JP6152309B2 - Motor drive device - Google Patents

Description

  The present invention relates to a motor drive device, and more particularly to a motor drive device that drives a three-phase AC motor using a three-phase bridge drive circuit having switching elements connected in a three-phase bridge.

  In recent years, in vehicles such as automobiles, there is a so-called idling stop function in which an engine is automatically stopped when the vehicle is stopped by waiting for a signal or the like, and the engine is automatically restarted when the vehicle is started again. More and more are being adopted. By adopting such an idling stop function, exhaust gas and fuel consumption during idling can be suppressed, so that the burden on the environment can be reduced and energy can be saved.

  Under such circumstances, Patent Document 1 relates to an engine starting device, and when starting the engine, in order to reduce the influence of load torque at the time of starting, the starter motor is once rotated in the direction opposite to the normal engine rotating direction. Then, a configuration for rotating the starter motor in the normal engine rotation direction is disclosed.

  In addition, a motor drive device that drives and controls a starter motor as disclosed in Patent Document 1 using a three-phase bridge drive circuit has been proposed. When the starter motor is driven and controlled using a three-phase bridge drive circuit, the relative position between the coil and the magnet in the motor is detected by a phase sensor, and a three-phase switching element is connected to a predetermined energization pattern based on the detection result. Switching control is performed with. When driving such a starter motor, a desired torque can be obtained or the engine can be rotated by a desired angle by changing the amount of advance when the phase angle of the switching timing of the switching element is advanced. Can be made.

  Patent Document 2 relates to a charge control device that uses a three-phase AC motor as a three-phase AC generator, and relates to a drive control device that drives a three-phase AC generator using a three-phase bridge drive circuit. Monitor the change in the advance amount in order to cope with the possibility that the direction of the current flowing in the two-phase coil reverses and a sudden change in the current flow may occur when the advance amount of the current exceeds 60 degrees. When the advance angle is 60 degrees or more, all the switching elements are turned off to reset the current flow, so that the direction of the current flowing in the two-phase coil is reversed and the current flow is abrupt. The structure which prevents producing the change of is disclosed.

JP 2000-283010 A JP 2012-10456 A

However, according to the study of the present inventor, even if the configurations disclosed in Patent Document 1 and Patent Document 2 are combined, the phase angle is changed when the energization pattern of each switching element of the three-phase bridge drive circuit is changed. Even if the change in is within a predetermined angle, the direction of the current flowing in the two-phase coil may be reversed. For example, when the energization pattern is changed from the 180-degree energization mode to the 120-degree energization mode, even if the change in phase angle is within a predetermined angle, 2
It is conceivable that the direction of the current flowing in the phase coil is reversed, causing a sudden change in the current flow. In such a case, there is a tendency to lead to unstable or unnecessary operation of the three-phase AC motor. Conceivable.

  In other words, at present, a motor having a novel configuration that can suppress a sudden change in the direction of current flow even if an arbitrary energization pattern is changed in each switching element of the three-phase bridge drive circuit. There is a long-awaited realization of the drive device.

  The present invention has been made through the above-described studies, and suppresses a sudden change in the direction of current flow even if an arbitrary energization pattern is changed in each switching element of the three-phase bridge drive circuit. It is an object of the present invention to provide a motor drive device that can be used.

In order to achieve the above object, the present invention is a motor drive device for driving a three-phase AC motor, having a switching element connected to a three-phase bridge, and each of the switching elements performs a switching operation. A three-phase bridge drive circuit that converts the supplied direct current into alternating current and supplies the alternating current to the three-phase alternating current motor; and a control unit that switches the switching element in a predetermined energization pattern. In the motor drive device, when the control unit changes the energization pattern, the control unit compares the energization state of the switching element before the change with the energization state of the switching element after the change. In the AC motor, there is a phase in which the direction of current flow before the change and the direction of current flow after the change are opposite to each other. A determination unit that determines whether or not the phase is greater than or equal to a phase, and when the determination unit determines that the phase that is in the opposite direction is equal to or greater than two phases, all the switching elements are temporarily turned off. The three-phase bridge drive circuit includes a pair of the switching elements for each phase of the three-phase AC motor, and the determination unit determines the energization state of the pair of switching elements in the phase. For each phase, binarized every time, each binary value indicating the energized state of the pair of switching elements before the change, and each binary value indicating the energized state of the pair of switching elements after the change based on the correspondence relationship, the phase of the opposite direction that you determine the whether two or more phases to the first aspect.

  According to the first aspect of the present invention, when the controller that performs the switching operation of the switching element of the three-phase bridge drive circuit with the predetermined energization pattern changes the energization pattern, the energization state and change of the switching element before the change are changed. Whether or not there are two or more phases in which the direction in which the current before the change flows and the direction in which the current flows after the change are opposite in the three-phase AC motor by comparing the energization state of the subsequent switching element And a command unit that temporarily turns off all the switching elements when the determination unit determines that the number of phases in opposite directions is two or more. Even if an arbitrary energization pattern is changed in each switching element of the phase bridge drive circuit, a motor drive capable of suppressing a sudden change in the current flow direction. It is possible to realize a device.

According to the first aspect of the present invention, the three-phase bridge drive circuit has a pair of switching elements for each phase of the three-phase AC motor, and the determination unit determines the energization state of the pair of switching elements for each phase. Based on the corresponding relationship for each phase between each binary value indicating the energized state of the pair of switching elements before the change and each binary value indicating the energized state of the pair of switching elements after the change Whether or not the direction of the current flowing in the two-phase coil of the three-phase AC motor is reversed before and after the change of the energization pattern is determined by determining whether or not the opposite phase is two or more phases. This can be determined quickly and reliably by a simple method.

