At present,the velocity measuring method of high-speed object commonly used sensors.Since the delay of sensors is the range of microsecond,traditional velocity measuring method with big error does not reach application requirements when the measured object moves rapidly.This paper introduces a velocity measuring design of high-speed object based on FPGA,which avoids to use sensors and makes the overall error decrease to about 0.00828%.The design of velocity measurement system,based on Quartus Ⅱ as software platform,uses modular design to display the final results dynamically through the digital drive circuit.Advantages of the system are high accuracy,less peripheral circuit,high integration and high reliability etc.

This paper presents the design process and test results of a high-temperature superconducting pulsed-power transformer (HTSPPT). The primary winding of the HTSPPT is constructed out of several double-pancake-type coils connected in series. Every double-pancake-type coil is made of Bi2223/Ag tapes. The secondary winding is constructed out of several single-pancake-type coils made of normal conductors. The configuration of the HTSPPT is designed such that the primary and secondary coils are arranged in interleaving. The testing experiments show that a high-current impulse could be achieved with a small current in the primary, which proves that the designed test circuit and the configuration of HTSPPT are feasible.

The feasibility of IGBT series-connected power switching circuit is presented, The lower voltage-lever IGBTs with the help of a simple and reliable auxiliary circuit can quickly meet the voltage level requirements in the hard-switching applications. The performances of single CM600HA-24H(600 A/1 200 V)IGBT and two CM600HA-12H(600 A/600 V)IGBTs series-connected are analysed respectively with the help of the simulation software OrCAD/PSpice. The significant simulation prove theoretically that IGBT series-connected has much higher performance in the energy loss, the collector over-voltage and the switching frequency than single IGBT, which provides a guiding significance on the practice.

The serial use of the Insulated Gate Bipolar transistor(IGBT) provides a shortcut method to improve withstand voltage capability.The dynamic voltage sharing must be resolved when IGBT as the main circuit-breaker of inductance stored energy pulse power system.In engineering applications,the uneven gate drive signals of the series IGBTs are the most important factor leading to the dynamic voltage sharing at IGBTs switching moment.This paper respectively analyzes and validates the compensation effect of load's passive voltage sharing and grid's initiative voltage sharing.The results show that both two methods can achieve a good effect of dynamic voltage sharing.On this basis,the series application of multiple IGBTs modules has been proposed by the means of resistance and capacitance diode.The simulation validates the feasibility of series application of three IGBTs in this way.It will do a great significance on engineering applications.

In order to effectively improve the output current by means of pulse transformer model,this paper introduced a method for the hybrid application through importing superconducting technology based on normal pulse transformers.Through theoretical analysis and parameter calculation,a high temperature superconducting hybrid pulse transformer,which consists of three superconducting double pancake type windings and two single pancake type copper windings,was developed for the experiment.The pulse discharge test with this transformer was done.The experiment results show that the output current reaches 2.6kA when input voltage of charging capacitor is 610V,with a current ratio of 1:30.The test results match the designed results.

Rigorous timing was required in some occasion such as induction adder pulse genetator and a kind of basic model of high voltage large power IGBT based on FPGA for controlling IGBT effectively was analyzed.Integrated driver chip 2SD315AL-33 was used in driving IGBT and TLP521-2 was used in electrical isolation,the trigger signal generated by FPGA and the control process could be modified according to the actual condition.At last the outline for practical IGBT driver was provided.The experimental results show that the design meets actual requirements and the trigger achieves high stability and high precision.