Synchronous machine control device, synchronous machine control method, and electric vehicle

Abstract

To perform stable current control in the vicinity of a voltage limit.SOLUTION: A synchronous machine control device is configured to drive and control a synchronous machine and includes: a current command operation unit configured to calculate difference between a current command value for the synchronous machine and an actual current flowing through the synchronous machine to generate a current command value by proportional-integral control; a voltage vector operation unit configured to generate a voltage command value composed of a coaxial voltage command value and an orthogonal axis voltage command value based on the current command value generated by the current command operation unit; a voltage limiting unit configured to limit the coaxial voltage command value in preference to the orthogonal axis voltage command value so that the voltage command value does not exceed a predetermined voltage limit value; and a correction amount calculation unit configured to calculate a current command value correction amount for correcting the current command value based on voltage limiting by the voltage limiting unit. The current command operation unit corrects the current command value by the proportional-integral control based on the current command value correction amount.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a synchronous machine control device, a synchronous machine control method, and an electric vehicle. [Background technology]

[0002] Due to the miniaturization of synchronous machines, such as synchronous motors, the speed of rotation of synchronous motors and the voltage utilization rate are increasing. This trend is particularly noticeable in electric vehicles, such as electric cars, where the weight of the synchronous motor affects the amount of power consumed. To achieve this improvement in the voltage utilization rate, a synchronous machine control device that controls a synchronous motor controls the inverter to use a high voltage up to the voltage limit value of the inverter. However, it is necessary to limit the voltage so that the voltage command value does not exceed the voltage limit value.

[0003] Conventional voltage limitations will be described with reference to FIGS. 1 and 2. FIG. 1 is a diagram showing voltage vectors in dq-axis coordinates. The voltage vector is divided into a coaxial voltage vector 215 acting on the coaxial axis (a composite component of a component 223 acting on the d-axis voltage from a d-axis current command and a component 224 acting on the q-axis voltage from a q-axis current command) and a quadrature-axis voltage vector 213 acting on the quadrature axis (a composite component of a component 222 acting on the q-axis voltage from a d-axis current command and a component 221 acting on the d-axis voltage from a q-axis current command). Voltage vector 211, which is a composite of coaxial voltage vector 215 and quadrature-axis voltage vector 213, is limited in amplitude without changing the direction (voltage phase angle) of voltage vector 211 so that the amplitude falls within voltage limit value 217, resulting in voltage vector 219. The orthogonal axis voltage vector 213 acting on the orthogonal axis suppresses interference between the d and q axes, but when the orthogonal axis voltage vector 213 is restricted, the interference components between the d and q axes cause oscillations of the fundamental frequency f0 in the d-axis current 201 and the q-axis current 203, as shown in the graph of the fundamental waves of the d-axis current and the q-axis current in Figure 2.

[0004] Patent Document 1 proposes a method of generating a second current command value so that the current detection value and the current command value match, and performing current control using an inverse model of the motor model including control. Patent Document 2 proposes a method of generating a second magnetic flux command value so that the magnetic flux estimation value and the magnetic flux command value match, and performing current control using an inverse model of the motor model including control. Non-Patent Document 1 proposes an algorithm for improving torque transient response. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-1730064 [Patent Document 2] Patent Publication No. 2021-151003 [Non-patent literature]

[0006] [Non-Patent Document 1] "A dynamic decoupling control scheme for high-speed operation of induction motors" IEEE Transactions on Industrial Electronics, Vol. 46, Iss. 1 (1999) Summary of the Invention [Problem to be solved by the invention]

[0007] Conventional control has the problem that it is not possible to perform stable current control near the voltage limit. [Means for solving the problem]

