A maximum power point tracking method, comprising: configuring a voltage tuning direction of a power converter by a process circuit, such that an input voltage (Vdc) of the power converter changes in a trend that is one of a positive trend of the input voltage (Vdc) or a negative trend of the input voltage (Vdc); detecting the input voltage (Vdc) and an input current (Idc) of the power converter at a first time point to obtain a first power value; detecting the input voltage (Vdc) and the input current (Idc) of the power converter at a second time point after the first time point to obtain a second power value; detecting the input voltage (Vdc) and the input current (Idc) of the power converter at a third time point after the second time point to obtain a third power value; characterized by changing the voltage tuning direction of the power converter on the condition that the first power value is greater than the second power value, and the second power value is greater than the third power value, or on the condition that the first power value is smaller than the second power value, and the second power value is smaller than the third power value, such that the change of the input voltage (Vdc) switches from the positive trend to the negative trend, or from the negative trend to the positive trend, wherein the voltage tuning direction of the power converter remains unchanged on the condition that the first power value is greater than the second power value, and the second power value is smaller than the third power value, or on the condition that the first power value is smaller than the second power value, and the second power value is greater than the third power value; detecting the corresponding input voltage and input current of the power converter after the voltage tuning direction of the power converter is changed, to obtain a dynamic checking power value; and changing the voltage tuning direction of the power converter again on the condition that the dynamic checking power value is smaller than the third power value, wherein the voltage tuning direction of the power converter is not changed again on the condition that the dynamic checking power value is greater than the third power value. configuring a voltage tuning direction of a power converter by a process circuit, such that an input voltage (Vdc) of the power converter changes in a trend that is one of a positive trend of the input voltage (Vdc) or a negative trend of the input voltage (Vdc); detecting the input voltage (Vdc) and an input current (Idc) of the power converter at a first time point to obtain a first power value; detecting the input voltage (Vdc) and the input current (Idc) of the power converter at a second time point after the first time point to obtain a second power value; detecting the input voltage (Vdc) and the input current (Idc) of the power converter at a third time point after the second time point to obtain a third power value; characterized by changing the voltage tuning direction of the power converter on the condition that the first power value is greater than the second power value, and the second power value is greater than the third power value, or on the condition that the first power value is smaller than the second power value, and the second power value is smaller than the third power value, such that the change of the input voltage (Vdc) switches from the positive trend to the negative trend, or from the negative trend to the positive trend, wherein the voltage tuning direction of the power converter remains unchanged on the condition that the first power value is greater than the second power value, and the second power value is smaller than the third power value, or on the condition that the first power value is smaller than the second power value, and the second power value is greater than the third power value; detecting the corresponding input voltage and input current of the power converter after the voltage tuning direction of the power converter is changed, to obtain a dynamic checking power value; and changing the voltage tuning direction of the power converter again on the condition that the dynamic checking power value is smaller than the third power value, wherein the voltage tuning direction of the power converter is not changed again on the condition that the dynamic checking power value is greater than the third power value.