Switching control apparatus

A switching control apparatus

• applied to a load drive system that includes
• a DC voltage converter having a reactor that enables to store and release electric energy and at least one switching element connected to the reactor, and converting an input voltage, which is input from a DC power source to the reactor, to an output voltage by turning ON and OFF the at least one switching element, and
• a power transducer including a plurality of switching element pairs having a high potential switching element and a low potential switching element, turning ON and OFF the plurality of switching element pairs, converting DC power, which is output from the DC voltage converter, to AC power, and outputting the AC power to a load, and
• controlling a switching timing of the switching element in the DC voltage converter and the switching element pairs in the power transducer, the switching control apparatus comprising:
• a DC voltage converter control circuit calculating control amount of the DC voltage converter according to a command voltage to the output voltage of the DC voltage converter;
• a DC voltage converter drive circuit driving the switching element in the DC voltage converter according to the control amount of the DC voltage converter calculated by the DC voltage converter control circuit;
• a power transducer control circuit calculating control amount of the power transducer according to a required output that the load requests;
• a power transducer drive circuit driving the switching element pairs in the power transducer according to the control amount of the power transducer calculated by the power transducer control circuit;
• a switching prohibition period calculation portion calculating a switching prohibition period, wherein the switching prohibition period corresponds to
• a period when the switching element in the DC voltage converter is prohibited from switching for a predetermined period synchronized with a first certain switching timing before the first certain switching timing of at least one of the switching element pairs in the power transducer, or
• a period when the switching element pairs in the power transducer are prohibited from switching for a predetermined period synchronized with a second certain switching timing before the second certain switching timing of the at least one switching element in the DC voltage converter;
• and
• a switching correction portion determining a correction direction of a correction object switching timing and correcting the correction object switching timing to the correction direction, wherein
• when the first certain switching timing of the at least one of the switching element pairs in the power transducer or the second certain switching timing of the at least one switching element in the DC voltage converter is predicted to be in the switching prohibition period, the first certain switching timing or the second certain switching timing correspond to the correction object switching timing,
• the switching correction portion determines a correction direction of the correction object switching timing and determines whether the correction object switching timing is advanced to an initiation timing of the switching prohibition period or the correction object switching timing is delayed to an end timing of the switching prohibition period,
• when the switching correction portion determines the correction direction, the switching correction portion corrects the correction object switching timing to the determined correction direction.