This paper proposes a thermal network parameter estimation method for insulated-gate bipolar transistor (IGBT) modules using the junction temperature cooling curve. The proposed finds RC parameters of fourth-order Cauer by establishing relationship between and time constants response curves. Experimental tests are performed to validate accuracy developed method. Results show that difference total resistance IEC standard is below 2%. Advantages over existing methods does not need 1) know...

The forced air cooling system plays an important role in the safe operation of power converters. Condition monitoring its health status can improve reliability converter and reduce cost unscheduled maintenance due to over-heating. This letter proposed use natural frequency thermal network as indicator monitor aging process system. We show that degradation be monitored by detecting variation frequency. Experimental tests on a three-phase dc/ac with are performed verify effectiveness method....

Purpose This paper aims at the problem of surrounding rock excavation damage zone tunneling in rich water region, this to propose a new seepage-stress-damage coupling model and studied numerical algorithm. reflects characteristics evolution, accompanied by plastic flow deformation multi-field interaction. Design/methodology/approach First all, elastoplastic constitutive based on Drucker–Prager criterion is established, fully implicit return mapping algorithm adopted realize solution. Second,...

Classification of the surrounding rock is basis tunnel design and construction. However, conventional classification methods do not allow dynamic construction adjustments because they are time‐consuming consider randomness mass. This paper presents a new reliability mass method based on least squares support vector machine (LSSVM) optimized by bacterial foraging optimization algorithm (BFOA). The LSSVM adopted to express implicit relationship between indicators grades, which response surface...

In this paper, vibration control of flexible-link manipulators is considered. A nonlinear partial differential equation describing the dynamics a two-link planar manipulator with flexible forearm derived. Thereafter, utilizing eigenfunctions corresponding to boundary value problem at hand, finite-dimensional approximation model given. The controller design strategy based upon an inner-loop which corresponds rigid body motion taking into consideration vibrations and outer-loop for further...

The cooling system, including the thermal grease, heatsinks, plays an important role in power converters for its reliable operation. While long-term operation situation, system will degrade with different kinds of failure mechanism components and finally result damage to converters. In this paper, method was proposed monitor network parameters using curves junction temperature. By establishing relationship between RC Cauer time constants curves, about can be obtained. Experimental tests are...

The randomness of rock joint development is an important factor in the uncertainty geotechnical engineering stability. In this study, a method proposed to evaluate reliability intermittent jointed slope. least squares support vector machine (LSSVM) evolved by bacterial foraging optimization algorithm (BFOA) used establish response surface model express mapping relationship between parameters and slope safety factor. training samples are obtained from numerical calculation based on finite...

In view of the difficulty in measuring kinematic velocity and high frequency (HF) environmental disturbance ship dynamic positioning system (DPS), a method proportional-derivative (PD) control compensated by nonlinear passive observer has been proposed. Through force estimated acting on bias compensation control, not only can response speed closed-loop be improved, but also negative effects system-controlling precision thrusters-acting frequency, most which are caused HF disturbance,...

In [1], we proposed a method for identifying the Cauer type thermal parameters based on junction temperature's cooling curve of IGBT module during shutoff period. This paper utilized identification in [1] to realize condition monitoring. Experimental tests are performed validate feasibility and accuracy this approach. Results indicate that identified RC can be used monitoring aging power device.

Thermal grease gets generally application in power device, for its high-efficient thermal conducting performance. While the long-term operating situation, will degrade with pump-out and dry-out phenomenon do harm to heat dissipation of devices, so it is necessary monitor states grease. In this paper, we propose a method resistance using cooling curves junction temperature. By establishing relationship between RC parameters Cauer network time constants curves, about can be obtained....

Abstract During the construction of elevated bridge pile foundations, mechanical processes, including extrusion and friction caused by steel casing's rotation into soil pressure unloading due to extraction from holes, can significantly disturb existing structures. To address engineering challenge posed planned on Yuanjiang Street Expressway in Shenyang, which is adjacent operational Metro Line 10 Dingxianghu Station, this study investigates disturbance laws foundation behavior metro station....

Wind-thermal-bundled power transmission by UHVDC system is regarded as one feasible way of developing global clean energy in the future and its characteristic stability should be paid attention to. Different wind-thermal installed capacity ratio proposed with wind from change angle consideration probability for output. The effect two kinds proportion on sending end islanded was comparatively analyzed simulation. Regulating ability would lower when decreased 1:2 to 1:1.5. Under DC...

In order to avoid the situation that diagnosis model based on single sensor data is easily disturbed by environmental noise and accuracy low, an intelligent fault fusion method for marine diesel engine proposed. Firstly, support vector machine which optimized genetic algorithm used learn sample from different sensors, then multiple models results can be got. After that, groups of are taken as evidence bodies fused theory obtain more accurate results. By analyzing obtained simulation...

Hybrid electric vehicles have excellent energy efficiency and emission performance. Power split device (PSD) is a key component that directly affects the control strategy of power systems, economic consumption fuel, dynamic performance vehicles. A differential-based PSD was proposed in this paper. traditional differential taken as prototype new design method to retrofit into PSD. First, comprehensive approach includes theoretical analysis software simulation used analyze possibility well...

Wind-thermal-bundled power transmission by UHVDC system is regarded as one feasible way of developing global clean energy in the future and its characteristic stability should be paid attention to.Different wind-thermal installed capacity ratio proposed with wind from change angle consideration probability for output.The effect two kinds proportion on sending end islanded was comparatively analyzed simulation.Regulating ability would lower when decreased 1:2 to 1:1.5.Under DC disturbances...

Due to the geological body uncertainty, identification of surrounding rock parameters in tunnel construction process is great significance calculation stability. The ubiquitous-joint model and three-dimensional numerical simulation have advantages parameter with weak planes, but conventional methods certain problems, such as a large number time consumption. To solve this study combines orthogonal design, Gaussian (GP) regression, difference evolution (DE) optimization, it constructs method...

Rock blasting often has an irreversible impact on the surrounding environment and threatens safety of life property. Therefore, accurate prediction blast‐induced ground vibration (BIGV) is a prerequisite for safe construction. In view fact that traditional peak particle velocity (PPV) empirical formulas cannot be accurately predicted, this study selected 88 sets monitoring data, based distance from blast‐face, maximum charge per delay, total charge, hole depth, spacing, burden, stemming...

This paper built 5 KVA / 400 Hz medium frequency power supply AC - DC main circuit, Output filter is designed in detail. Based on SPWM control strategy and the voltage RMS feedback loop PI adjustment, Matlab/Simulink simulation model established, Harmonics are analyzed, conclusion obtained.

In this research, a storage system, suitable for the power system of construction, is proposed and optimized. The mainly consists control converter, flywheel motor. This can release pressure grid during on-peak period supply consumers with cheap energy. research going to analyze characters then adjust its structure architecture.

The temperature of agricultural film unit affects the plastic directly. Since heating process has characters time delay, nonlinear, time-varying and strong coupling. It is difficult to create a mathematical model structure melting process. Thus, control very difficult. This paper presents decoupling strategy corresponding algorithm based on PID (proportional-Integral-differential) neural network. Proportional, integral, differential neurons form three-layer design gives full play respective...