Driving device

Abstract

To suppress occurrence of a torque step difference of a motor in switching between one-side driving mode and both-side driving mode.SOLUTION: A driving device controls first and second inverters based on d-axis and q-axis current commands based on a torque command of a motor in one-side driving mode in which only one of the first and second inverters is driven or in both-side driving mode in which both the first and second inverters are driven. In this case, in one-side driving mode, the d-axis and q-axis current commands are set using the torque command and a first current command map, and in both-side driving mode, the d-axis and q-axis current commands are set using the torque command and a second current command map, where the first and second current command maps are determined such that the same torque is output for the same torque command.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a drive device. [Background technology]

[0002] A conventional drive device has been proposed, which includes a power storage device, a motor having a three-phase open winding, a first inverter connected to a power line to which the power storage device is connected and connected to one end of the three-phase open winding and having a plurality of first switching elements, a second inverter connected to the power line and connected to the other end of the three-phase open winding and having a plurality of second switching elements, and a switch attached to the power line between the first and second inverters (see, for example, Patent Document 1). This drive device can operate in a single-sided drive mode in which the switch is turned off, the second inverter is neutral-connected, and the first inverter is switch-driven. It can also operate in a double-sided drive mode in which the switch is turned on and the first and second inverters are switch-driven. When switching from the single-sided drive mode to the double-sided drive mode, the amount of power of the second inverter is gradually increased from zero, and when switching from the double-sided drive mode to the single-sided drive mode, the amount of power of the second inverter is gradually decreased to zero. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-137408 Summary of the Invention [Problem to be solved by the invention]

[0004] In such a drive unit, the motor is driven with a Y connection in single-side drive mode and a Delta connection in double-side drive mode, resulting in different motor characteristics. Therefore, if the inverter is controlled using the same d-axis and q-current commands for the motor torque command in both single-side drive mode and double-side drive mode, the motor torque may differ. Therefore, a torque step in the motor may occur when switching between single-side drive mode and double-side drive mode.

[0005] The main object of the drive device of the present disclosure is to suppress the occurrence of a torque step in the motor when switching between the single-side drive mode and the double-side drive mode. [Means for solving the problem]

[0006] The driving device of the present disclosure employs the following means to achieve the above-mentioned main object.

[0007] The drive device of the present disclosure includes a power storage device, a motor having a three-phase open winding, a first inverter connected to a power line to which the power storage device is connected and connected to one end of the three-phase open winding and having a plurality of first switching elements, a second inverter connected to the power line and connected to the other end of the three-phase open winding and having a plurality of second switching elements, a switch attached to the power line between the first inverter and the second inverter, and a one-sided drive mode in which only one of the first and second inverters is switched and driven, or a one-sided drive mode in which only one of the first and second inverters is switched and driven, and a control device that controls the first and second inverters based on d-axis and q-axis current commands based on a torque command of the motor in a double-sided drive mode in which both inverters are switched-drived, wherein the control device sets the d-axis and q-axis current commands using the torque command and a first current command map in the single-sided drive mode, and sets the d-axis and q-axis current commands using the torque command and a second current command map in the double-sided drive mode, and the first and second current command maps are defined so that the same torque is output for the same torque command.

[0008] In the drive device of the present disclosure, in single-sided drive mode, the d-axis and q-axis current commands are set using a torque command and a first current command map, and in double-sided drive mode, the d-axis and q-axis current commands are set using a torque command and a second current command map. In this case, the first and second current command maps are defined so that the same torque is output for the same torque command. This makes it possible to prevent a torque step from occurring in the motor when switching between single-sided drive mode and double-sided drive mode. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic configuration diagram of a drive device according to an embodiment of the present disclosure. [Figure 2] FIG. 3 is a functional block diagram showing an example of a functional block in controlling a first inverter and a second inverter. [Figure 3] 10 is a flowchart illustrating an example of a current command setting process. DETAILED DESCRIPTION OF THE INVENTION

[0010] A mode (embodiment) for carrying out the present disclosure will be described with reference to the drawings. Fig. 1 is a schematic configuration diagram of a drive device 20 according to an embodiment of the present disclosure. As shown in the figure, the drive device 20 according to the embodiment includes a battery 22 as an electricity storage device, a motor 24, a first inverter 30, a second inverter 32, a switch 34, and an electronic control unit 50 as a control device. The drive device 20 is mounted, for example, on an electric vehicle that runs using power from the motor 24, or a hybrid vehicle that has an engine in addition to the motor 24.

