[信息與通信]第二部分頂驅(qū)內(nèi)外部接線plc變頻張光勇(完整版)
【正文】 oltage is removed, the IGBT will turn OFF, during the OFF state a Negative voltage is applied (typically 15VDC) to prevent the device from turning ON. Current Flow 15 VD Variable Frequency Drive ?Insulated Gate Bipolar Transistor Mounting Bolts Holes (6) for mounting IGBT to Heat Sink Gate Collector Emitter Variable Frequency Drive IVI Board IGBT’s On Heatsink 4 Off Each Phase (12 Total) CUVC Card IGD8 Board Fibre Optic Connections Power Connections Fibre Optic Cables Drive HeatSink Variable Frequency Drive ?Developing a basic AC Output ?Switches replace the IGBT’s ?A voltage that alternates between positive and negative is developed by opening and closing switches in a specific sequence Variable Frequency Drive ?During Step 1 and Step 2 A+ and B are Closed, the AB Output voltage is Positive ?During Step 3 A+ and B+ are Closed, the AB Output voltage is Zero ?During Step 4 A and B+ are Closed, the AB Output voltage is Negative ?The Voltage is dependant on the value of the DC Voltage ?The Frequency is dependant on the speed of the Switching Adding Sine Wave, shows how AC Output is Simulated Variable Frequency Drive ?Generating a PWM Output ?The IGBT switched on progressively Longer, allowing current to Build Up in the motor to a peak ?The IGBT then switched on progressively Shorter, allowing current in the motor to Decrease Variable Frequency Drive ?The Voltage and Frequency is controlled electronically by circuitry within the AC Drive ?The fixed DC Bus Voltage of 780 VDC is modulated or clipped with this method to provide a Variable Voltage and Variable Frequency Output 780 VDC ?
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