[0008] A synchronous machine control device according to the present invention is a synchronous machine control device that drives and controls a synchronous machine, and includes: a current command calculation unit that calculates a difference between a current command value for the synchronous machine and an actual current flowing through the synchronous machine to generate a current command value by proportional integral control; a voltage vector calculation unit that generates a voltage command value made up of a coaxial voltage command value and an orthogonal axis voltage command value based on the current command value generated by the current command calculation unit; a voltage limiting unit that limits the coaxial voltage command value in preference to the orthogonal axis voltage command value so that the voltage command value does not exceed a predetermined voltage limit value; and a correction amount calculation unit that calculates a current command value correction amount for correcting the current command value based on the voltage limit set by the voltage limiting unit, and the current command calculation unit corrects the current command value by the proportional integral control based on the current command value correction amount. a first magnetic flux command calculation unit that generates a first magnetic flux command value from a current command value for the synchronous machine; a magnetic flux estimation unit that obtains a magnetic flux estimation value from an actual current flowing through the synchronous machine; a second magnetic flux command calculation unit that calculates a difference between the first magnetic flux command value and the magnetic flux estimation value and generates a second magnetic flux command value by proportional integral control; a voltage vector calculation unit that generates voltage command values ​​including a coaxial voltage command value and an orthogonal axis voltage command value based on the second magnetic flux command value; a voltage limiting unit that limits the coaxial voltage command value in preference to the orthogonal axis voltage command value so that the voltage command value does not exceed a predetermined voltage limit value; and a correction amount calculation unit that calculates a magnetic flux command value correction amount for correcting the second magnetic flux command value based on the voltage limit set by the voltage limiting unit, and the second magnetic flux command calculation unit corrects the second magnetic flux command value by the proportional integral control based on the magnetic flux command value correction amount. A synchronous machine control method according to the present invention, in which a synchronous machine is controlled to drive, includes: calculating a difference between a current command value for the synchronous machine and an actual current flowing through the synchronous machine to generate a current command value by proportional-integral control; generating a voltage command value including a coaxial voltage command value and an orthogonal-axis voltage command value based on the generated current command value; limiting the coaxial voltage command value with priority over the orthogonal-axis voltage command value so that the voltage command value does not exceed a predetermined voltage limit value; calculating a current command value correction amount for correcting the current command value based on the limit; and correcting an integrator applied to the coaxial of the proportional-integral control based on the current command value correction amount equivalent to a coaxial component excess of the voltage excess that exceeds the voltage limit value due to the limit. [Effects of the Invention]

[0009] According to the present invention, stable current control can be achieved even near the voltage limit. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing voltage vectors in dq-axis coordinates in the background art. [Figure 2] 10 is a graph showing fundamental waves of a d-axis current and a q-axis current in the background art. [Figure 3] FIG. 1 is a block diagram of a synchronous machine control device according to a first embodiment. [Figure 4] FIG. 3 is a configuration diagram of a second dq-axis current command calculation unit in the first embodiment. [Figure 5] FIG. 3 is a configuration diagram of a voltage vector calculation unit in the first embodiment. [Figure 6] 4 is a diagram showing a voltage vector in dq-axis coordinates when the orthogonal axis voltage vector is equal to or less than a voltage limit value in the first embodiment. FIG. [Figure 7] 4 is a diagram showing a voltage vector in dq-axis coordinates when the orthogonal axis voltage vector is greater than a voltage limit value in the first embodiment. FIG. [Figure 8] FIG. 2 is a configuration diagram of a voltage limiting unit according to Example 1 of the first embodiment. [Figure 9]FIG. 10 is a configuration diagram of a voltage limiting unit according to Example 2 of the first embodiment. [Figure 10] FIG. 10 is a configuration diagram of a correction amount calculation unit in the second embodiment. [Figure 11] FIG. 10 is a block configuration diagram of a synchronous machine control device according to a second embodiment. [Figure 12] FIG. 10 is a configuration diagram of a second dq-axis magnetic flux command calculation unit in the second embodiment. [Figure 13] FIG. 10 is a configuration diagram of a voltage vector calculation unit in the second embodiment. [Figure 14] FIG. 10 is a configuration diagram of a correction amount calculation unit in the second embodiment. [Figure 15] FIG. 10 is a configuration diagram of an electric vehicle according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The following description and drawings are examples for explaining the present invention, and some omissions and simplifications have been made as appropriate for clarity of explanation. The present invention can be implemented in various other forms. Unless otherwise specified, each component may be singular or plural.

[0012] In the following explanation, we will use a permanent magnet synchronous motor as the synchronous machine. However, the effects of the present invention are not limited to permanent magnet synchronous motors, and similar effects can be obtained with synchronous machines such as synchronous reluctance motors, permanent magnet synchronous generators, and wound-rotor synchronous machines. Hereinafter, synchronous machines will be referred to as motors.

[0013] Furthermore, in the following description, the synchronous machine control devices 100, 100′ will be described as being configured with multiple blocks, but at least one or more of the block configurations may be realized by a program and a processor (e.g., a CPU, a GPU) that processes the program. The program is executed by the processor (e.g., a CPU, a GPU) to perform predetermined processing while appropriately using storage resources (e.g., a memory) and / or interface devices (e.g., a communication port), so the processor may be the entity that performs the processing. Similarly, the entity that executes the program and performs the processing may be a controller, device, system, computer, or node that has a processor. The entity that executes the program and performs the processing may be any processing unit, and may include a dedicated circuit (e.g., an FPGA or an ASIC) that performs specific processing.