[0011] The battery 22 is configured as, for example, a lithium ion secondary battery or a nickel-metal hydride secondary battery, and has a positive terminal connected to a positive power line 24p and a negative power line 24n, respectively. Smoothing capacitors 26 are attached to the positive power line 24p and the negative power line 24n.

[0012] The motor 24 is configured as a synchronous generator motor having a rotor with a permanent magnet embedded in the rotor core, and a stator with three-phase (U-phase, V-phase, W-phase) windings wound around the stator core. The U-phase, V-phase, and W-phase windings are open windings, with a first inverter 30 connected to one end of each winding and a second inverter 32 connected to the other end of each winding.

[0013] The first inverter 30 is connected to the positive power line 24p and the negative power line 24n to which the battery 22 is connected, and includes six transistors T11-T16 as first switching elements and six diodes D11-D16 connected in parallel to each of the six transistors T11-T16. Among the transistors T11-T16, pairs of two transistors (transistor T11 and transistor T14, transistor T12 and transistor T15, and transistor T13 and transistor T16) are arranged so as to form a source side and a sink side with respect to the positive power line 24p and the negative power line 24n. Furthermore, each of the connection points of the paired transistors T11-T16 is connected to one end of the U-phase, V-phase, and W-phase windings of the motor 24. Hereinafter, of the transistors T11-T16 of the first inverter 30, the transistors T11-T13 may be referred to as the upper arm, and the transistors T14-T16 may be referred to as the lower arm.

[0014] The second inverter 32 is connected to the positive power line 24p and negative power line 24n, which are connected to the battery 22, with the first inverter 30 sandwiched between them. The second inverter 32 includes six transistors T21-T26 as second switching elements and six diodes D21-D26 connected in parallel to each of the six transistors T21-T26. Of the transistors T21-T26, pairs of two transistors (transistor T21 and transistor T24, transistor T22 and transistor T25, and transistor T23 and transistor T26) are arranged on the source and sink sides of the positive power line 24p and negative power line 24n. The connection points of the paired transistors T21-T26 are connected to the other ends of the U-phase, V-phase, and W-phase windings of the motor 24, respectively. Hereinafter, among the transistors T21 to T26 of the second inverter 32, the transistors T21 to T23 may be referred to as an upper arm, and the transistors T24 to T26 may be referred to as a lower arm.

[0015] The switch 34 is attached between the first inverter 30 and the second inverter 32 on the positive power line 24p.

[0016] The electronic control unit 50 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports, as well as various drive circuits and logic ICs. The electronic control unit 50 receives signals from various sensors via its input ports. For example, the electronic control unit 50 receives a voltage Vb from a voltage sensor 22v that detects the voltage of the battery 22, a current Ib from a current sensor 22i that detects the current of the battery 22, and a voltage Vc from a voltage sensor 26v that detects the voltage of the capacitor 26. The electronic control unit 50 also receives a rotational position θm from a rotational position sensor 24a that detects the rotational position of the rotor of the motor 24, and phase currents Iu, Iv, and Iw from current sensors 24u, 24v, and 24w that detect the phase currents of each phase of the motor 24. The electronic control unit 50 outputs various control signals via its output ports. For example, the electronic control unit 50 outputs a control signal to the transistors T11 to T16 of the first inverter 30, a control signal to the transistors T21 to T26 of the second inverter 32, and a control signal to the switch 34. The electronic control unit 50 calculates the charge storage rate SOC of the battery 22 based on the integrated value of the current Ib of the battery 22, and calculates the electrical angle θe and the rotation speed Nm of the motor 24 based on the rotation position θm of the rotor of the motor 24.

