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JP-7857198-B2 - Electronic circuits, power converters, and inverters

JP7857198B2JP 7857198 B2JP7857198 B2JP 7857198B2JP-7857198-B2

Inventors

  • 渡辺 宏樹
  • 上野 武司

Assignees

  • 株式会社東芝
  • 東芝デバイス＆ストレージ株式会社

Dates

Publication Date
20260512
Application Date
20220916

Claims (12)

  1. A current output circuit that outputs a drive current to a switching element, A first detection circuit for detecting the start timing of the voltage change between the output terminals of the switching element, A control circuit that causes the current output circuit to start outputting a first drive current in response to a command signal that instructs the switching operation of the switching element , A second detection circuit for detecting the completion timing of the voltage change between the output terminals of the switching element, A measurement circuit measures a third time from the time the first detection circuit detects the start timing of the voltage change between the output terminals until the second detection circuit detects the completion timing of the voltage change between the output terminals. Equipped with, The control circuit switches the drive current output from the current output circuit to a second drive current smaller than the first drive current, based on the start timing of the voltage change between the output terminals detected by the first detection circuit. When a first time has elapsed since the current output circuit started outputting the first drive current, the current output circuit switches the drive current output from the first drive current to the second drive current, and outputs the second drive current for a second period of time. Based on the third time measured by the measurement circuit, the value of the first time is corrected. electronic circuit.
  2. The electronic circuit according to claim 1, wherein when the first detection circuit detects the start timing of a voltage change between the output terminals, the control circuit switches the drive current output from the current output circuit to the second drive current.
  3. The electronic circuit according to claim 1, wherein the first detection circuit detects the start timing of the voltage change between the output terminals of the switching element by detecting the timing at which the voltage between the output terminals becomes equal to a predetermined first threshold voltage.
  4. The electronic circuit according to claim 3, wherein the first threshold voltage is set to a voltage within the range of 90% to 80% of the voltage between the output terminals when the switching element is non-conductive.
  5. The circuit further comprises a second detection circuit for detecting the completion timing of the voltage change between the output terminals of the switching element, The electronic circuit according to claim 2, wherein when the second detection circuit detects the completion timing of the voltage change between the output terminals, the control circuit switches the drive current output from the current output circuit to a third drive current that is larger than the second drive current.
  6. The electronic circuit according to claim 5, wherein the second detection circuit detects the completion timing of the voltage change between the output terminals by detecting the timing when the voltage between the output terminals of the switching element becomes equal to a predetermined second threshold voltage.
  7. The electronic circuit according to claim 6, wherein the second threshold voltage is set to a voltage within the range of 20% to 10% of the voltage between the output terminals when the switching element is non-conductive.
  8. The electronic circuit according to claim 1, wherein the control circuit increases the first time by a predetermined amount of time when the difference between the second time and the third time is greater than zero, and decreases the first time by the predetermined amount of time when the difference between the second time and the third time is zero or less.
  9. The electronic circuit according to claim 1 , wherein the control circuit modifies the value of the second drive current based on the third time.
  10. The electronic circuit according to claim 9, wherein the control circuit reduces the second drive current when the third time is shorter than a predetermined target time, and increases the second drive current when the third time is longer than the target time.
  11. Two switching elements constitute the arm pair, A power conversion device including two electronic circuits that supply drive current to each of the two switching elements, Each of the aforementioned electronic circuits is, A current output circuit that outputs a drive current to the switching element, A first detection circuit for detecting the start timing of the voltage change between the output terminals of the switching element, A control circuit that causes the current output circuit to start outputting a first drive current in response to a command signal that instructs the switching operation of the switching element , A second detection circuit for detecting the completion timing of the voltage change between the output terminals of the switching element, A measurement circuit measures a third time from the time the first detection circuit detects the start timing of the voltage change between the output terminals until the second detection circuit detects the completion timing of the voltage change between the output terminals. Equipped with, The control circuit switches the drive current output from the current output circuit to a second drive current smaller than the first drive current, based on the start timing of the voltage change between the output terminals detected by the first detection circuit. When a first time has elapsed since the current output circuit started outputting the first drive current, the current output circuit switches the drive current output from the first drive current to the second drive current, and outputs the second drive current for a second period of time. Based on the third time measured by the measurement circuit, the value of the first time is corrected. Power converter.
  12. A power conversion circuit having three sets of two switching elements that constitute an arm pair connected to a load, and two electronic circuits that supply drive current to each of the two switching elements. An inverter including , Each of the aforementioned electronic circuits is, A current output circuit that outputs a drive current to the switching element, A first detection circuit for detecting the start timing of the voltage change between the output terminals of the switching element, A control circuit that causes the current output circuit to start outputting a first drive current in response to a command signal that instructs the switching operation of the switching element , A second detection circuit for detecting the completion timing of the voltage change between the output terminals of the switching element, A measurement circuit measures a third time from the time the first detection circuit detects the start timing of the voltage change between the output terminals until the second detection circuit detects the completion timing of the voltage change between the output terminals. Equipped with, The control circuit switches the drive current output from the current output circuit to a second drive current smaller than the first drive current, based on the start timing of the voltage change between the output terminals detected by the first detection circuit. When a first time has elapsed since the current output circuit started outputting the first drive current, the current output circuit switches the drive current output from the first drive current to the second drive current, and outputs the second drive current for a second period of time. Based on the third time measured by the measurement circuit, the value of the first time is corrected. Inverter.