[0014] A program may be installed on a device such as a computer from a program source. The program source may be, for example, a program distribution server or a computer-readable storage medium. If the program source is a program distribution server, the program distribution server may include a processor and storage resources for storing the program to be distributed, and the processor of the program distribution server may distribute the program to be distributed to other computers. Also, in the following description, two or more programs may be realized as one program, and one program may be realized as two or more programs.

[0015] [First embodiment] FIG. 3 is a block configuration diagram of a synchronous machine control device 100 according to the first embodiment of the present invention. The synchronous machine control device 100 drives the motor 1 by controlling the power converter 2. The power converter 2 is supplied with DC power from a DC voltage source 9 such as a battery. The synchronous machine control device 100 includes a phase current detector 3, a magnetic pole position detector 4, a frequency calculation unit 5, a current coordinate conversion unit 7, a second dq-axis current command calculation unit 24, a correction amount calculation unit 26, and a voltage limiting unit 28.

[0016] The power converter 2 constitutes an inverter, and converts DC power from a DC voltage source 9 such as a battery into AC power in accordance with a gate signal described later to drive the motor 1. The semiconductor switching elements that make up the inverter are IGBTs, MOSFETs, and other power semiconductor elements.

[0017] The phase current detector 3 is composed of a Hall CT (Current Transformer) or the like, and detects three-phase currents Iuc, Ivc, Iwc of U-phase, V-phase, and W-phase that flow from the power converter 2 to the motor 1 . The magnetic pole position detector 4 is made up of a resolver or the like, detects the magnetic pole position of the motor 1, and outputs magnetic pole position information θ*.

[0018] The frequency calculation unit 5 outputs speed information ω1* from the magnetic pole position information θ* detected by the magnetic pole position detector 4, for example, by a differential calculation. The current coordinate conversion unit 7 converts the currents Iuc, Ivc, and Iwc detected by the phase current detector 3 into coordinates using the magnetic pole position information θ* detected by the magnetic pole position detector 4, and outputs them as the d-axis current detection value Idc and the q-axis current detection value Iqc.

[0019] The second dq-axis current command calculation unit 24 outputs a second d-axis current command value Id** and a second q-axis current command value Iq** by proportional-integral control so that the d-axis current command value Id* and the d-axis current detection value Idc coincide with each other and so that the q-axis current command value Iq* and the q-axis current detection value Iqc coincide with each other. That is, the second dq-axis current command calculation unit 24 calculates the difference between the current command value for the motor 1 and the actual current flowing through the motor 1 and generates a current command value by proportional-integral control. However, as will be described in detail later, the integral term of the proportional-integral control is corrected by current command value correction amounts dId, dIq, dId2, and dIq2 calculated by a correction amount calculation unit 26.

[0020] Based on the second d-axis current command value Id**, the second q-axis current command value Iq**, and the speed information ω1*, the voltage vector calculation unit 18 outputs the d-axis voltage command value Vd*, the q-axis voltage command value Vq*, the d-axis coaxial voltage command value Vds*, the q-axis coaxial voltage command value Vqs*, the d-axis orthogonal-axis voltage command value Vdx*, and the q-axis orthogonal-axis voltage command value Vqx* to the voltage limiting unit 28. The voltage vector calculation unit 18 also outputs the d-axis coaxial voltage command value Vds*, the q-axis coaxial voltage command value Vqs*, the d-axis orthogonal-axis voltage command value Vdx*, and the q-axis orthogonal-axis voltage command value Vqx* to the correction amount calculation unit 26. That is, the voltage vector calculation unit 18 generates the coaxial voltage command values ​​and the orthogonal-axis voltage command values ​​based on the current command values ​​generated by the second dq-axis current command calculation unit 24. Details will be described later.

[0021] The voltage limiting unit 28 receives the d-axis voltage command value Vd*, the q-axis voltage command value Vq*, the d-axis coaxial voltage command value Vds*, the q-axis coaxial voltage command value Vqs*, the d-axis orthogonal-axis voltage command value Vdx*, the q-axis orthogonal-axis voltage command value Vqx*, and the DC voltage information Vdc from the DC voltage detector 6, and limits the voltage of the d-axis voltage command value Vd* and the q-axis voltage command value Vq*. Then, the voltage limiting unit 28 outputs the d-axis voltage command value Vdsl* and the q-axis voltage command value Vql* to the coordinate conversion unit 11. The voltage-limited d-axis coaxial voltage Vdsl*, the voltage-limited q-axis coaxial voltage Vqsl*, the d-axis orthogonal-axis voltage Vdxl*, and the q-axis orthogonal-axis voltage Vqxl* are output to the correction amount calculation unit 26. The voltage limiting unit 28 limits the coaxial voltage command value with priority over the orthogonal-axis voltage command value so that the voltage command value does not exceed a predetermined voltage limit value. The voltage limiting unit 28 will be described in detail later.

