This paper presents an analytical model of U-shape tooth-coil-winding modular permanent magnet synchronous machines (TCW-MPMSMs) in terms of main design parameters. Analytical expressions for the flux density distribution, back EMF, and electromagnetic torque were derived. 2-D finite element (FE) simulations for a 24-slot 28-pole machine for several tooth tip widths were compared to validate the proposed equations. Comparison of analytical solutions and FE results showed good agreement for a range of feasible slot openings. Also, a sensitivity analysis through the analytical expressions was developed. By using proposed analytical models, the performance of the modular machine can be significantly improved by selecting optimum values of key parameters including the dimensions of tooth tips and PMs.