The Low Energy High Intensity Proton Accelerator (LEHIPA), being developed at the Bhabha Atomic Research Centre (BARC) will produce a 20MeV, 30mA, continuous wave(CW) proton beam. At these low velocities, space-charge forces dominate, and could lead to larger beam sizes and beam halos. Hence in the design of the focusing lattice of the LEHIPA drift tube linac (DTL) using permanent magnet quadrupoles(PMQs), a larger good field region is preferred. Here we study, using the two dimensional (2D) and three dimensional (3D) simulation codes PANDIRA and RADIA, four different types of cylindrical PMQ designs :16-segment trapezooidal Halbach configuration, bullet-nose dgeometry and 8-and 16- segment rectangular geometries. The trapezoidal Halbach geometry is used in a variety of accelerators since it provides very high field gradients in small bores, while the bullet-nose dgeometry, which is a combination of the trapezoidal and rectangular designs, is used insome DTLs. This study shows that a larger good field region is possible in the16-segment rectangular design as compared to the Halbach and bullet-nosed designs, making it more attractive for high-intensity proton linacs. An improvement in good-field regionby ∼16% overthe Halbach design is obtained in the optimized 16-segment rectangular design, al though the field gradient is lower by ∼20%.  Tolerance studies show that the rectangular segment PMQ design is substantially less sensitive to the easy axis orientation errors and hence will be a better choice for DTLs.