Five-level topology units and inverters based on the five-level inverter units without a boost circuit. Cost is reduced by using only one AC filtering inductor and high efficiency is achieved in the absence of an extra boosting circuit. Leakage current is eliminated substantially by using a half-bridge inverter module. A five-level inverter including a five-level topology unit without a boost circuit to raise the input voltage is able to output the same AC power as a five-level full bridge inverter under the same working condition.