[0022] The correction amount calculation unit 26 receives the d-axis coaxial voltage command value Vds*, the q-axis coaxial voltage command value Vqs*, the d-axis orthogonal-axis voltage command value Vdx*, and the q-axis orthogonal-axis voltage command value Vqx* from the voltage vector calculation unit 18, and receives the d-axis coaxial voltage Vdsl*, the q-axis coaxial voltage Vqsl*, the d-axis orthogonal-axis voltage Vdxl*, and the q-axis orthogonal-axis voltage Vqxl* from the voltage limiting unit 28. Then, the second dq-axis current command calculation unit 24 calculates current command value correction amounts dId, dIq, dId2, and dIq2 to realize anti-windup control. That is, the correction amount calculation unit 26 calculates the current command value correction amounts for correcting the current command value based on the limitation by the voltage limiting unit 28. This will be described in detail later.

[0023] The coordinate conversion unit 11 converts the d-axis voltage command value Vdl* and the q-axis voltage command value Vql* output by the voltage limiting unit 28 into coordinates using magnetic pole position information θ* detected by the magnetic pole position detector 4, and outputs three-phase voltage command values ​​Vu*, Vv*, and Vw*. The PWM controller 12 uses the three-phase voltage command values ​​Vu*, Vv*, and Vw* and DC voltage information Vdc of the DC voltage source 9 detected by the DC voltage detector 6 to perform, for example, triangular wave comparison, and outputs a gate signal to the power converter 2.

[0024] FIG. 4 is a configuration diagram of the second dq-axis current command calculation unit 24. The second dq-axis current command calculation unit 24 includes a proportional-integral control unit 50 to which the d-axis current command value Id* is input, and a proportional-integral control unit 60 to which the q-axis current command value Iq* is input.

[0025] The proportional-plus-integral control unit 50 of the second dq-axis current command calculation unit 24 corrects the d-axis current command value Id* by proportional-plus-integral control based on the current command value correction amounts dId and dId2, and outputs a second d-axis current command value Id**. Specifically, a subtractor 51 subtracts the d-axis current detection value Idc from the d-axis current command value Id*. The result is input to one end of an adder 59 via a proportional control gain 57. Further, a subtractor 52 subtracts the current command value correction amount dId from the result of the subtraction by the subtractor 51 from the output of an integral control gain 55, and the result is input to an integrator 53. The integrator 53 subtracts the current command value correction amount dId2 from the integrator 53, and inputs the result to the other end of the adder 59. The addition result by the adder 59 is output as the second d-axis current command value Id**.

[0026] The proportional-plus-integral control unit 60 of the second dq-axis current command calculation unit 24 corrects the q-axis current command value Iq* by proportional-plus-integral control based on the current command value correction amounts dIq and dIq2, and outputs a second d-axis current command value Iq**. Specifically, a subtractor 61 subtracts the q-axis current detection value Iqc from the q-axis current command value Iq*. The result is input to one input of an adder 69 via a proportional control gain 67. Further, a subtractor 62 subtracts the current command value correction amount dIq from the result of the subtraction by the subtractor 61 from the output of an integral control gain 65, and the result is input to an integrator 63. The integrator 63 subtracts the current command value correction amount dIq2 from the integrator 63, and inputs the result to the other input of the adder 59. The output result of the adder 59 is output as the second d-axis current command value Iq**.

[0027] FIG. 5 is a diagram showing the configuration of the voltage vector calculation unit 18. The voltage vector calculation unit 18 is configured based on the inverse model of the motor model shown in equation (1).

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[0028] As shown in FIG. 5 , the voltage vector calculation unit 18 receives the second d-axis current command value Id**, the second q-axis current command value Iq**, and the speed information ω1* as input, and outputs the d-axis voltage command value Vd*, the q-axis voltage command value Vq*, the d-axis coaxial voltage command value Vds*, the q-axis coaxial voltage command value Vqs*, the d-axis orthogonal axis voltage command value Vdx*, and the q-axis orthogonal axis voltage command value Vqx*.

[0029] 5, the multiplication result of the second d-axis current command value Id** and the winding resistance 46 is input to one input of an adder 47. The multiplication result 45 of the second d-axis current command value Id** and the differential operator s × d-axis inductance Ld is input to the other input of the adder 47. The addition result of the two input to the adder 47 is output as a d-axis coaxial voltage command value Vds* and is also input to one input of an adder 49.

