This paper considers the limit cycle bifurcation problem of planar piecewise differential systems with three zones. Some computation formulas studied the problem of limit cycle bifurcations are provided by introducing multiple parameters. As an application to the obtained method, the number of limit cycles of a piecewise linear system with three zones studied in Lima et al. (2017) is discussed and some more limit cycles are found.

中文翻译：

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具有三个区域的平面分段微分系统的极限环分支

本文考虑了具有三个区域的平面分段微分系统的极限环分支问题。通过引入多个参数，提供了一些研究极限环分支问题的计算公式。作为获得的方法的应用，在Lima等人中研究了具有三个区域的分段线性系统的极限环数。（2017）进行了讨论，并找到了更多的极限周期。