Ac-dc photovoltaic device

An alternating-current direct-current (AC-DC) photovoltaic device, comprising:

• a photovoltaic module,
• a direct current side capacitor,
• a direct current pulse width modulation (DC-PWM) power switching circuit, and
• a controller, wherein
• the direct current side capacitor is connected in parallel with an output terminal of the photovoltaic module;
• an input terminal of the DC-PWM power switching circuit is connected with the output terminal of the photovoltaic module;
• the DC-PWM power switching circuit comprises a controllable switch transistor;
• the controller is configured to output a switch control signal to control a switching state of the controllable switch transistor in the DC-PWM power switching circuit, to control the DC-PWM power switching circuit to output a direct current PWM wave in a case that the switch control signal is a direct current modulation signal and output an alternating current PWM wave in a case that the switch control signal is an alternating current modulation signal.