[0030] The multiplication result of the second q-axis current command value Iq** and the winding resistance 36 is input to one input of an adder 37. The multiplication result 35 of the second q-axis current command value Iq** and (differential operator s) × (q-axis inductance Lq) is input to the other input of the adder 37. The addition result of the two input to the adder 37 is output as a q-axis coaxial voltage command value Vqs*, and is also input to one input of an adder 39.

[0031] Furthermore, a multiplication result 44 of the second d-axis current command value Id** and the d-axis inductance Ld is input to one input of a multiplier 38, and is multiplied by the speed information ω1* input to the other input. This multiplication result is added to the speed information ω1*×speed electromotive force coefficient Ke in an adder 33, and is output as a q-axis orthogonal axis voltage command value Vqx*. This q-axis orthogonal axis voltage command value Vqx* is added to a q-axis coaxial voltage command value Vqs* in an adder 39, and is output as a q-axis voltage command value Vq*.

[0032] A multiplication result 34 of the second q-axis current command value Iq** and the negative q-axis inductance Lq is input to one input of a multiplier 48, and is multiplied by the speed information ω1* input to the other input. This multiplication result is output as a d-axis orthogonal-axis voltage command value Vdx*. This d-axis orthogonal-axis voltage command value Vdx* is added to the d-axis coaxial voltage command value Vds* by an adder 49, and the result is output as a d-axis voltage command value Vd*.

[0033] 6 is a diagram showing voltage vectors in dq-axis coordinates in this embodiment. This diagram shows the case where the orthogonal axis voltage vector (orthogonal component) is equal to or less than the voltage limit value. The voltage vector is divided into a coaxial voltage vector (coaxial component) 215 acting on the coaxial axis and an orthogonal axis voltage vector (orthogonal component) 213 acting on the orthogonal axis.

[0034] As shown in Fig. 6, voltage limiting unit 28 limits coaxial voltage vector (coaxial component) 215 with priority given to orthogonal axis voltage vector (orthogonal component) 213, so that the amplitude of voltage vector 211, which is a combination of coaxial voltage vector 215 and orthogonal axis voltage vector 213, falls within voltage limit value 217. As a result, coaxial voltage vector (coaxial component) 215 is limited to coaxial voltage vector (coaxial component) 215A. As a result, voltage vector 211 becomes voltage vector 211A, which falls within voltage limit value 217. Because the orthogonal component corresponds to a decoupling term, maintaining the orthogonal component makes it possible to suppress vibration of the fundamental frequency due to inter-axis interference of motor 1.

[0035] 7 is a diagram showing voltage vectors in dq-axis coordinates in this embodiment, illustrating a case where the orthogonal axis voltage vector (orthogonal component) is greater than the voltage limit value. 7, when orthogonal component 213 is larger than voltage limit value 217, the amplitude is reduced to orthogonal component 213B while maintaining the direction of orthogonal component 213. Then, with respect to voltage vector 211, orthogonal axis voltage vector (orthogonal component) 213B is given priority, and coaxial voltage vector (coaxial component) 215 is limited to coaxial voltage vector (coaxial component) 215B so that the amplitude falls within voltage limit value 217. This makes it possible to reduce the non-interference component.

[0036] Fig. 8 is a configuration diagram of the voltage limiting unit 28 according to Example 1. Example 1 is applied under the condition that the orthogonal axis voltage vector (orthogonal component) shown in Fig. 6 is equal to or less than the voltage limit value. If the motor 1 always satisfies this condition, the configuration shown in Example 1 can be adopted.

[0037] In FIG. 6, if the amplitude of voltage vector 211A after voltage limiting is Vlim, the following equation (2) holds.

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[0038] Here, using the amplitude Vx and phase angle θx of the orthogonal axis voltage vector 213 and the amplitude Vsl and phase angle θs of the coaxial voltage vector 215A after voltage limitation (however, since the phase angle θs of the coaxial voltage vector 215 and the phase angle θsl of the coaxial voltage vector 215A are equivalent, they are expressed as θs instead of θsl), equation (2) becomes equation (3).

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[0039] Transforming equation (3) gives equation (4).

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[0040] The voltage limiting unit 28 shown in FIG. 8 performs the voltage limiting shown in FIG. 6 based on equation (5). First, amplitude / phase angle calculation unit 75 calculates amplitude Vx and phase angle θx of orthogonal axis voltage vector 213. Furthermore, amplitude / phase angle calculation unit 76 calculates phase angle θs of coaxial voltage vector 215.

