Inverter control device

An inverter control device controlling an inverter by selecting a switching vector to be supplied to the inverter so that a detection current flowing in a coil winding of each phase of an electric motor follows a specified current value, the inverter control device comprising:

• current deviation detection means configured to detect a current flowing in a coil winding of each phase of the electric motor driven by the inverter, and to obtain a deviation between the current detection value detected and a specified current value that is given in advance per each phase;
• switching vector determination means configured to determine the switching vector every a given timing in order to decrease the deviation of each phase obtained by the current deviation detection means;
• selection means configured to select the switching vector determined by the switching vector determination means until the elapse of a keeping time that is given in advance from the time at which the switching vector determination means determined the switching vector, and to selects a zero switching vector by which a voltage difference between each pair of the phases becomes zero until a time at which the switching vector determination means selects a new switching vector after the elapse of the keeping time;
• and
• inverter driving means configured to drive the inverter based on the switching vector selected by the selection means.

An inverter control device controlling an inverter by selecting a switching vector to be supplied to the inverter so that a detection current flowing in a coil winding of each phase of an electric motor follows a specified current value, the inverter control device comprising:

• current deviation detection means configured to detect a current flowing in a coil winding of each phase of the electric motor to be driven by the inverter, and obtain a deviation between the current detection value and a specified current value that is given in advance per each phase;
• switching vector determination means configured to determine the switching vector in order to decrease the deviation of each phase obtained by the current deviation detection means;
• selection means configured to select the switching vector determined by the switching vector determination means while a zero vector selection condition is not satisfied and to selects a zero switching vector by which a voltage difference between each pair of the phases becomes zero while the zero vector selection condition is satisfied;
• and
• inverter driving means configured to drive the inverter based on the switching vector selected by the selection means,
• wherein the current deviation detection means comprises:
• first comparison means;
• and second comparison means, in which
• the first comparison means is configured to output the a first medium level, a large level, and a small level as the deviation between the current detection value and the specified current value of each phase,
• the first medium level indicates that an absolute value of the deviation is smaller than a first specified value set in advance,
• the large level indicates that the current detection value is not less than the first specified value larger than the current instruction value, and
• the small level indicates that the current detection value is not more than the first specified value smaller than the current instruction value, and the second comparison means is configured to output a second medium level and non-second medium level for each phase, in which
• the second medium level indicating that the absolute value of the deviation is smaller than the second specified value that is smaller than the first specified value, and
• the selection means determines that the zero vector selection condition is satisfied until the time at which the deviation of at least one phase is changed to another level other than the first medium level after the deviation of at least one phase is changed from the second medium level to another level other than the second medium level under the condition in which the current deviation detection means detects that the deviations of all of the phases are the first medium level.