It is a schematic diagram which shows the structure of the motor drive device in embodiment of this invention. It is a figure which shows operation | movement of the motor drive device in this embodiment. Here, FIG. 2A is a diagram illustrating a timing chart of the motor driving device in the present embodiment, and FIG. 2B is a diagram illustrating an energization state before the change of the motor driving device in the present embodiment. Moreover, FIG.2 (c) is a figure which shows the electricity supply state after the change of the motor drive device in this embodiment. It is a figure which shows the correspondence of the energization state before the change of the motor drive device in this embodiment, and the energization state after a change, and Fig.3 (a) is the energization state before the change of the motor drive device in this embodiment. It is a figure which shows the 1st example of the correspondence with the energized state after a change, and FIG.3 (b) is the energized state before the change of the motor drive device in this embodiment, and the energized state after a change. It is a figure which shows the 2nd example of a correspondence. It is a figure which shows operation | movement of the motor drive device in the modification of embodiment of this invention. Here, FIG. 4A is a diagram illustrating a timing chart of the motor driving device in the present modification, and FIG. 4B is a diagram illustrating an energization state before the change of the motor driving device in the present modification. In addition, FIG. 4C is a diagram showing the energized state after the change of the motor drive device in the present modification.

  Hereinafter, a motor drive device according to an embodiment of the present invention will be described in detail with reference to the drawings as appropriate.

  FIG. 1 is a schematic diagram illustrating a configuration of a motor driving device according to the present embodiment.

  As shown in FIG. 1, the motor drive device 10 in the present embodiment includes a three-phase bridge drive circuit 20 and a control unit 30. In FIG. 1, in addition to the motor drive device 10, a three-phase AC motor 40, a phase sensor 50, and a power source 60 are also shown.

The three-phase bridge drive circuit 20 includes switching elements 21, 22, 23, 24, 25, and 26 that are connected in a three-phase bridge, and the switching elements 21, 22, 23, 24, 25 are controlled according to a control signal from the control unit 30. And 26 are turned on or off to convert the DC current supplied from the power supply 60 into a three-phase AC current each consisting of a rectangular wave, and supply the three-phase AC current to the three-phase AC motor 40. The switching elements 21, 22, 23, 24, 25, and 26 are typically transistors. In FIG. 1, for example, an N-type MOSFET (Metal-Oxide-Semiconductor Field-Effect) is used as an example.
(Transistor).

Specifically, the three-phase bridge drive circuit 20 corresponds to a pair of switching elements 21, 22, 23, 24, 25, and 26 for each of the three phases of U phase, V phase, and W phase. Have. That is, in the three-phase bridge drive circuit 20, a pair of U-phase switching elements 21 and switching elements 22 are electrically connected, and when the switching elements 21 are on and the switching elements 22 are off, U The phase driving voltage is set to the high level, and the U phase driving voltage is set to the low level when the switching element 21 is in the off state and the switching element 22 is in the on state. In the three-phase bridge drive circuit 20, the pair of switching elements 23 and the switching element 24 of the V phase are electrically connected, and when the switching element 23 is in the on state and the switching element 24 is in the off state, V When the phase driving voltage is set to the high level and the switching element 23 is in the off state and the switching element 24 is in the on state, the V phase driving voltage is set to the low level. Further, in the three-phase bridge drive circuit 20, a pair of W-phase switching elements 25 and a switching element 26 are electrically connected. When the switching element 25 is in an on state and the switching element 26 is in an off state, the W phase When the switching element 25 is in the off state and the switching element 26 is in the on state, the W-phase driving voltage is set to the low level.

  The switching element 21 includes a control terminal electrically connected to the command unit 32, one input terminal electrically connected to the high potential side of the power supply 60, and a connection terminal of the switching element 22 and the three-phase AC motor 40. And the other input terminal electrically connected to 44. The switching element 21 performs an on / off operation in accordance with a predetermined control signal applied to the control terminal from the command unit 32. When the switching element 21 is in an on state, a current flows from one input terminal to the other input terminal. Flows.

  The switching element 22 includes a control terminal electrically connected to the command unit 32, one input terminal electrically connected to the connection terminal 44 of the switching element 21 and the three-phase AC motor 40, and a low potential of the power supply 60. And the other input terminal electrically connected to the side. The switching element 22 is turned on / off according to a predetermined control signal applied from the command unit 32 to the control terminal. When the switching element 22 is in the on state, a current is passed from one input terminal to the other input terminal. Flowing.

  The switching element 23 includes a control terminal electrically connected to the command unit 32, one input terminal electrically connected to the high potential side of the power supply 60, and a connection terminal of the switching element 24 and the three-phase AC motor 40. 46, and the other input terminal electrically connected to 46. The switching element 23 is turned on / off in accordance with a predetermined control signal applied from the command unit 32 to the control terminal. When the switching element 23 is in the on state, a current flows from one input terminal to the other input terminal. Flowing.

  The switching element 24 includes a control terminal electrically connected to the command unit 32, one input terminal electrically connected to the connection terminal 46 of the switching element 23 and the three-phase AC motor 40, and a low potential of the power supply 60. And the other input terminal electrically connected to the side. The switching element 24 is turned on / off in accordance with a predetermined control signal applied from the command unit 32 to the control terminal. When the switching element 24 is in the on state, a current flows from one input terminal to the other input terminal. Flowing.

  The switching element 25 includes a control terminal electrically connected to the command unit 32, one input terminal electrically connected to the high potential side of the power supply 60, and a connection terminal of the switching element 26 and the three-phase AC motor 40. 45, and the other input terminal electrically connected to 45. The switching element 25 is turned on / off according to a predetermined control signal applied from the command unit 32 to the control terminal. When the switching element 25 is in the on state, a current is passed from one input terminal to the other input terminal. Flowing.

  The switching element 26 includes a control terminal electrically connected to the command unit 32, one input terminal electrically connected to the connection terminal 45 of the switching element 25 and the three-phase AC motor 40, and a low potential of the power supply 60. And the other input terminal electrically connected to the side. The switching element 26 is turned on / off in accordance with a predetermined control signal applied from the command unit 32 to the control terminal. When the switching element 26 is in the on state, a current flows from one input terminal to the other input terminal. Flowing.