[0041] The amplitude / phase angle calculation unit 75 calculates the amplitude Vx of the orthogonal axis voltage vector 213 using equation (6) based on the input d-axis orthogonal axis voltage command value Vdx* and q-axis orthogonal axis voltage command value Vqx*.

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[0042] The amplitude / phase angle calculation unit 75 calculates the phase angle θx of the orthogonal axis voltage vector 213 using equation (7) based on the input d-axis orthogonal axis voltage command value Vdx* and q-axis orthogonal axis voltage command value Vqx*.

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[0043] The amplitude / phase angle calculation unit 76 calculates the phase angle θs of the coaxial voltage vector 215 using equation (8) based on the input d-axis coaxial voltage command value Vds* and q-axis coaxial voltage command value Vqs*.

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[0044] The limit value calculation unit 82 calculates the voltage limit value Vlim based on the inverter DC voltage Vdc using equation (9).

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[0045] The voltage limit value Vlim is not based on equation (9), but is set to the voltage to be limited, for example, by adding a margin of several percent to the value of equation (9) or by increasing it by several percent to use the overmodulation region.

[0046] Based on Vx, θx, θs, and Vlim calculated using equations (6) to (9), the amplitude Vsl of coaxial voltage vector 215A is calculated using the following circuit that realizes equation (5). The circuit that realizes equation (5) is shown in FIG. 8 and includes a subtractor 83, a sine wave generator 91, a cosine wave generator 92, multipliers 95 and 96, a square-difference-square-root calculator 85, and a subtractor 87. The subtractor 83 calculates θx-θs and outputs the result to the sine wave generator 91 and the cosine wave generator 92. The multiplier 95 multiplies the output of the sine wave generator 91 by Vx and outputs the result to the square-difference-square-root calculator 85. The square-difference-square-root calculator 85 calculates the square-difference of squares and outputs the result to the subtractor 87. The multiplier 96 multiplies the output of the cosine wave generator 92 by Vx and outputs the result to the subtractor 87. The subtractor 87 subtracts the result of the calculation by the subtractor 87 from the result of the calculation by the square-difference-square-root calculator 85 to obtain Vsl shown in equation (5).

[0047] Furthermore, a multiplier 88 multiplies Vsl by the calculation result of the cosine wave generator 93 to calculate a d-axis coaxial voltage Vdsl* after voltage limitation. A multiplier 89 multiplies Vsl by the calculation result of the sine wave generator 94 to calculate a q-axis coaxial voltage Vqsl* after voltage limitation.

[0048] An adder 97 adds Vdx* to Vdsl* to calculate a d-axis voltage command value Vdl0* after voltage limitation. An adder 98 adds Vqx* to Vqsl* to calculate a q-axis voltage command value Vql0* after voltage limitation.

[0049] Finally, when the voltage amplitude is equal to or smaller than the voltage limit value Vlim, the voltage selection unit 99 outputs Vd* and Vq* as they are as the d-axis voltage command value Vdl* and the q-axis voltage command value Vql*, and when the voltage amplitude is greater than the voltage limit value Vlim, the voltage selection unit 99 outputs the limited values ​​Vdl0 and Vql0 as the d-axis voltage command value Vdl* and the q-axis voltage command value Vql*. The voltage-limited d-axis coaxial voltage Vdsl* and the voltage-limited q-axis coaxial voltage Vqsl* are output to the correction amount calculation unit 26.

[0050] Fig. 9 is a configuration diagram of the voltage limiting unit 28 according to Example 2. Example 2 is a configuration that can be applied even under conditions where the orthogonal axis voltage vector (orthogonal component) shown in Fig. 7 is greater than the voltage limit. The same reference numerals are used to designate the same parts as in Example 1 shown in Fig. 8, and the description will be simplified.

[0051] As shown in Fig. 7, resultant vector 213B after voltage limitation is limited only in amplitude in the same direction (same voltage phase angle) as orthogonal axis voltage vector 213. Therefore, limiting unit 77 limits Vx to Vlim and outputs Vxl. Square-root difference calculation unit 85 calculates Vsl using Vxl instead of Vx in equation (5) and outputs the result to subtractor 87. When Vsl is calculated using Vxl instead of Vx in equation (5), Vsl is always 0.

[0052] Furthermore, the phase angle θx of the orthogonal axis voltage vector 213 is input to the cosine wave generator 78. The multiplier 80 multiplies the output of the cosine wave generator 78 by the limited Vxl and outputs the result as the d-axis orthogonal axis voltage Vdxl*. The phase angle θx of the orthogonal axis voltage vector 213 is input to the sine wave generator 79. The multiplier 81 multiplies the output of the sine wave generator 79 by the limited Vxl and outputs the result as the q-axis orthogonal axis voltage Vqxl*.

