Electric heater apparatus for electric vehicle and method of controlling same

An electric heater apparatus for an electric vehicle comprising:

• a power supply part;
• a switch control part configured to generate a switching control signal according to a control command of an air-conditioner controlling part;
• a switching part switched according to the switching control signal of the switch control part, the switching part configured to supply electric power of the power supply part to a PTC heater;
• and
• the PTC heater configured to receive the electric power of the switching part and to generate heat,
• wherein the switching part includes a plurality of switching modules set to control an output load of the PTC heater,
• wherein the switch control part is configured to operate the plurality of switching modules in a particular order according to a target heating temperature, the particular order consisting of a serial order,
• wherein the plurality of switching modules comprise IGBTs (Insulated Gate Bipolar mode Transistors) which are high-voltage switching elements, each IGBT with the same maximum allowable current capacity,
• wherein the switch control part divides a temperature control section of the heating part according to the number of the IGBTs,
• wherein the switch control part carries out a duty control of one IGBT in the case that temperature control is carried out by electric current which does not exceed the maximum allowable current capacity of one IGBT, and carries out the duty control of one IGBT and controls other IGBTs to maintain a full-on operation state in the case that the temperature control is carried out by electric current which is in an allowable current capacity range of two or more IGBTs, and
• wherein the switch control part turns off the IGBT which is in the duty control and carries out the duty control of one of the IGBTs which are in the full-on operation state so as to reduce the temperature, in the case that the IGBT which is in the duty control reaches the minimum duty control value of the IGBT during a temperature decrease control.