Description

This embodiment relates to an electronic circuit, a power conversion device, and an inverter. In the field of power electronics, semiconductor switching elements such as MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) and IGBTs (Insulated Gate Bipolar Transistors) are used. When a switching element is turned on, there is a delay (switching delay) between the start of the gate voltage increase and the start of drain current flow. To shorten this switching delay, the drive current supplied before the drain-source voltage begins to change is increased. However, if the drive current remains high even after the drain-source voltage begins to change, the rapid time change in the drain-source voltage can cause noise. “Rise and fall time regulation with current source MOSFET gate drivers”, Infineon Application Note Z8F69449874, June 19, 2020 A diagram showing the configuration of the motor control system according to Embodiment 1.A diagram showing the internal configuration of the electronic circuit in Embodiment 1.A timing chart illustrating the operation of the switching element driven by the drive current output from the current output circuit according to Embodiment 1.This diagram shows an example of current flowing in from the load side when both switching elements constituting an arm pair are in the OFF state.A diagram showing the internal configuration of the electronic circuit in Embodiment 2.A timing chart illustrating the operation of the switching element driven by the drive current output from the current output circuit according to Embodiment 2.A diagram showing the internal configuration of the electronic circuit in Embodiment 3. This embodiment will be described below with reference to the drawings. In the drawings, identical or corresponding elements are denoted by the same reference numerals, and detailed descriptions are omitted where appropriate. (Embodiment 1) Figure 1 shows the configuration of a motor control system 1 according to Embodiment 1. The motor control system 1 includes a three-phase AC motor 2 as a load, a DC power supply 3, switching elements 11a to 11f constituting a three-phase inverter circuit 10, and electronic circuits 100a to 100f that drive the switching elements 11a to 11f, respectively. The motor control system 1 also includes a detection circuit 4 that detects the operating state of the switching elements 11a to 11f, and a signal supply circuit 5 that supplies PWM signals to the electronic circuits 100a to 100f. In this embodiment, a motor is used as an example load, but any electronic or electrical device driven by an AC power supply may be used as the load. Switching elements 11a and 11b are N-channel MOSFETs. Switching elements 11a and 11b constitute the U-phase arm pair of the inverter circuit 10. Electronic circuit 100a controls the switching operation of switching element 11a, i.e., turn-on and turn-off, by controlling the drive current, i.e., gate current Ig, of switching element 11a. Electronic circuit 100b controls the switching operation of switching element 11b by controlling the drive current of switching element 11b. Similarly, switching elements 11c and 11d are N-channel MOSFETs. Switching elements 11c and 11d constitute the V-phase arm pair of the inverter circuit 10. Electronic circuit 100c controls the switching operation of switching element 11c by controlling its drive current. Electronic circuit 100d controls the switching operation of switching element 11d by controlling its drive current. Similarly, switching elements 11e and 11f are N-channel MOSFETs. Switching elements 11e and 11f constitute the W-phase arm pair of the inverter circuit 10. Electronic circuit 100e controls the switching operation of switching element 11e by controlling its drive current Ig. Electronic circuit 100f controls the switching operation of switching element 11f by controlling its drive current. The detection circuit 4 detects the operating state of the switching elements 11a to 11f based on the current values of the U, V, and W phases of the motor 2 and transmits this information to the signal supply circuit 5. Alternatively, the detection circuit 4 may detect the operating state of the switching elements 11a to 11f based on temperature information obtained by a temperature sensor (not shown) built into the motor 2. Or, the detection circuit 4 may detect the operating state of the switching elements 11a to 11f based on signals received from a control microcomputer (not shown). The signal supply circuit 5 supplies PWM signals to the electronic circuits 100a to 100f as command signals instructing the switching operation of the switching elements 11a to 11f, based on the operating status of the switching elements 11a to 11f received from the detection circuit 4. The signal supply circuit 5 and the electronic circuits 100a to 100f operate according to a system clock (not shown). Figure 2 shows the internal configuration of electronic circuits 100a to 100f. Since t