The Pohang Accelerator Laboratory (PAL) had started the upgrade project (called PLS-II) of the Pohang Light Source (PLS) from 2009 for increasing its energy from 2.5 GeV to 3 GeV and changing the operation mode from fill-up to top-up mode. Top-up mode operation requires high energy stability from the linac beam energy and machine reliability of the linac modulator systems. For providing an additional 0.5 GeV energy to the 2.5 GeV PLS linac, we added four units of the modulator system. We have two different types of the pulse modulator system in the upgrade project (PLS-II). They are thyristor control type and inverter power type. In the thyristor control type, PAL employs a de-Qing system to regulate the PFN charge voltage and controls the modulator pulse forming network (PFN) charging voltage stability. In the inverter power supply type, Capacitor Charging Power Supply (CCPS) provides highly stable charging voltage to the modulator. We will present development and management of the pulse modulator system for obtaining machine reliability and stability from 3.0 GeV linac.