The control unit 30 includes a determination unit 31 and a command unit 32 as functional blocks, and a U-phase coil 41, a V-phase coil 42, and a W-phase coil 43 in the three-phase AC motor 40 are not illustrated. Switching control for switching between the ON state and the OFF state of each of the switching elements 21, 22, 23, 24, 25, and 26 based on the detection signal of the phase sensor 50 that carries information on the rotation angle (rotation position) of the rotor. Do. A program that causes the determination unit 31 and the command unit 32 to function as functional blocks is stored in advance in a memory that is not illustrated.

  Based on the detection signal detected by the phase sensor 50, the determination unit 31 determines the phase angle of the rotor with respect to the stator provided with a magnet group (not shown) in each of the three-phase AC motors 40, that is, the phase angle of the three-phase AC motor 40. Based on these, the energization pattern of the switching elements 21, 22, 23, 24, 25 and 26 in the next phase angle range of the three-phase AC motor 40 is determined, and the determination result is sent to the command unit 32. Send the signal to carry.

  Specifically, the determination unit 31 determines the respective energization states in the energization patterns of the switching elements 21, 22, 23, 24, 25, and 26 in the 180-degree energization mode with the phase angle of the three-phase AC motor 40 being 60 degrees. In addition, each energization state in a new energization pattern for advancing those energization patterns by 90 degrees at the phase angle of the three-phase AC motor 40 is determined at a predetermined timing. Here, the 180-degree energization mode corresponds to the drive voltage applied to the U-phase coil 41, the V-phase coil 42, and the W-phase coil 43 being 180 degrees in terms of the phase angle of the three-phase AC motor 40, respectively. An energization mode that is continuously high.

  Further, the determination unit 31 has a new energization pattern for advancing the energization pattern of the switching elements 21, 22, 23, 24, 25, and 26 by 90 degrees with the phase angle of the three-phase AC motor 40 at a predetermined timing. When determining the current state of each of the current switching elements 21, 22, 23, 24, 25, and 26 before the change, and the switching elements 21, 22, 23, 24 in the new current pattern after the change, By comparing the respective energization states of 25 and 26, the energization pattern with respect to the direction of the drive current flowing through the coils 41, 42 and 43 of each phase of the three-phase AC motor 40 before the energization pattern is changed. Whether there are two or more phases in which the directions of the drive currents flowing in the coils 41, 42 and 43 of the respective phases of the three-phase AC motor 40 after the change of the phase are reversed When it is determined that there are two or more phases that are in opposite directions, it is determined that all the switching elements 21, 22, 23, 24, 25, and 26 are temporarily turned off, and the command A signal carrying the determination result is sent to the unit 32.

  The command unit 32 is electrically connected to the control terminals of the respective switching elements 21, 22, 23, 24, 25, and 26, and the switching elements 21, 22, 23, 24, 25, and By applying control signals having a high level and a low level to the 26 control terminals, they are turned on / off correspondingly.

  The three-phase AC motor 40 has a three-phase coil of a U-phase coil 41, a V-phase coil 42, and a W-phase coil 43 on the rotor side, and is arranged on the stator side around these. And is driven by receiving a three-phase alternating current from the three-phase bridge drive circuit 20.

  The U-phase coil 41 has a connection terminal 44 that is electrically connected to the other terminal of the U-phase switching element 21 and one terminal of the U-phase switching element 22. The V-phase coil 42 has a connection terminal 45 electrically connected to the other terminal of the V-phase switching element 23 and one terminal of the V-phase switching element 24. The W-phase coil 43 has a connection terminal 45 electrically connected to the other terminal of the W-phase switching element 25 and one terminal of the W-phase switching element 26.

The phase sensor 50 is typically a magnetic sensor using a Hall element or a magnetoresistive element, and changes the rotation angle (rotation position) of the rotor with respect to the stator provided with the magnet group of the three-phase AC motor 40 in time series. As a voltage signal to be detected, and the detection signal is determined by the determination unit 3
1 to send. Such a detection signal is a voltage signal in which high level and low level voltage levels appear alternately every 180 degrees, typically at the rotation angle of the rotor, and a U-phase coil 41 and a V-phase coil provided in the rotor. 42 and a three-phase voltage signal having different phases according to the rotational position of each of the W-phase coils 43.

  The power source 60 is a DC power source and supplies a DC current to the three-phase bridge drive circuit 20.

  Next, the operation of the motor drive device 10 according to the present embodiment having the above-described configuration will be described in detail with reference to FIGS. 2 and 3.

  FIG. 2 is a diagram illustrating the operation of the motor drive device according to the present embodiment. Here, FIG. 2A is a diagram illustrating a timing chart of the motor driving device in the present embodiment, and FIG. 2B is a diagram illustrating an energization state before the change of the motor driving device in the present embodiment. Moreover, FIG.2 (c) is a figure which shows the electricity supply state after the change of the motor drive device in this embodiment. FIG. 3 is a diagram showing a correspondence relationship between the energized state before the change of the motor drive device and the energized state after the change in the present embodiment, and FIG. 3A is a diagram before the change of the motor drive device in the present embodiment. FIG. 3B is a diagram illustrating a first example of the correspondence relationship between the energized state and the changed energized state, and FIG. 3B illustrates the energized state before and after the change of the motor drive device according to the present embodiment. It is a figure which shows the 2nd example of a corresponding relationship with an energized state. 2B and 2C, illustration of electrical connection wirings for the control terminals of the switching elements 21, 22, 23, 24, 25, and 26 is omitted.