[0053] An adder 97 adds Vdxl* to Vdsl* to calculate a d-axis voltage command value Vdl0* after voltage limitation. An adder 98 adds Vqxl* to Vqsl* to calculate a q-axis voltage command value Vql0* after voltage limitation.

[0054] Finally, when the voltage amplitude is equal to or less than the voltage limit value Vlim, the voltage selection unit 99 outputs Vd* and Vq* as they are as the d-axis voltage command value Vdl* and the q-axis voltage command value Vql*. When the voltage amplitude is greater than the voltage limit value Vlim, the voltage selection unit 99 outputs the limited values ​​Vdl0* and Vql0* as the d-axis voltage command value Vdl* and the q-axis voltage command value Vql*. The voltage-limited d-axis coaxial voltage Vdsl*, the voltage-limited q-axis coaxial voltage Vqsl*, the d-axis orthogonal-axis voltage Vdxl*, and the q-axis orthogonal-axis voltage Vqxl* are output to the correction amount calculation unit 26. As a result, the voltage limiting unit 28 of Example 2 shown in FIG. 9 can be applied even when the orthogonal-axis voltage vector (orthogonal component) shown in FIG. 7 is greater than the voltage limit and when the orthogonal-axis voltage vector (orthogonal component) shown in FIG. 6 is equal to or less than the voltage limit value Vlim.

[0055] 10 is a configuration diagram of the correction amount calculation unit 26. This correction amount calculation unit 26 is connected to the voltage limiting unit 28 of Example 2 shown in FIG. 10 , a subtractor 251 subtracts the d-axis coaxial voltage Vdsl* output from the voltage limiting unit 28 from the d-axis coaxial voltage command value Vds* output from the voltage vector calculation unit 18. This is the voltage excess amount that exceeds the voltage limit value Vlim. The result of this subtraction is divided by the d-axis inductance Ld using a gain 261, and output as a current command value correction amount dId to the second dq-axis current command calculation unit 24. Furthermore, a subtractor 253 subtracts the q-axis coaxial voltage Vqsl* output from the voltage limiting unit 28 from the q-axis coaxial voltage command value Vqs* output from the voltage vector calculation unit 18. The result of this subtraction is divided by the q-axis inductance Lq using a gain 263, and output as a current command value correction amount dIq to the second dq-axis current command calculation unit 24. The current command value correction amounts dId and dIq represent the voltage excess amounts that are the dq-axis coaxial voltages that are limited by the voltage limit and that exceed the voltage limit values.

[0056] When this correction amount calculation unit 26 is connected to the voltage limiting unit 28 of Example 1 shown in Fig. 8, the correction amount calculation unit 26 may be configured to output the current command value correction amounts dId and dIq described above. This case will be described below.

[0057] The coaxial component of the voltage vector is a voltage that primarily changes the current, and if it is limited, the current will not change. The integrators 53, 63 in the proportional-plus-integral control units 50, 60 of the second dq-axis current command calculation unit 24 shown in FIG. 4 operate assuming that the current changes with integral gain KI. Therefore, if the voltage is limited, a difference will occur between the second current command value and the current. To prevent this, subtractors 52, 62 subtract the amount of current that does not change due to the limited voltage change, i.e., the current command value correction amounts dId, dIq. Specifically, the second dq-axis current command calculation unit 24 corrects the integrator 53 applied to the coaxial component of the proportional-plus-integral control based on the current command value correction amount dId, which corresponds to the coaxial component of the voltage excess that exceeds the voltage limit value Vlim due to the voltage limit. Furthermore, the second dq-axis current command calculation unit 24 corrects the integrator 63 applied to the orthogonal axis of the proportional-plus-integral control based on the current command value correction amount dIq corresponding to the excess of the orthogonal axis component of the voltage exceeding the voltage limit value Vlim due to the voltage limit. This makes it possible to prevent a difference between the second current command value and the current due to the voltage limit value Vlim.

[0058] Returning to the explanation of FIG. 10 , subtractor 255 subtracts the d-axis orthogonal-axis voltage Vdxl* output from voltage limiting unit 28 from the d-axis orthogonal-axis voltage command value Vdx* output from voltage vector calculation unit 18. The result of this subtraction is input to one input of adder 259. The other input of adder 259 is the subtraction result of subtracting the d-axis coaxial voltage Vdsl* from the d-axis coaxial voltage command value Vds*. The two results are then added together in adder 259. The result of this addition is divided by the q-axis inductance Lq using gain 265, and then divided by divider 271 using speed information ω1*, the sign of which is inverted by gain 275, and output as current command value correction amount dIq2. Since the sign of dIq2 is reversed, the sign is inverted by gain 275. As a result, current command value correction amount dIq2 corresponding to the voltage excess in the coaxial direction of the d-axis out of the voltage excess that exceeds the voltage limit value is obtained.

