Voltage converter control apparatus, and method

A voltage conversion device having a structure in which an upper switching element and a lower switching element are serially connected and a reactor for temporarily storing energy based on a current from a power source is connected to a connection point of the both switching elements, for converting a voltage of the power source, which is input while utilizing the reactor, into a desired voltage through switching of the switching elements, the voltage conversion device, comprising:

• a condition detection circuit for detecting an electromotive voltage of the power source and a voltage on an output side of the voltage conversion device as a condition of the power source;
• and
• a control circuit for setting a ratio range based on output characteristics of the power source corresponding to the detected condition of the power source, the ratio range being a range of ratios each between a period with the upper switching element remaining in an ON state and a period with the lower switching element remaining in an ON state, and for controlling the ratio between the periods with the respective switching elements remaining in an ON state so as to remain within the set ratio range,
• wherein
• the power source is chargeable and dischargeable, and,
• an output obtained through conversion into the desired voltage is supplied to a load.

A voltage conversion device having a reactor for temporarily storing energy based on a current from a power source, for converting a voltage of the power source, which is input while utilizing the reactor, into a desired voltage through switching of a switching element to output, comprising:

• a voltage detection circuit for detecting a voltage of the power source;
• and
• a control circuit for applying switching control to the switching element such that the detected voltage remains within a predetermined range which is determined based on the electromotive voltage of the power source,
• wherein
• the power source is chargeable and dischargeable,
• an output obtained through conversion into the desired voltage is supplied to a load, and
• the predetermined range is a range a lower limit of which is a half of the electromotive voltage of the power source.

A voltage conversion device for converting a voltage of a power source into a desired output voltage, comprising:

• a reactor having one end connected to one end of the power source;
• a switching circuit having a first switching element positioned between other end of the reactor and an output terminal and a second switching element positioned between the other end of the reactor and other end of the power source;
• and
• a control circuit for controlling switching of the first and second switching elements of the switching circuit,
• wherein
• the power source is chargeable and dischargeable,
• the desired output voltage is supplied to a load, and
• the control circuit limits a ratio between periods with the first and second switching elements remaining in an ON state such that the ratio remains in a predetermined range, based on permissible current capacities of the first and second switching element by controlling such that a proportion of a period with either one of the first and second switching elements remaining in an ON state, relative to combined periods with the first and second switching elements relatively remaining in an ON state remains equal to or smaller than (Vbo−Rb×Ibmax)/Vc, Vbo representing an output voltage of the power source, Rb representing inner resistance of the power source, Ibmax representing a permissible current capacity of the switching element, and Vc representing the output voltage.

A voltage conversion device for converting a voltage of a power source into a desired output voltage, comprising:

• a reactor having one end connected to one end of the power source;
• a switching circuit having a first switching element positioned between other end of the reactor and an output terminal and a second switching element positioned between the other end of the reactor and other end of the power source;
• a control circuit for controlling switching of the first and second switching elements of the switching circuit;
• and
• a current detector for detecting a current flowing through the first or second switching element,
• wherein
• the power source is chargeable and dischargeable,
• the desired output voltage is supplied to a load, and
• the control circuit limits a ratio between periods with the first and second switching elements remaining in an ON state based on the detected current value such that the ratio remains in a predetermined range by controlling such that a proportion of a period with either one of the first and second switching elements remaining in an ON state, relative to combined periods with the first and second switching elements relatively remaining in an ON state remains equal to or smaller than (Vbo−Rb×Ibmax)/Vc, Vbo representing an output voltage of the power source, Rb representing inner resistance of the power source, Ibmax representing a maximum value of a current of the power source, and Vc representing the output voltage.

A voltage conversion method for converting a voltage of a power source, which is input while utilizing a reactor for temporarily storing energy based on a current from the power source, into a desired voltage through switching of a switching element to output, comprising:

• detection of an electromotive voltage and inner resistance of the power source as a condition of the power source;
• setting a current range of the power source based on output characteristic of the power source corresponding to the detected condition of the power source;
• and
• applying switching control to the switch element such that the current of the power source remains within the set current range,
• wherein
• the power source is chargeable and dischargeable, and,
• an output obtained through conversion into the desired voltage is supplied to a load.

A method for converting a voltage of a power source utilizing a voltage conversion device having a structure in which an upper switching element and a lower switching element are serially connected and a reactor for temporarily storing energy based on a current from a power source is connected to a connection point of the both switching elements, into a desired voltage through switching of the switching elements, the voltage of the power source being input while utilizing the reactor, the method, comprising:

• detecting an electromotive voltage of the power source and a voltage on an output side of the voltage conversion device as a condition of the power source;
• setting a ratio range based on output characteristics of the power source corresponding to the detected condition of the power source, the ratio range being a range of ratios each between a period with the upper switching element remaining in an ON state and a period with the lower switching element remaining in an ON state;
• and
• controlling the ratio between the periods with the respective switching elements remaining in an ON state so-as to remain within the set ratio range,
• wherein
• the power source is chargeable and dischargeable, and,
• an output obtained through conversion into the desired voltage is supplied to a load.

A voltage conversion method for converting a voltage of a power source into a desired output voltage, comprising a reactor having one end connected to one end of the power source and a switching circuit having a first switching element positioned between other end of the reactor and an output terminal and a second switching element positioned between the other end of the reactor and other end of the power source,

• wherein
• a ratio between periods with the first and second switching elements remaining in an ON state is limited so as to remain in a predetermined range, based on permissible current capacities of the first and second switching elements by controlling such that a proportion of a period with either one of the first and second switching elements remaining in an ON state, relative to combined periods with the first and second switching elements relatively remaining in an ON state remains equal to or smaller than (Vbo−Rb×Ibmax)/Vc, Vbo representing an output voltage of the power source, Rb representing inner resistance of the power source, Ibmax representing a permissible current capacity of the switching element, and Vc representing the output voltage,
• the power source is chargeable and dischargeable, and,
• an output obtained through conversion into the desired voltage is supplied to a load.

A voltage conversion method for converting a voltage of a power source into a desired output voltage, comprising a reactor having one end connected to one end of the power source and a switching circuit having a first switching element positioned between other end of the reactor and an output terminal and a second switching element positioned between the other end of the reactor and other end of the power source,

• wherein
• a ratio between periods with the first and second switching elements remaining in an ON state is limited so as to remain in a predetermined range, based on a magnitude of a current flowing through the first or second switching element by controlling such that a proportion of a period with either one of the first and second switching element remaining in an ON state, relative to combined periods with the first and second switching element relatively remaining in an ON state remains equal to or smaller than (Vbo−Rb×Ibmax)/Vc, Vbo representing an output voltage of the power source, Rb representing inner resistance of the power source, Ibmax representing a maximum value of a current of the power source, and Vc representing the output voltage,
• the power source is chargeable and dischargeable, and,
• an output obtained through conversion into the desired voltage is supplied to a load.

A computer readable recording medium storing a control program for controlling a voltage conversion device having a reactor for temporarily storing energy based on a current from a power source which is chargeable and dischargeable, for converting a voltage of the power source, which is input while utilizing the reactor, into a desired voltage through switching of a switching element to output to a load, the program having a computer to execute:

• detecting an electromotive voltage and inner resistance of the power source as a condition of the power source;
• setting of a current range of the power source based on output characteristics of the power source corresponding to the detected condition of the power source;
• and
• switching control of the switching element such that the current of the power source remains within a current range set by a current range setting circuit.