  In FIG. 2A, (1) in the upper stage shows changes with time in detected voltage values of the U phase, V phase, and W phase detected by the phase sensor 50. The middle part (2) shows the energization pattern of the switching elements 21, 22, 23, 24, 25, and 26, and after the time t1, the switching elements 21, 22, 23, and 24 are advanced by 90 degrees. , 25 and 26 are shown. However, for convenience, (2) in the middle row turns off all the energization states of the switching elements 21, 22, 23, 24, 25, and 26 in the columns corresponding to the phase angle range of 60 degrees immediately after the time t1. The contents to be switched to are also shown. Further, (3) in the lower stage shows changes with time in drive voltage values applied to the U-phase coil 41, the V-phase coil 42, and the W-phase coil 43 of the three-phase AC motor 40, respectively. After t1, the time-dependent changes in the drive voltage values applied to the U-phase coil 41, V-phase coil 42, and W-phase coil 43 of the three-phase AC motor 40 when advanced by 90 degrees are shown. Yes.

  FIG. 3A shows a binarized state of “1” when one switching element is in an on state and “0” when one switching element is in an off state. The pattern of the energization state before the change in the pair of switching elements is shown in the leftmost column in a binary combination of “0”, “0”, “0”, “1”, and “1” “0”. The pattern of the energized state after the change in the pair of switching elements of each phase is a combination of binary numbers “0” “0”, “0” “1” and “1” “0”, and corresponds to the uppermost row. It is a truth table shown. Specifically, in the leftmost column and the uppermost row, “0” or “1” on the left corresponds to the energization state of the high-side switching elements 21, 23, and 25, and “ “0” or “1” corresponds to the energization state of the low-side switching elements 22, 24 and 26. It should be noted that here, when controlling the driving of the three-phase AC motor 40, it is impossible for both of the pair of switching elements of each phase to be on, so the combination of “1” and “1” is set as the energization state. Not done.

Here, in the region sandwiched between the leftmost column and the uppermost row in FIG. 3A, when switching the pair of switching elements of each phase from the current state before change to the current state after change. , Shows a change pattern of the direction of the drive current flowing in the corresponding coils 41, 42 and 43 of each phase, and the direction of the drive current flowing in the corresponding coils 41, 42 and 43 of each phase does not change. “0”, “0”, “0”, “1”, and “1” “0”, which are indicated by a combination of binary numbers, and the direction of the drive current flowing in the corresponding coils 41, 42, and 43 of each phase changes. It is indicated by a binary combination of “1” and “1”. That is, in this way, the logical operation for obtaining the combination of the binary numbers shown in the region sandwiched between the combination of the binary numbers shown in the leftmost column and the combination of the binary numbers shown in the uppermost row is exclusive. It is a logical OR operation.

  FIG. 3B is a table having the same information as that in FIG. 3A. However, the region between the leftmost column and the uppermost row in FIG. FIG. 3A shows a change pattern of the direction of the drive current flowing in the corresponding coils 41, 42 and 43 of each phase when the pair of switching elements are switched from the pre-change energization state to the post-change energization state. Are shown in a simplified manner, and the direction of the drive current flowing in the corresponding coils 41, 42, and 43 of each phase does not change is indicated by “OK”, and the corresponding coils 41, 42, and 43 of each phase. A change in the direction of the drive current flowing through the capacitor is indicated by “NG”. That is, FIG. 3B is table data created based on the truth table of FIG. 3A and is stored in advance in a memory not shown.

  Specifically, before time t1, the determination unit 31 of the control unit 30 rotates the rotation angles of the coils 41, 42, and 43 of each phase provided in the rotor shown in (1) in the upper part of FIG. Based on the detection signal of the phase sensor 50 according to (rotational position), the switching elements 21, 22, 23, 24 at 60 degrees in the range of the next phase angle shown in (2) in the middle of FIG. The energization patterns 25 and 26 are determined. The command unit 32 of the control unit 30 performs switching control to turn on or off each of the switching elements 21, 22, 23, 24, 25 and 26 according to the energization pattern determined by the determination unit 31. Thereby, in the coils 41, 42 and 43 of each phase, the drive voltage waveform shown in (3) in the lower part of FIG. At this time, the potential difference between the low level and the high level in each phase is denoted by V.

  That is, before the time t1, the determination unit 31 is based on the detection signal of the phase sensor 50 for every 60 degrees of the phase angle of the three-phase AC motor 40. One switching element is turned on and the other switching element is turned off, and one switching element of the pair of V-phase switching elements 23 and 24 is turned on and the other switching element is turned off. The switching elements 21, 22, 23, 24 are determined by turning on one of the pair of switching elements 25 and 26 in the W phase and turning off one of the other switching elements. , 25 and 26 are set.

  In the section R1 immediately before time t1, the energization states of the switching elements 21, 22, 23, 24, 25, and 26 are off, on, As shown in FIG. 2B, a drive current flows from the V phase and the W phase toward the U phase as shown in FIG. 2B. Specifically, the drive current supplied from the power supply 60 flows from the switching element 23 in the on state to the V-phase coil 42 of the three-phase AC motor 40 and from the switching element 25 in the on state to the three-phase AC motor. 40 flows through the W-phase coil 43, flows through the V-phase coil 42 and the W-phase coil 43 of the three-phase AC motor 40, flows into the U-phase coil 41, and is switched on via the U-phase coil 41. It flows through the element 22 and returns to the power source 60.

  Here, as shown in FIG. 2A, the control unit 30 advances the phase of the energization pattern by 90 degrees at time t1 when the three-phase AC motor 40 is driven in the 180-degree energization mode. Become.

  At this time, if the determination unit 31 performs advance of the energization pattern before actually performing advance of the energization pattern at time t1, the coils 41 and 42 of each phase of the three-phase AC motor 40 are assumed. And 43, the direction of the drive current flowing in the coils 41, 42 and 43 of each phase before the energization pattern advance angle, and the direction of the drive current flowing in the coils 41, 42 and 43 of each phase after the energization pattern advance angle, It is necessary to determine whether or not there are two or more phases in the opposite directions.

  Specifically, if advancement of the energization pattern is performed, as shown in (2) in the middle of FIG. 2A, in the section R1 immediately before time t1 and the section R2 immediately after time t1, In the U phase, the switching element 21 is switched from the off state to the on state, and the switching element 22 is switched from the on state to the off state. In the V phase, the switching element 23 is switched from the on state to the off state, and the switching element 24 is switched from the off state to the on state. Further, in the W phase, the switching element 25 is not switched in the on state and the switching element 26 is not switched in the off state.

