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IGBT的最佳开关时间
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作者 梁锐 贺伟衡 邓天军 《河南科技》 2014年第3X期96-97,共2页
IGBT的门是绝缘结构,和MOSFET一样通过门电压可以控制ON、OFF。开关太快的话,逆恢复电流增大,损失增加;太慢的话,开关上需要时间,损失增加,因此,研讨最佳开关时间,让开关速度(dIc/dt)和电流、开关时间的关系明确化。结果是开关速度定为... IGBT的门是绝缘结构,和MOSFET一样通过门电压可以控制ON、OFF。开关太快的话,逆恢复电流增大,损失增加;太慢的话,开关上需要时间,损失增加,因此,研讨最佳开关时间,让开关速度(dIc/dt)和电流、开关时间的关系明确化。结果是开关速度定为和负荷电流与逆恢复时间Trr1的比相同的话,很明确得出On时的最小开关损失。 展开更多
关键词 IGBT MOSFET dVce/dt dIc/dt Trr 开关损失
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Numerical Simulation on a Throttle Governing System with Hydraulic Butterfly Valves in a Marine Environment 被引量:2
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作者 万会雄 方俊 黄辉 《Journal of Marine Science and Application》 2010年第4期403-409,共7页
Hydraulic butterfly valves have been widely applied in marine engineering because of their large switching torque, low pressure loss and suitability for large and medium diameter pipelines. Due to control problems res... Hydraulic butterfly valves have been widely applied in marine engineering because of their large switching torque, low pressure loss and suitability for large and medium diameter pipelines. Due to control problems resulting from switching angular speeds of the hydraulic butterfly valve, a throttle-governing control mode has been widely adopted, and detailed analysis has been carried out worldwide on the structural principle concerning speed-regulation and the load torque on the shaft while opening or closing a hydraulic butterfly valve. However relevant reports have yet been published on the change law, the error and the influencing factors of the rotational angular velocity of the hydraulic butterfly valve while opening and closing. In this article, research was based on some common specifications of a hydraulic butterfly valve with a symmetrical valve flap existing in a marine environment. The throttle governing system supplied by the accumulator to achieve the switching of the hydraulic control valve was adopted, and the mathematical models of the system were established in the actual conditions while the numerical simulations took place. The simulation results and analysis show that the rotational angular velocity and the error of the hydraulic butterfly valve while switching is influenced greatly by the drainage amount of the accumulator, resulting in pressure loss in the pipeline, the temperature of hydraulic medium and the load of the hydraulic butterfly valve. The simulation results and analysis provide a theoretical basis for the choice of the total capacity of the accumulator and pipeline diameters in a throttle governing system with a hydraulic butterfly valve.It also determines the type and specification of the hydraulic butterfly valve and the design of motion parameters of the transported fluid. 展开更多
关键词 hydraulic butterfly valve throttle governing switching angular speed load characteristics numerical simulation
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