A method for synchronizing PWM control signals of inverters, wherein a direct current voltage terminal of an inverter circuit of the inverter is connected to an external direct current power supply, an alternating current voltage terminal of the inverter circuit of the inverter is connected to an alternating current point of common coupling of a power grid, and the method comprises: obtaining a phase of an alternating current voltage of the power grid, wherein a length of an effective interval of the phase of the alternating current voltage is 2π, and the phase is a value in [-π, π) or [0, 2π); determining a time period during which the phase of the alternating current voltage varies within a preset phase threshold interval, when it is detected that the phase of the alternating current voltage has reached a phase threshold, wherein the phase threshold is a start phase of the preset phase threshold interval; calculating a period of a preset carrier wave based on a preset carrier wave ratio and the time period; generating the preset carrier wave based on the period of the preset carrier wave; and generating a PWM control signal of the inverter based on a PWM modulation signal and the preset carrier wave, so that the inverter circuit of the inverter converts a direct current voltage of the external direct current power supply into the alternating current voltage of the power grid based on the PWM control signal; wherein the obtaining the phase of the alternating current voltage of the power grid comprises: phase-locking the alternating current voltage of the power grid to obtain a phase waveform of the alternating current voltage of the power grid; and obtaining the phase of the alternating current voltage from the phase waveform; wherein the phase-locking the alternating current voltage of the power grid to obtain the phase waveform of the power grid voltage comprises: phase-locking the power grid voltage by using a predetermined phase-lock algorithm, to obtain the phase waveform of the power grid voltage, wherein the predetermined phase-lock algorithm comprises at least any one of the following: a single synchronous reference frame software phase-locked loop, a single synchronous reference frame software phase-locked loop with a method of symmetrical components, a decoupled double synchronous reference frame software phase-locked loop, and a software phase-locked loop based on a double second-order generalized integrator. obtaining a phase of an alternating current voltage of the power grid, wherein a length of an effective interval of the phase of the alternating current voltage is 2π, and the phase is a value in [-π, π) or [0, 2π); determining a time period during which the phase of the alternating current voltage varies within a preset phase threshold interval, when it is detected that the phase of the alternating current voltage has reached a phase threshold, wherein the phase threshold is a start phase of the preset phase threshold interval; calculating a period of a preset carrier wave based on a preset carrier wave ratio and the time period; generating the preset carrier wave based on the period of the preset carrier wave; and generating a PWM control signal of the inverter based on a PWM modulation signal and the preset carrier wave, so that the inverter circuit of the inverter converts a direct current voltage of the external direct current power supply into the alternating current voltage of the power grid based on the PWM control signal; wherein the obtaining the phase of the alternating current voltage of the power grid comprises: phase-locking the alternating current voltage of the power grid to obtain a phase waveform of the alternating current voltage of the power grid; and obtaining the phase of the alternating current voltage from the phase waveform; wherein the phase-locking the alternating current voltage of the power grid to obtain the phase waveform of the power grid voltage comprises: phase-locking the power grid voltage by using a predetermined phase-lock algorithm, to obtain the phase waveform of the power grid voltage, wherein the predetermined phase-lock algorithm comprises at least any one of the following: a single synchronous reference frame software phase-locked loop, a single synchronous reference frame software phase-locked loop with a method of symmetrical components, a decoupled double synchronous reference frame software phase-locked loop, and a software phase-locked loop based on a double second-order generalized integrator.