  Thus, after the advancement of the energization pattern, as shown in FIG. 2C, the drive current flows from the U-phase coil 41 and the W-phase coil 43 toward the V-phase coil 42. Specifically, the current supplied from the power supply 60 flows from the switching element 21 in the on state to the U-phase coil 41 of the three-phase AC motor 40 and from the switching element 25 in the on state to the three-phase AC motor 40. To the W-phase coil 43, the U-phase coil 41 of the three-phase AC motor 40 and the W-phase coil 43 to the V-phase coil 42 of the three-phase AC motor 40. After that, it flows through the switching element 24 in the on state and returns to the power source 60.

  That is, in such a case, the direction of the drive current that flows through the coils 41, 42, and 43 of each phase shown in FIG. 2B and the drive that flows through the coils 41, 42, and 43 of each phase shown in FIG. Comparing the current direction, it can be seen that the directions of the drive currents flowing through the U-phase coil 41 and the V-phase coil 42 are reversed.

  In summary, the determination process of the determination unit 31 is performed based on the truth table of FIG.

  That is, in FIG. 3A, since the switching element 21 is in the OFF state and the switching element 22 is in the ON state in the U phase in the section R1 immediately before the time t1, the binary combination indicating the energization state is In the U phase in the section R2 immediately after the time t1, the switching element 21 is in the on state and the switching element 22 is in the off state. Therefore, the binary combination indicating the energized state is “1”. “0”. Accordingly, the determination unit 31 determines “0” and “1” indicating the energization state before and after the energization pattern advance angle of the switching element 21 and energization before and after the energization pattern advance angle of the switching element 22 from the truth table of FIG. From “1” and “0” indicating the state, a binary combination indicating the state of the U phase accompanying the advance angle of the energization pattern is obtained as “1” and “1”. That is, this is obtained by performing an exclusive OR operation on “0” and “1” indicating the energization state before and after the energization pattern advance angle of the switching element 21 to obtain “1”, and at the same time, the energization pattern advance angle of the switching element 22. By calculating the exclusive OR of “1” and “0” indicating the previous and subsequent energization states to obtain “1”, the binary combination indicating the U-phase state accompanying the advance angle of the energization pattern is “1”. "It is synonymous with" 1 ".

In FIG. 3A, in the V phase in the section R1 immediately before the time t1, the switching element 23 is in the on state and the switching element 24 is in the off state. 1 ”and“ 0 ”, and in the V phase in the section R2 immediately after the time t1, the switching element 21 is in the OFF state and the switching element 22 is in the ON state. Therefore, the binary combination indicating the energized state is“ 0 ”. It becomes “1”. Accordingly, the determination unit 31 determines from the truth table of FIG. 3A that “1” and “0” indicate the energization state before and after the energization pattern advance angle of the switching element 23 and energization before and after the energization pattern advance angle of the switching element 24. From “0” and “1” indicating the state, a binary combination indicating the state of the V phase accompanying the advance angle of the energization pattern is obtained as “1” and “1”. In other words, this obtains “1” by performing an exclusive OR operation on “1” and “0” indicating the energization state before and after the energization pattern advance angle of the switching element 23, and at the same time, the energization pattern advance angle of the switching element 24. “1” is obtained by performing an exclusive OR operation on “0” and “1” indicating the previous and subsequent energization states, thereby obtaining a combination of two values indicating the V-phase state accompanying the advance angle of the energization pattern “1”. "It is synonymous with" 1 ".

  Furthermore, in FIG. 3A, in the W phase in the section R1 immediately before time t1, the switching element 25 is in the on state and the switching element 26 is in the off state, so the binary combination indicating the energized state is “ 1 ”and“ 0 ”, and in the W phase in the section R2 immediately after the time t1, the switching element 25 is in the on state and the switching element 26 is in the off state. Therefore, the binary combination indicating the energized state is“ 1 ”. It becomes “0”. Therefore, from the truth table in FIG. 3A, the determination unit 31 indicates “1” “1” indicating the energization state before and after the energization pattern advance angle of the switching element 25 and energization before and after the energization pattern advance angle of the switching element 26. From “0” and “0” indicating the state, two values indicating the state of the W phase accompanying the advance angle of the energization pattern are obtained as “0” and “0”. In other words, this obtains “0” by performing an exclusive OR operation on “1” and “1” indicating energization states before and after the energization pattern advance angle of the switching element 25, and at the same time, obtains “0” as the energization pattern advance angle of the switching element 26. By calculating the exclusive OR of “0” and “0” indicating the previous and subsequent energization states to obtain “0”, a binary combination indicating the state of the W phase accompanying the advance angle of the energization pattern is set to “0”. "It is synonymous with" 0 ".

  As a result, the determination unit 31 has two phases of “1” and “1” at the time t1 when the energization pattern is advanced. In the coils 41, 42 and 43, the direction of the drive current flowing through the coils 41, 42 and 43 of each phase before the energization pattern advance and the drive flowing through the coils 41, 42 and 43 of each phase after the advance of the energization pattern It is determined that there are two or more phases opposite to the direction of the current, and it is determined that all the switching elements 21, 22, 23, 24, 25, and 26 are temporarily turned off, and the command A signal carrying the determination result is sent to the unit 32.

  Here, it is more preferable in terms of efficiency that the determination process of the determination unit 31 is to retrieve a logical operation result with reference to the table data of FIG. When the determination unit 31 determines with reference to the table of FIG. 3B, there are two phases of “NG” at the time t1 when the energization pattern is advanced, that is, U phase and V phase. Therefore, in the coils 41, 42, and 43 of each phase of the three-phase AC motor 40, the determination unit 31 determines the direction of the drive current that flows in the coils 41, 42, and 43 of each phase before the energization pattern advance, It is determined that there are two or more phases in which the direction of the drive current flowing in the coils 41, 42 and 43 of each phase after the corner is opposite, and all the switching elements 21, 22, 23, 24, 25 and 26 is temporarily turned off, and a signal carrying the determination result is sent to the command unit 32.

