Nearest level pulse width modulation (NL-PWM) technology is an advanced modulation strategy that combines the nearest level modulation (NLM) and pulse width modulation (PWM) which can be used in cascaded H-bridge (CHB) converter, it has the advantages of low switching frequency and good harmonic characteristics. However, when the number of CHB sub-modules is small such as used in the medium-voltage distribution network, the THD of its output voltage is relatively high, and its switching point changes with the reference voltage which is not conducive to balancing control using the existing triangular carrier NL-PWM whereas the sawtooth carrier has a fixed transition point to facilitate voltage control. The harmonic characteristics of sawtooth carrier NL-PWM at different output voltage levels are analyzed through simulation, and its modulation performance is compared with the NL-PWM method based on the triangular carrier; Finally, CHB converter with 4 modules per H-bridge arm is built to verify the theoretical analysis based on the sawtooth carrier NL-PWM. The simulation and experimental results show that the THD of the output voltage and current of the proposed NL-PWM is significantly reduced than that of the triangular carrier one.