DC conversion system and control method thereof

A DC conversion system, comprising:

• an input terminal and an output terminal;
• an upper power module group comprising an input terminal, an output terminal, and at least two first power modules, the input terminals of the at least two first power modules being connected in series, and the output terminals of the at least two first power modules being connected in parallel;
• a lower power module group comprising an input terminal, an output terminal, and at least two second power modules, the input terminals of the at least two second power modules being connected in series, and the output terminals of the at least two second power modules being connected in parallel;
• the input terminal of the upper power module group and the input terminal of the lower power module group being connected in series, and the output terminal of the upper power module group and the output terminal of the lower power module group being connected in parallel;
• a controller coupled to the upper power module group and the lower power module group, and the controller is configured to:
• receive an input voltage of respective input terminal of each of the first power modules and the second power modules;
• a current of the output terminal of the upper power module group defining a first output current, a current of the output terminal of the lower power module group defining a second output current, a current of the output terminal of the DC conversion system defining a total output current, receive at least two of the first output current, the second output current, and the total output current;
• and
• generate a modulation signal according to at least two of the first output current, the second output current, and the total output current, as well as the input voltage of each of the first power modules and the second power modules, so as to control a power switch of each of the first power modules and the second power modules,
• wherein the controller comprises a main controller and a plurality of local controllers,
• the main controller being coupled with the plurality of local controllers, and the main controller is configured to:
• generate a ninth control signal according to the first output current and a first output reference current and generate a tenth control signal according to the second output current and a second output reference current;
• each of the plurality of local controllers being coupled to a corresponding one of the first power modules and the second power modules, wherein, each of the plurality of local controllers coupled to the first power modules is configured to:
• receive the ninth control signal;
• receive the respective input voltage, and generate a corresponding third control signal according to the respective input voltage and a first input reference voltage;
• and
• generate a corresponding first modulation signal according to the ninth control signal and the third control signal, so as to control the power switch of the respective first power module;
• wherein, each of the plurality of local controllers coupled to the second power modules is configured to:
• receive the tenth control signal;
• receive the respective input voltage and generate a corresponding fourth control signal according to the respective input voltage and a second input reference voltage;
• and
• generate a corresponding second modulation signal according to the tenth control signal and the fourth control signal, so as to control the power switch of the respective second power module.

A control method for a DC conversion system, wherein the DC conversion system comprises at least two first power modules, at least two second power modules, and a controller, and input terminals of the at least two first power modules being connected in series to form an upper power module group, input terminals of the at least two second power modules being connected in series to form a lower power module group, and output terminals of each of the first power modules and each of the second power modules being connected in parallel, the controller being coupled to each of the first power modules and the second power modules, and the control method comprising:

• acquiring a respective input voltage of each of the first power modules and the second power modules;
• acquiring a first output current of the upper power module group, a second output current of the lower power module group, and a total output signal of the output terminal of the DC conversion system;
• generating a modulation signal according to the input voltage of each of the first power modules and the second power modules, the first output current, the second output current, and the total output signal;
• according to the modulation signal, controlling a power switch of each of the first power modules and the second power modules,
• wherein the step of generating the modulation signal according to the input voltage, the first output current, the second output current, and the total output signal comprising:
• generating a fifth control signal according to the total output signal and a total output reference signal;
• generating a sixth control signal according to the first output current and a first output reference current;
• generating a corresponding third control signal according to the respective input voltage of each of the first power modules and a first input reference voltage;
• generating a corresponding first modulation signal according to the fifth control signal, the sixth control signal, and the third control signal, and according to the first modulation signal, controlling the power switch of the respective first power module;
• and
• generating a seventh control signal according to the total output signal and a total output reference signal;
• generating an eighth control signal according to the second output current and a second output reference current;
• generating a corresponding fourth control signal according to the respective input voltage of each of the second power modules and a second input reference voltage;
• generating a corresponding second modulation signal according to the seventh control signal, the eighth control signal, and the fourth control signal, and according to the second modulation signal, controlling the power switch of the respective second power module.