  Then, the command unit 32 maintains the switching elements 21, 24, and 26 in the OFF state in the section R2 according to the transmission signal from the determination unit 31, and switches the switching elements 22, 23, and 25 from the ON state to the OFF state. By switching to, all the switching elements 21, 22, 23, 24, 25, and 26 are controlled to be temporarily turned off.

After that, the determination unit 31 repeats the same processing, and in each of the coils 41, 42, and 43 of each phase of the three-phase AC motor 40, the drive current flowing through the coils 41, 42, and 43 of each phase before the energization pattern advance angle is determined. It is confirmed that there are no two or more phases in which the direction and the direction of the drive current flowing through the coils 41, 42 and 43 of each phase after the energization pattern advance angle are opposite to each other. The phase of the energization pattern is advanced by 90 degrees. In addition, after switching off all the switching elements 21, 22, 23, 24, 25, and 26 temporarily without repeating this process as needed, the phase of the energization pattern of the three-phase AC motor 40 is changed. The advance of 90 degrees may be selected, or the 180-degree conduction pattern of the conventional three-phase AC motor 40 may be continuously executed.

  Next, the operation of the motor drive device 10 according to the modification of the present embodiment will be described in detail with reference to FIG. The configuration of the motor drive device 10 in this modification is the same as that in the above-described embodiment, and only the operation is different.

  FIG. 4 is a diagram showing the operation of the motor drive device according to a modification of the embodiment of the present invention, and the mode is the same as that of FIG. Here, FIG. 4A is a diagram illustrating a timing chart of the motor driving device in the present modification, and FIG. 4B is a diagram illustrating an energization state before the change of the motor driving device in the present modification. In addition, FIG. 4C is a diagram showing the energized state after the change of the motor drive device in the present modification.

  Specifically, the determination unit 31 determines the respective energization states in the energization patterns of the switching elements 21, 22, 23, 24, 25, and 26 in the 180-degree energization mode with the phase angle of the three-phase AC motor 40 being 60 degrees. In addition, each energization state for changing the energization pattern to a 120-degree energization pattern is determined at a predetermined timing. Here, the 120-degree energization mode corresponds to the drive voltages applied to the U-phase coil 41, the V-phase coil 42, and the W-phase coil 43, respectively, 120 degrees at the phase angle of the three-phase AC motor 40. This is an energization mode in which the level is continuously high, and an intermediate level drive voltage between the high level and the low level is set around the 120 degree interval.

  Furthermore, when the determination unit 31 determines a new energization pattern for changing the energization pattern of the switching elements 21, 22, 23, 24, 25, and 26 at a predetermined timing, the current switching before the change is determined. Compare the energization state of each of the elements 21, 22, 23, 24, 25, and 26 with the energization state of each of the switching elements 21, 22, 23, 24, 25, and 26 in the new energization pattern after the change. Thus, each phase of the three-phase AC motor 40 after the change of the energization pattern is compared with the direction of the drive current flowing through the coils 41, 42 and 43 of each phase of the three-phase AC motor 40 before the change of the energization pattern. It is determined whether there are two or more phases in which the directions of the drive currents flowing in the coils 41, 42 and 43 are reversed, and there are two or more phases in the opposite direction. And if it is determined, it decided to temporarily turned off all the switching elements 21, 22 and 26, and sends a signal carrying the result of the determination to the command unit 32.

  Specifically, before time t1, the determination unit 31 of the control unit 30 rotates the rotation angles of the coils 41, 42, and 43 of each phase provided in the rotor shown in (1) in the upper part of FIG. Based on the detection signal of the phase sensor 50 according to (rotational position), the switching elements 21, 22, 23, 24 at 60 degrees in the range of the next phase angle shown in (2) of the middle stage of FIG. The energization patterns 25 and 26 are determined. The command unit 32 of the control unit 30 performs switching control to turn on or off each of the switching elements 21, 22, 23, 24, 25 and 26 according to the energization pattern determined by the determination unit 31. Thereby, in the coils 41, 42 and 43 of each phase, the drive voltage waveform shown in (3) in the lower stage of FIG.

In the section R1 immediately before the time t1, the energization states of the switching elements 21, 22, 23, 24, 25, and 26 are off, off, As shown in FIG. 4B, a drive current flows from the W phase to the V phase and the U phase as shown in FIG. 4B. Specifically, the current supplied from the power supply 60 flows from the switching element 25 in the on state to the W-phase coil 43 of the three-phase AC motor 40, and then passes through the W-phase coil 43 of the three-phase AC motor 40. It flows through the phase coil 41 and the V-phase coil 42, returns to the power source 60 through the U-phase coil 41 and the switching element 22 in the on state, and passes through the V-phase coil 42 and the switching element 24 in the on state. Return to power supply 60.

  Here, as shown in FIG. 4A, the control unit 30 changes the energization pattern to the 120-degree energization mode at time t1 when the three-phase AC motor 40 is driven in the 180-degree energization mode. Become.

  At this time, if the determination unit 31 changes the energization pattern before actually changing the energization pattern at time t1, the coils 41, 42, and 43 of each phase of the three-phase AC motor 40 are temporarily changed. , The direction of the drive current flowing through the coils 41, 42 and 43 of each phase before the energization pattern change and the direction of the drive current flowing through the coils 41, 42 and 43 of each phase after the energization pattern change are opposite to each other It is necessary to determine whether there are two or more phases.

  Specifically, if the energization pattern is changed, as shown in (2) in the middle of FIG. 4A, in the section R1 immediately before time t1 and the section R2 immediately after time t1, U In the phase, switching element 21 is switched from the OFF state to the ON state, and switching element 22 is switched from the ON state to the OFF state. Further, in the V phase, the switching element 23 is not switched in the off state, and the switching element 24 is switched from the on state to the off state. In the W phase, the switching element 25 is switched from the on state to the off state, and the switching element 26 is switched from the off state to the on state.

