Single-stage alternating current to direct current converter

Disclosed is a single-stage alternating current to direct current converter. The single-stage alternating current to direct current converter comprises a bus capacitor, a power factor correction module, a resonance conversion module and a control module, wherein the power factor correction module generates a bus voltage which crosses the bus capacitor and is direct current through an alternating current input voltage, a first control signal and a second control signal, and generates an intermediate voltage which is switched between the bus voltage and zero; the resonance conversion module generates a direct current output voltage according to the intermediate voltage; the control module generates the first control signal and the second control signal according to the bus voltage; and each of the first control signal and the second control signal is switched between an effective state and a non-effective state, and the duty cycle of the first control signal to the second control signal is associated to the bus