A load controller includes a casing; a busbar module, the busbar module including a DC busbar and an AC busbar connected to a load; a capacitor connected to an external DC power supply, the capacitor being connected to the DC busbar; an IGBT power module, an input end of each IGBT being connected to the DC busbar, and an output end of each IGBT being connected to the AC busbar; a heat-dissipating module, the heat-dissipating module including multiple heat-dissipating fins, each IGBT in a same column of IGBTs being sandwiched between adjacent two heat-dissipating fins; a driving circuit board, the driving circuit board being electrically connected to each IGBT; and a control circuit board, the control circuit board being connected to the driving circuit board, where all of the busbar module, the IGBT power module, the heat-dissipating module, the driving circuit board and the control circuit board are disposed on the casing.