  As a result, after the energization pattern is changed, a drive current flows from the U-phase coil 41 toward the W-phase coil 43 as shown in FIG. Specifically, the current supplied from the power source 60 flows from the switching element 21 that is turned on to the U-phase coil 41 of the three-phase AC motor 40 and passes through the U-phase coil 41 of the three-phase AC motor 40. The electric current flows through the W-phase coil 43 of the phase AC motor 40, and further flows through the switching element 26 in the ON state via the W-phase coil 43 to return to the power supply 60.

  That is, in such a case, the direction of the drive current that flows through the coils 41, 42, and 43 of each phase shown in FIG. 4B and the drive that flows through the coils 41, 42, and 43 of each phase shown in FIG. Comparing the current directions, it can be seen that the directions of the drive currents flowing through the U-phase coil 41 and the W-phase coil 43 are reversed.

  In summary, the determination process of the determination unit 31 is performed based on the truth table of FIG.

That is, in FIG. 3A, since the switching element 21 is in the OFF state and the switching element 22 is in the ON state in the U phase in the section R1 immediately before the time t1, the binary combination indicating the energization state is In the U phase in the section R2 immediately after the time t1, the switching element 21 is in the on state and the switching element 22 is in the off state. Therefore, the binary combination indicating the energized state is “1”. “0”. Therefore, from the truth table of FIG. 3A, the determination unit 31 indicates “0” “1” indicating the energization state before and after the change of the energization pattern of the switching element 21 and the energization state before and after the change of the energization pattern of the switching element 22. From the “1” and “0” shown, a binary combination indicating the state of the U phase accompanying the change of the energization pattern is obtained as “1” and “1”. That is, this is obtained by performing an exclusive OR operation on “0” and “1” indicating the energization state before and after the change of the energization pattern of the switching element 21 to obtain “1”, and before and after the energization pattern of the switching element 22 is changed. By calculating the exclusive OR of “1” and “0” indicating the energization state to obtain “1”, the combination of the binary values indicating the state of the U phase accompanying the change of the energization pattern is “1” and “1”. It is synonymous with "

  In FIG. 3A, in the V phase in the section R1 immediately before time t1, the switching element 23 is in the off state and the switching element 24 is in the on state. In the V phase in the section R2 immediately after the time t1, the switching element 21 is in the off state and the switching element 22 is in the off state. Therefore, the binary combination indicating the energized state is “0”. It becomes “0”. Therefore, from the truth table in FIG. 3A, the determination unit 31 indicates “0” and “1” indicating the energization state before and after the change of the energization pattern of the switching element 23 and the energization state before and after the change of the energization pattern of the switching element 24. From the “0” and “0” shown, a binary combination indicating the state of the V phase accompanying the change of the energization pattern is obtained as “0” and “1”. That is, this is obtained by performing an exclusive OR operation on “0” and “0” indicating the energization state before and after the energization pattern change of the switching element 23 to obtain “0” and before and after the energization pattern change of the switching element 24. By calculating the exclusive OR of “1” and “0” indicating the energization state to obtain “1”, the binary combination indicating the state of the V phase accompanying the change of the energization pattern is “0” and “1”. It is synonymous with "

  Furthermore, in FIG. 3A, in the W phase in the section R1 immediately before time t1, the switching element 25 is in the on state and the switching element 26 is in the off state, so the binary combination indicating the energized state is “ 1 ”and“ 0 ”, and in the W phase in the section R2 immediately after the time t1, the switching element 25 is in the OFF state and the switching element 26 is in the ON state, so the binary combination indicating the energized state is“ 0 ”. It becomes “1”. Therefore, from the truth table of FIG. 3A, the determination unit 31 indicates “1” “0” indicating the energization state before and after the change of the energization pattern of the switching element 25 and the energization state before and after the change of the energization pattern of the switching element 26. From the “0” and “1” shown, the binary value indicating the state of the W phase accompanying the change of the energization pattern is obtained as “1” and “1”. This is an exclusive OR operation of “1” and “0” indicating the energization state before and after the energization pattern change of the switching element 25 to obtain “1” and the energization state before and after the energization pattern change of the switching element 26. By calculating the exclusive OR of “0” and “1” indicating “1” to obtain “1”, the binary combination indicating the state of the W phase accompanying the change of the energization pattern is set to “1” and “1” It is synonymous with what I asked for.

  As a result, at the time t1 when the energization pattern is changed, the determination unit 31 has two phases of “1” and “1”, the U phase and the W phase. In the coils 41, 42 and 43, the direction of the drive current flowing in the coils 41, 42 and 43 of each phase before the energization pattern change, and the direction of the drive current flowing in the coils 41, 42 and 43 of each phase after the energization pattern change It is determined that there are two or more phases in opposite directions, and it is determined that all the switching elements 21, 22, 23, 24, 25 and 26 are temporarily turned off, and the command unit 32 is A signal carrying the determination result is transmitted.

  Here, it is more preferable in terms of efficiency that the determination process of the determination unit 31 is to retrieve a logical operation result with reference to the table data of FIG. When the determination unit 31 determines with reference to the table of FIG. 3B, there are two phases of “NG” at time t1 when the energization pattern is changed, that is, U phase and W phase. In the coils 41, 42, and 43 of each phase of the three-phase AC motor 40, the determination unit 31 determines the direction of the drive current that flows through the coils 41, 42, and 43 of each phase before the energization pattern change, and after the change of the energization pattern It is determined that there are two or more phases in which the directions of the drive currents flowing in the coils 41, 42, and 43 of each phase are opposite to each other, and all the switching elements 21, 22, 23, 24, 25, and 26 are temporarily To turn it off, and sends a signal carrying the determination result to the command unit 32.

