Multiple-frequency inversion method and control apparatus for internal combustion engine driven generator

A multiple-frequency inversion method for an internal combustion engine driven generator, wherein it comprises:

• rectifying the output voltage of a filter unit;
• after performing analog-to-digital conversion for the rectified output voltage, calculating the average value of the output voltage or the effective value of the output voltage;
• comparing the average value of the output voltage with a target voltage value or comparing the effective value of the output voltage with a target voltage value;
• according to the comparison results, adjusting the proportionality coefficient of two sine with a 180-degree phase difference in a table of sine until the average value or the effective value of the output voltage falls within a preset range of the target voltage value;
• the table of sine is used for generating two sine waves with a 180-degree phase difference, and the two sine waves with a 180-degree phase difference are compared with a triangle wave to generate four PWM waves which have pulse frequency f, and the triangle wave has a frequency f;
• the four PWM waves which have frequency f drive switching tubes in an inverter unit to enable the inverter unit to output modulated wave with a pulse frequency 2f.

A control apparatus for an internal combustion engine driven generator, configured to control the internal combustion engine driven generator, wherein the internal combustion engine, which functions as a prime motor, drives the generator to generate electricity, and an alternating current outputted by the generator is rectified into a direct current by a rectifying unit, and the direct current is outputted to an inverter unit subsequently;

• controlled by a controller, the inverter unit inverts the direct current into a required alternating current which is provided to a load after being filtered by a filter unit;
• the controller controls the opening degree of the throttle of the internal combustion engine through a throttle controller so as to control the output current;
• the controller controls the states of switching tubes of the inverter unit through PWM wave, wherein the apparatus comprises:
• an output voltage calculating unit configured to rectify the output voltage of the filter unit over again, after performing analog-to-digital conversion for the rectified output voltage, calculate the average value or the effective value of the output voltage;
• a comparing unit configured to compare the average value of the output voltage with a target value thereof or compare the effective value of the output voltage with a target value thereof;
• a control unit configured to, according to the comparison results, adjust the proportionality coefficient of two sine with a 180-degree phase difference in a table of sine until the average value or the effective value of the output voltage falls within a preset range of the target voltage value;
• the table of sine is used for generating two sine waves with a 180-degree phase difference, and the two sine waves with a 180-degree phase difference are compared with a triangle wave to generate four PWM waves which have pulse frequency f, and the triangle wave has a frequency f;
• the four PWM waves which have frequency f drive switching tubes in an inverter unit to enable the inverter unit to output modulated wave with a pulse frequency 2f.

A control method for an internal combustion engine driven generator, wherein, the internal combustion engine, which functions as a prime motor, drives the generator to generate electricity, and an alternating current outputted by the generator is rectified into a direct current by a rectifying unit, and the direct current is outputted to an inverter unit subsequently;

• controlled by a controller, the inverter unit inverts the direct current into a required alternating current which is provided to a load after being filtered by a filter unit;
• the controller controls the opening degree of the throttle of the internal combustion engine through a throttle controller so as to control the output current;
• the controller controls the states of switching tubes of the inverter unit through PWM wave, wherein the method further comprises:
• rectifying the output voltage of the filter unit over again, after performing analog-to-digital conversion for the rectified output voltage, calculating the average value or the effective value of the output voltage;
• comparing the average value of the output voltage with a target value thereof or comparing the effective value of the output voltage with a target voltage value thereof;
• according to the comparison results, adjusting the proportionality coefficient of two sine with a 180-degree phase difference in a table of sine until the average value or the effective value of the output voltage falls within a preset range of the target voltage value;
• the table of sine is used for generating two sine waves with a 180-degree phase difference, and the two sine waves with a 180-degree phase difference are compared with a triangle wave to generate four PWM waves which have pulse frequency f, and the triangle wave has a frequency f;
• the four PWM waves which have frequency f drive switching tubes in an inverter unit to enable the inverter unit to output modulated wave with a pulse frequency 2f.