An Inequality Indicator for High-Resistance Connection Fault Diagnosis in Marine Current Turbine

Abstract

Marine current energy is an abundant renewable energy resource. Marine current turbines (MCTs) can convert the kinetic energy of marine currents into electrical energy. However, the variations in the marine currents are violent and complex. These characteristics will be reflected in the variation in the operating condition of MCTs, thus interfering with normal diagnosis for the high-resistance connection (HRC). The HRC can be caused by damaged connections between device components that are easily made due to the harsh marine environment. To diagnose HRC in MCT, an inequality indicator is proposed to quantify the current imbalance caused by HRC. The inequality indicator is defined based on the arithmetic–geometric mean inequality and can identify slight current imbalances in the early stages of HRC. The inequality indicator is robust to the variable operating conditions of the permanent magnet synchronous machine (PMSM) in the MCT. Experimental results show that the inequality indicator can be used to effectively diagnose HRC in the MCT with 100% accuracy. This research will help maintain the health condition of the MCTs and provide some ideas for diagnosis in MCTs. Moreover, the inequality indicator may provide a different approach to the analysis for other faults that can lead to a current imbalance.

High-Resistance Connection Fault Diagnosis in Ship Electric Propulsion System Using Res-CBDNN

“…The HRC fault of the ship propulsion system, which usually occurs between the drive inverter circuit and the propulsion motor, is a discontinuous early gradual fault [18], and its failure schematic is shown in Figure 2. The main distribution board is composed of the generator control panel, synchronous panel, load panel, and bus bar.…”

“…The HRC fault of the ship propulsion system, which usually occurs between the drive inverter circuit and the propulsion motor, is a discontinuous early gradual fault [18], and its failure schematic is shown in Figure 2. The mathematical model of the propulsion motor under HRC fault can be expressed as follows: N is the pole of the motor.…”

Active Disturbance Rejection Control Method for Marine Permanent-Magnet Propulsion Motor Based on Improved ESO and Nonlinear Switching Function

“…However, the permanent-magnet synchronous motor is a typical nonlinear and strongly coupled system [4,5], which is difficult to described with an accurate mathematical model. The permanent-magnet synchronous motor is susceptible to various load changes, external sea state changes and parameter changes, and the long-term operation of the motor system in a high-salt, high-temperature, and high-humidity marine environment will lead to problems such as the reduction of sensor accuracy [6,7]. The traditional PI control method cannot meet the requirements of high-performance control of marine propulsion motors; so, it is necessary to use nonlinear controllers to improve their tracking and anti-disturbance capabilities.…”