118 results about "Thermal network model" patented technology

The invention discloses a method for estimating junction temperature on line by an IGBT (Insulated Gate Bipolar Transistor) power module. The method comprises the following steps: estimating the junction temperature by using a thermo-sensitive electrical parameter method; establishing an extended state space thermal model; and applying a Kalman filter in junction temperature estimation. The thermosensitive electrical parameter method can estimate the junction temperature of an IGBT power module in real time, an IGBT conduction voltage drop VCE (ON) is selected as a thermosensitive electrical parameter, and a VCE (ON) online measurement circuit is provided. On the basis of a Foster thermal network model, the influence of diode coupling is considered, and an extended state space thermal model comprising self-heating and coupling heat is provided; And taking the power loss of the diode and the IGBT and the junction temperature estimation value obtained by using the thermosensitive electrical parameter method as the input of the Kalman filter, and considering the measurement noise and the process noise, thereby obtaining the optimal junction temperature estimation value. According to the method, electrical insulation is achieved, measurement is carried out without changing a control strategy of the power converter, noise is reduced, the intermittent influence of voltage measurementis eliminated, and the junction temperature measurement precision is improved.

The invention discloses a cophase power supply system flow controller dynamic reliability evaluating method. The influence of the actual traction load randomness and impact on the junction temperature fluctuation of a power element is taken into account. Power loss and a thermal network model are used to calculate the junction temperature of the power element. A physical model based on a failure mechanism and a linear fatigue damage cumulative model are combined to calculate the power module failure rate of a flow controller. The PFC reliability is analyzed by using a dynamic reliability assessment method which takes into account the variation of the element failure rate. According to the invention, the redundancy of a power module is analyzed; the number of cascaded modules of the flow controller is optimized; and a necessary basis is provided for engineering design and operation maintenance of a cophase power supply system.

The invention discloses an IGBT module health state monitoring method based on a natural frequency of a thermal network. The IGBT module health state monitoring method comprises the steps of: establishing a fourth-order equivalent Cauer thermal network model according to physical performance parameters of an IGBT module and a radiator; establishing a mapping relationship between the natural frequency of the thermal network and parameters of each order in the thermal network model according to an order-of-magnitude difference between the thermal parameters of each order; fitting a measured junction temperature cooling curve of the IGBT module to obtain the natural frequency of the thermal network; and monitoring a health state of the IGBT module according to the natural frequency. The IGBTmodule health state monitoring method can monitor the aging degree of the IGBT module under the condition that the power loss of the IGBT module is not measured.

The invention discloses an optimized power flow calculation method based on a multi-energy coupling model. The method comprises the following steps of establishing a multi-energy coupling model covering a power grid model, a heat supply network model and a cold network model based on CIM standard model expansion; determining optimal operation conditions of the electric energy equipment, the heat energy equipment and the cold energy equipment under different operation scheme modes to serve as input for optimizing load flow calculation; and determining the output of each source end device and the energy flow distribution of each energy network through the optimized power flow calculation. According to the method, the multi-energy complementary energy internet model is constructed, complementation of different energy sources is achieved through modeling of the multi-energy coupling equipment, and the method is easy and convenient to calculate, high in operability and high in practical application value.

A method for predicting the junction temperature of three-dimensional resistance-capacitance thermal network of asymmetric half-bridge power convert features that the junction temperature of the three-dimensional resistance-capacitance thermal network is predicted by using the junction temperature of the three-dimensional resistance-capacitance thermal network of asymmetric half-bridge power converter. In this method, the junction temperature of power devices in asymmetric half-bridge power converters under different loads is predicted. The junction temperature coupling and boundary conditiondecoupling are taken into account, and a three-dimensional resistance-capacitance thermal network model is established to realize the effective junction temperature prediction of power devices. Firstly, the transient loss distributions under different load conditions are obtained in asymmetric half-bridge power converters. Secondly, the finite element model of asymmetric half-bridge power converter is established, and the coupling thermal impedance and boundary decoupling thermal impedance are extracted according to the finite element thermal stress simulation with the transient loss as the input of thermal load. Then, the expressions of coupled thermal impedance and heat dissipation boundary conditions are obtained by means of electrothermal analogy theory and curve fitting. Finally, a three-dimensional resistive-capacitive thermal network model is constructed to predict the junction temperature of the power device by using the controlled voltage source to represent the thermal coupling impedance relationship and the sub-radiator thermal impedance to represent the different thermal boundary conditions.

The invention discloses a crimping type IGBT thermal network model modeling method and a related device. The method includes: constructing a three-dimensional model based on the entity crimping type IGBT, importing the three-dimensional model into finite element simulation software, setting temperature monitoring points at key nodes of each layer of the crimping type IGBT of the three-dimensionalmodel, setting boundary conditions in the finite element simulation software, and enabling the finite element simulation software to output maximum junction temperature, temperature information of thetemperature monitoring points and thermal power; when the difference value between the maximum junction temperature and the junction temperature measured according to the entity crimping type IGBT issmaller than a preset threshold value, calculating and obtaining a transient thermal impedance curve according to the temperature information and the thermal power; carrying out data fitting on the curve to obtain heat group parameters; and establishing the crimping type IGBT thermal network model. The technical problems that in the prior art, the IGBT thermal network model is established throughthe thermal group parameters of the data manual, so that the IGBT thermal network model cannot calculate the temperature distribution information of each layer of the IGBT, and the calculation precision is not high are solved.

The invention relates to an IGBT device power cycle evaluation method based on the application condition of an MMC converter valve, and belongs to the technical field of high-voltage direct current transmission. The method comprises the following steps: firstly, obtaining conduction loss and switching loss of a device based on a loss model of IGBT and a diode, and extracting average junction temperature and junction temperature fluctuation amplitude of the IGBT device and the diode according to a thermal network model of the IGBT device; secondly, considering the running condition of the MMC converter valve, providing a device failure rate calculation model, and acquiring the failure rate and the cycle times of the device; and finally, performing reliability evaluation modeling on the IGBTdevice based on a Miner rule and an equal damage rule, and acquiring a change rule of the reliability index of the IGBT device under different additional test conditions to form a reliability evaluation scheme. According to the invention, the IGBT device reliability evaluation method is formed, and has important significance for accurately evaluating the reliability of the IGBT device for the MMCconverter valve.