motor starts up with diverse external loads, operates in a wide speed range for both positive and negative directions, and reverses the rotational direction stably. Furthermore, the system presents robustness against disturbance and tracks the command speed properly.

14 March 2022 in Applied Sciences
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Journal Article
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DPDwi Putra
Dwi Putra
SCSeng Chi Chen
Seng Chi Chen
HKHoai-Hung Khong
Hoai-Hung Khong
FCFred T Cheng
Fred T Cheng
Information about rotor positions is critical when controlling a permanent-magnet synchronous motor (PMSM). This information can be gathered using a sensor or through an estimation without using a sensor. This article discusses a machine learning technique for estimating rotor positions. The proposed machine learning observer was constructed using a modified Elman neural network as the main algorithm. The network was trained offline with training data obtained from PMSM field-oriented control simulations and was tested using a validation data set. The PMSM control simulation results revealed that the rotor position estimated through machine learning was comparable with the simulated rotor position; the average error was 0.0127 per unit position. Furthermore, the machine learning model was implemented in an experimental PMSM-control hardware platform. Both the simulation and experimental results indicate that the proposed machine learning observer has an acceptable performance.

1 May 2019
Verified
Conference Paper
Closed access
SCSeng-Chi Chen
Seng-Chi Chen
HKHoai-Hung Khong
Hoai-Hung Khong
The paper presents a method to build an Adaptive Fuzzy PID Controller for a three-phase PMSM with a Field Oriented Control (FOC). However, there are many different approaches to design and code the program. This is dependent on the systems hardware. The Texas Instrument DSP is normally used in conjunction with the CCS environment which requires C languages skill. To simplify the process and reduce coding time, this paper recommends a new method to design the algorithm based on the Embedded Coder and the Fuzzy Logic Designer Toolbox in MATLAB. The results were verified on the platform with the F28069 Control Card and loaded conditions.


5 March 2023 in Mathematics
Verified
Journal Article
Open access
PDF file
DPDwi Putra
Dwi Putra
SCSeng Chi Chen
Seng Chi Chen
HKHoai-Hung Khong
Hoai-Hung Khong
CCChin-Feng Chang
Chin-Feng Chang
An observer is a crucial part of the sensorless control of a permanent magnet synchronous motor (PMSM). An observer, based on mathematical equations, depends on information regarding several parameters of the controlled motor. If the motor is replaced, then we need to know the motor parameter values and reset the observer’s parameters. This article discusses an intelligent observer that can be used for several motors with different parameters. The proposed intelligent observer was developed using machine learning methods. This observer’s core algorithm is a modified Jordan neural network. It processes Iα, Iβ, vα, and vβ to produce Sin θ and Cos θ values. It is combined with a phase-locked loop function to generate position and speed feedback information. The offline learning process is carried out using data acquired from the simulations of PMSM motors. This study used five PMSMs with different parameters, three as the learning reference sources and two as testing sources. The proposed intelligent observer was successfully used to control motors with different parameters in both simulation and experimental hardware. The average error in position estimated for the simulation was 0.0078 p.u and the error was 0.0100 p.u for the experimental realization.