  The command unit 32 maintains the switching elements 21, 22, 23, and 26 in the OFF state in the section R2 according to the transmission signal from the determination unit 31, and switches the switching elements 24 and 25 from the ON state to the OFF state. By switching to, all the switching elements 21, 22, 23, 24, 25, and 26 are controlled to be temporarily turned off.

  Thereafter, the determination unit 31 repeats the same processing, and in the coils 41, 42, and 43 of each phase of the three-phase AC motor 40, the direction of the drive current that flows in the coils 41, 42, and 43 of each phase before the energization pattern is changed. And the energization pattern of the three-phase AC motor 40 by confirming that there are no two or more phases in which the directions of the drive currents flowing through the coils 41, 42 and 43 of the respective phases after the energization pattern change are opposite. Is changed to the 120-degree energization mode. If necessary, it may be selected to change the energization pattern of the three-phase AC motor 40 to the 120-degree energization mode without repeating such processing, or the 180-degree energization of the previous three-phase AC motor 40 may be selected. You can continue to run the pattern.

  In the present embodiment including the above-described modifications, the motor driving device 10 may advance or retard the phase of the energization mode by a desired angle other than 90 degrees, and advance or retard as such. The energization mode for retarding may be other than the 180-degree energization mode. Further, the motor drive device 10 may change the energization mode to an energization mode for energizing in a desired phase angle range other than the 120-degree energization mode, and the energization mode before the change is other than the 180-degree energization mode. There may be.

  Further, when creating the truth table shown in FIG. 3A, the direction of the drive current flowing through the coil of each phase before the energization pattern change and the drive current flowing through the coil of each phase after the energization pattern change are made. As long as the phase in which the direction is opposite can be clearly defined, other arithmetic rules such as logical sum operation and arithmetic addition may be used in addition to the exclusive OR operation.

  According to the configuration of the present embodiment described above, the control unit 30 that switches the switching elements 21, 22, 23, 24, 25, and 26 of the three-phase bridge drive circuit 20 with a predetermined energization pattern changes the energization pattern. At this time, by comparing the energized state of the switching elements 21, 22, 23, 24, 25, and 26 before the change with the energized state of the switching elements 21, 22, 23, 24, 25, and 26 after the change, 3 In the phase AC motor 40, a determination unit 31 that determines whether or not the phase in which the current flow direction before the change and the current flow direction after the change are in opposite directions is two or more, and the determination unit 31 reverses the reverse direction. And a command unit 32 that temporarily turns off all the switching elements 21, 22, 23, 24, 25, and 26 when it is determined that the number of phases becomes two or more. As a result, even if an arbitrary energization pattern is changed in each of the switching elements 21, 22, 23, 24, 25, and 26 of the three-phase bridge drive circuit 20, a sudden change occurs in the direction of current flow. It is possible to realize the motor drive device 10 that can suppress the above.

  Further, according to the configuration of the present embodiment, the three-phase bridge drive circuit 20 includes a pair of switching elements 21, 22, 23, 24, 25, and 26 for each phase of the three-phase AC motor 40, and the determination unit 31. The binarization of the energization state of the pair of switching elements 21, 22, 23, 24, 25 and 26 for each phase, and the energization state of the pair of switching elements 21, 22, 23, 24, 25 and 26 before change In the opposite direction based on the corresponding relationship for each phase between each of the binary values indicating the energized state of the pair of switching elements 21, 22, 23, 24, 25 and 26 after the change. By determining whether or not there are two or more phases, the direction of the current flowing in the two-phase coils 41, 41 and 43 of the three-phase AC motor 40 is reversed before and after the energization pattern is changed. Whether or not And it can be reliably determined.

  In the present invention, the type, arrangement, number, and the like of the members are not limited to the above-described embodiments, and the constituent elements thereof are appropriately replaced with those having the same operational effects, and the gist of the invention is not deviated. Of course, it can be appropriately changed within the range.

  As described above, according to the present invention, even if an arbitrary energization pattern is changed in each switching element of the three-phase bridge drive circuit, it is possible to suppress a sudden change in the current flowing direction. A motor drive device can be provided, and is expected to be widely applicable to motor drive devices such as vehicles because of its general-purpose universal character.

DESCRIPTION OF SYMBOLS 10 ... Motor drive device 20 ... Three-phase bridge drive circuit 21 ... Switching element 22 ... Switching element 23 ... Switching element 24 ... Switching element 25 ... Switching element 26 ... Switching element 30 ... Control part 31 ... Determination part 32 ... Command part 40 ... Three-phase drive motor 41 ... U-phase coil 42 ... V-phase coil 43 ... W-phase coil 50 ... Phase sensor 60 ... Power supply R1, R11 ... Section immediately before mode change R2, R12 ... Section immediately after mode change

Claims (1)

A motor driving device for driving a three-phase AC motor,
A three-phase bridge drive having a switching element connected to a three-phase bridge, wherein the switching element performs a switching operation to convert the supplied direct current into an alternating current and supply the alternating current to the three-phase alternating current motor. Circuit,
A control unit for switching the switching element in a predetermined energization pattern;
In a motor drive device comprising:
The controller is
When changing the energization pattern, by comparing the energization state of the switching element before the change and the energization state of the switching element after the change, the current before the change flows in the three-phase AC motor A determination unit that determines whether or not the phase in which the direction and the direction in which the current flows after the change is opposite is two or more;
A command unit that temporarily turns off all the switching elements when the determination unit determines that the phase in the opposite direction is two or more phases; and
Equipped with a,
The three-phase bridge drive circuit has a pair of switching elements for each phase of the three-phase AC motor, and the determination unit binarizes the energization state of the pair of switching elements for each phase, and Based on the corresponding relationship for each phase of each binary value indicating the energized state of the pair of switching elements before and each binary value indicating the energized state of the pair of switching elements after the change, It is determined whether the said phase which becomes a reverse direction is two or more phases, The motor drive device characterized by the above-mentioned .

Images