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Frontiers of Information Technology & Electronic Engineering
ISSN 2095-9184 (print), ISSN 2095-9230 (online)
2015 Vol.16 No.12 P.1088-1098
A driving pulse edge modulation technique and its complex programming logic devices implementation
Abstract: With the continual increase in switching speed and rating of power semiconductors, the switching voltage spike becomes a serious problem. This paper describes a new technique of driving pulse edge modulation for insulated gate bipolar transistors (IGBTs). By modulating the density and width of the pulse trains, without regulating the hardware circuit, the slope of the gate driving voltage is controlled to change the switching speed. This technique is used in the driving circuit based on complex programmable logic devices (CPLDs), and the switching voltage spike of IGBTs can be restrained through software, which is easier and more flexible to adjust. Experimental results demonstrate the effectiveness and practicability of the proposed method.
Key words: Driving pulse edge modulation, Switching voltage spike, Complex programmable logic device (CPLD), Active gate drive
创新点：利用面积等效原理，将门极驱动脉冲信号的边沿映射成一簇脉冲序列，门极驱动电压的上升或下降段即为这些脉冲信号响应的叠加。通过调节脉冲序列的密度和脉冲宽度，调节门极驱动电压边沿斜率，从而调节开关速度限制开关电压尖峰。
方法：将传统的门极驱动信号的边沿映射成一簇脉冲序列，将PWM信号转换为MPWM信号，则脉冲边沿的调制也即为调制该脉冲序列的密度和脉冲宽度，有双向脉冲序列调制BPTM和单向脉冲序列调制UPTM两种方法。对于BPTM调试，MPWM信号为正表示正的驱动电压vge,on被接入，MPWM信号为负则表示负的驱动电压vge,off被接入。在IGBT开通时期，若驱动电路的响应能力有限，这种调试方法下门极驱动电压的边沿呈现明显锯齿状，使得门极电压在IGBT导通阈值电压vge,th附近波动，引起IGBT的伪导通，故而可改进为UPTM方法。对于UPTM调制，当调试上升沿时，高电平信号表示接入正的驱动电压vge,on，低电平信号表示不接入驱动电压从而保持门极电压为当前值；当调试下降沿时，高电平信号表示接入负的驱动电压vge,off，低电平信号表示不接入驱动电压从而保持门极电压为当前值。文中图9是采用CPLD的具体驱动电路，在BPTM模式下，MOSFET1管和MOSFET2管交替开通和关断，以调制驱动脉冲边沿；在UPTM模式下，只有一个MOSFET管开通和关断来调制驱动脉冲边沿，而另一个MOSFET管被封锁。
结论：采用驱动脉冲边沿调制技术（双向脉冲序列调制BPTM和单向脉冲序列调制UPTM），可以明显抑制开关尖峰。由于基于数字技术，且只需要一个数字芯片，不需要改变硬件电路结构，可通过软件来实现对驱动脉冲边沿的调控，使其适用于不同工况，具有较强的通用性和灵活性。其中，采用单向脉冲序列调制（UPTM）可以解决IGBT伪导通问题，该调制技术对驱动电路响应速度要求不高的特点使其更便于应用。
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DOI:
10.1631/FITEE.1500111
CLC number:
TN303
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On-line Access:
2015-12-07
Received:
2015-04-07
Revision Accepted:
2015-06-25
Crosschecked:
2015-11-06