[0017] The driving device 20 of this embodiment switches between a single-side driving mode in which only one of the first inverter 30 and the second inverter 32 is switched and driven, and a double-side driving mode in which both the first inverter 30 and the second inverter 32 are switched and driven, based on the states of the motor 24, the first inverter 30, and the second inverter 32. In the single-side driving mode, the switch 34 is turned off, the transistors T21 to T23 of the upper arm of the second inverter 32 are turned on, and the transistors T24 to T26 of the lower arm are turned off, and the transistors T11 to T16 of the first inverter 30 are switched and driven, thereby driving the motor 24 in a Y-connection. That is, the U-phase, V-phase, and W-phase of the motor 24 are neutral-connected by the transistors T21 to T23 that are turned on, and the motor 24 is driven by the first inverter 30 as a Y-connection motor. In the double-sided drive mode, the switch 34 is turned on, and the transistors T11 to T16 of the first inverter 30 are switched and driven, and the transistors T21 to T26 of the second inverter 32 are switched and driven, thereby driving the motor 24 in a delta connection.

[0018] 2 is a functional block diagram showing an example of functional blocks in the control of the first inverter 30 and the second inverter 32 by the electronic control unit 50. The electronic control unit 50 includes, as functional blocks, a current command generation unit 61, a coordinate conversion unit 62, a current control unit 63, a coordinate conversion unit 64, and drive signal generation units 65 and 66.

[0019] A current command generation unit 61 sets d-axis and q-axis current commands Id*, Iq* based on a torque command Tm* of the motor 24 through a current command setting process described below. A coordinate conversion unit 62 performs coordinate conversion (three-phase to two-phase conversion) of U-, V-, and W-phase phase currents Iu, Iv, and Iw into d-axis and q-axis currents Id and Iq using the electrical angle θe of the motor 24. A current control unit 63 calculates d-axis and q-axis voltage commands Vd*, Vq* through current feedback control so that differences between the d-axis and q-axis currents Id, Iq and the current commands Id*, Iq* are canceled out. A coordinate conversion unit 64 performs coordinate conversion (two-phase to three-phase conversion) of the d-axis and q-axis voltage commands Vd*, Vq* into U-phase, Vv*, and W-phase voltage commands Vw using the electrical angle θe of the motor 24. A drive signal generator 65 generates drive signals for the transistors T11 to T16 of the first inverter 30 based on the U-, V-, and W-phase voltage commands Vu*, Vv*, and Vw and the drive mode (single-sided drive mode or double-sided drive mode), and drives and controls the transistors T11 to T16 based on these signals. A drive signal generator 66 generates drive signals for the transistors T21 to T26 of the second inverter 32 based on the U-, V-, and W-phase voltage commands Vu*, Vv*, and Vw and the drive mode (single-sided drive mode or double-sided drive mode), and drives and controls the transistors T21 to T26 based on these signals. Note that in single-sided drive mode, as described above, the upper-arm transistors T21 to T23 are turned on and the lower-arm transistors T24 to T26 are turned off, regardless of the U-, V-, and W-phase voltage commands Vu*, Vv*, and Vw.

[0020] Next, the current command setting process by the current command generator 61 will be described with reference to FIG. 3. In the current command setting process, the electronic control unit 50 first determines whether the drive mode is single-sided drive mode or double-sided drive mode (step S100). If it is determined that the drive mode is single-sided drive mode, the d-axis and q-axis current commands Id* and Iq* are set using the single-sided drive mode map (first current command map) and the torque command Tm* of the motor 24 (step S110), and the routine ends. On the other hand, if it is determined that the drive mode is double-sided drive mode, the d-axis and q-axis current commands Id* and Iq* are set using the double-sided drive mode map (second current command map) and the torque command Tm* of the motor 24 (step S120), and the routine ends.

[0021] Here, the single-sided drive mode map and the double-sided drive mode map are each determined in advance through experiments, analysis, or the like as the relationship between the torque command Tm* of the motor 24 and the d-axis and q-axis current commands Id*, Iq*. In the single-sided drive mode, the motor 24 is driven using a Y-connection, while in the double-sided drive mode, the motor 24 is driven using a Δ-connection, resulting in different characteristics of the motor 24. Based on this, in this embodiment, the single-sided drive mode map and the double-sided drive mode map are determined in advance as the relationship between the torque command Tm* and the d-axis and q-axis current commands Id*, Iq* so that the same torque is output for the same torque command Tm*. This makes it possible to prevent a torque step from occurring for the same torque command Tm* when switching between the single-sided drive mode and the double-sided drive mode.

[0022] In the drive unit 20 of the embodiment described above, in single-sided drive mode, the d-axis and q-axis current commands Id* and Iq* are set using the single-sided drive mode map and the torque command Tm* of the motor 24, and in double-sided drive mode, the d-axis and q-axis current commands Id* and Iq* are set using the double-sided drive mode map and the torque command Tm* of the motor 24. In this case, the single-sided drive mode map and the double-sided drive mode map each have a predetermined relationship between the torque command Tm* and the d-axis and q-axis current commands Id* and Iq* so that the same torque is output for the same torque command Tm*. This makes it possible to prevent a torque step from occurring when switching between the single-sided drive mode and the double-sided drive mode.

[0023] In the above-described embodiment, in the single-sided drive mode, the transistors T21 to T23 of the upper arm of the second inverter 32 are turned on and the transistors T24 to T26 of the lower arm are turned off. Alternatively, the transistors T24 to T26 of the lower arm of the second inverter 32 may be turned on and the transistors T21 to T23 of the upper arm may be turned off.

[0024] In the above-described embodiment, the battery 22 is used as the power storage device, but instead, a capacitor or the like may be used.

[0025] The correspondence between the main elements of the embodiment and the main elements of the invention described in the "Means for Solving the Problem" section will be explained below. In the embodiment, the battery 22 corresponds to the "power storage device," the motor 24 corresponds to the "motor," the first inverter 30 corresponds to the "first inverter," the second inverter 32 corresponds to the "second inverter," the switch 34 corresponds to the "switch," and the electronic control unit 50 corresponds to the "control device."

[0026] The correspondence between the main elements of the embodiments and the main elements of the invention described in the "Means for Solving the Problem" section does not limit the elements of the invention described in the "Means for Solving the Problem" section, since the embodiments are examples for specifically explaining the mode for implementing the invention described in the "Means for Solving the Problem" section. In other words, the interpretation of the invention described in the "Means for Solving the Problem" section should be based on the description in that section, and the embodiments are merely specific examples of the invention described in the "Means for Solving the Problem" section.

[0027] The above describes the forms for implementing the present disclosure using embodiments, but the present disclosure is not limited to these embodiments in any way, and it goes without saying that the present disclosure can be implemented in various forms within the scope that does not deviate from the gist of the present disclosure. [Industrial Applicability]

[0028] The present disclosure is applicable to industries such as the drive device manufacturing industry. [Explanation of symbols]

[0029] 20 drive device, 22 battery, 22i current sensor, 22v voltage sensor, 24 motor, 24a rotational position sensor, 24n negative power line, 24p positive power line, 24u, 24v, 24w current sensors, 26 capacitor, 26v voltage sensor, 30 first inverter, 32 second inverter, 34 switch, 50 electronic control unit, 61 current command generation unit, 62 coordinate conversion unit, 63 current control unit, 64 coordinate conversion unit, 65, 66 drive signal generation unit.

Claims

[Claim 1] a power storage device; a motor having three-phase open windings; a first inverter connected to a power line to which the power storage device is connected and connected to one end of the three-phase open winding, the first inverter having a plurality of first switching elements; a second inverter connected to the power line and to the other end of the three-phase open winding, the second inverter having a plurality of second switching elements; a switch attached to the power line between the first inverter and the second inverter; a control device that controls the first and second inverters based on d-axis and q-axis current commands that are based on a torque command of the motor, in a one-side drive mode in which only one of the first and second inverters is switched and driven, or in a two-side drive mode in which both the first and second inverters are switched and driven; A drive device comprising: the control device, in the one-side drive mode, sets current commands for the d-axis and q-axis using the torque command and a first current command map, and, in the two-side drive mode, sets current commands for the d-axis and q-axis using the torque command and a second current command map; The first and second current command maps are determined so that the same torque is output in response to the same torque command. Drive unit.

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