[0059] Furthermore, a subtractor 257 subtracts the q-axis orthogonal axis voltage Vqxl* output from the voltage limiting unit 28 from the q-axis orthogonal axis voltage command value Vqx* output from the voltage vector calculation unit 18. The result of this subtraction is divided by the d-axis inductance Ld using a gain 267, and is further divided by a divider 273 using the speed information ω1*, and the result is output as a current command value correction amount dId2.

[0060] As shown in FIG. 7, the correction amount calculation unit 26 connected to the voltage limiting unit 28 of Example 2 shown in FIG. 9 must reduce the orthogonal-axis component when the orthogonal-axis component exceeds the voltage limit value. However, simply reducing the amplitude while maintaining the direction of the orthogonal-axis component will result in ineffective current control. When the orthogonal-axis component reaches the voltage limit value, a flux-weakening current must be applied to reduce the voltage vector, so proportional-plus-integral control on the d-axis side must be maintained. The value obtained by subtracting the d-axis coaxial voltage Vdsl* from the d-axis coaxial voltage command value Vds* by the subtractor 251 is the voltage excess amount that exceeds the voltage limit value in the coaxial direction of the d axis. In other words, the current command value correction amount dId2 includes this excess amount of the d-axis coaxial component. The proportional-plus-integral control unit 60 of the second dq-axis current command calculation unit 24 shown in FIG. 4 subtracts the current command value correction amount dIq2 from the integrator 63. That is, the second dq-axis current command calculation unit 24 corrects the integrator 63 applied to the q-axis based on the current command value correction amount corresponding to the voltage excess in the coaxial direction of the d-axis out of the voltage excess.

[0061] This allows the second dq-axis current command calculation unit 24 to take into account the coaxial component on the d-axis side, providing a margin for maintaining d-axis current control. As shown in Figure 7, the orthogonal axis component exceeds the voltage limit value when the speed of the motor 1 increases suddenly or the voltage of the DC voltage source 9 decreases suddenly, specifically when the speed increases suddenly due to idling, as in the case of an electric vehicle or other electric vehicle. In this way, even when the orthogonal axis component exceeds the voltage limit value, flux-weakening control is activated, preventing current control from becoming ineffective.

[0062] According to this embodiment, when the voltage command value based on the current command value is limited, stable current control can be achieved even when the voltage is close to the voltage limit.

[0063] [Second embodiment] Fig. 11 is a block diagram of a synchronous machine control device 100' according to a second embodiment of the present invention. In the first embodiment, an example in which a voltage command value based on a current command value is limited was described, but in the second embodiment, an example in which a voltage command value based on a magnetic flux command value is described. The same components as those in the synchronous machine control device 100 according to the first embodiment shown in Fig. 3 are assigned the same reference numerals, and their description will be simplified.

[0064] As shown in FIG. 11, the synchronous machine control device 100′ includes a power converter 2, a phase current detector 3, a magnetic pole position detector 4, a frequency calculation unit 5, a current coordinate conversion unit 7, a first dq-axis magnetic flux command calculation unit 21, a dq-axis magnetic flux estimation unit 23, a second dq-axis magnetic flux command calculation unit 25, a correction amount calculation unit 27, and a voltage limiting unit 28.

[0065] The dq-axis magnetic flux estimation unit 23 estimates a d-axis magnetic flux estimated value φd and a q-axis magnetic flux estimated value φq by referring to, for example, a look-up table using the d-axis detected value Idc and the q-axis detected value Iqc output from the current coordinate conversion unit 7. The first dq-axis magnetic flux command calculation unit 21 outputs a first d-axis magnetic flux command value φd* and a first q-axis magnetic flux command value φq* by referring to, for example, a look-up table using the d-axis current command value Id* and the q-axis current command value Iq*.

[0066] The second dq-axis magnetic flux command calculation unit 25 outputs a second d-axis magnetic flux command value φd** and a second q-axis magnetic flux command value φq** by proportional-plus-integral control so that the first d-axis magnetic flux command value φd* and the first q-axis magnetic flux command value φq* match the d-axis magnetic flux estimated value φd and the q-axis magnetic flux estimated value φq. Furthermore, the second dq-axis magnetic flux command calculation unit 25 receives magnetic flux command correction amounts dφd, dφq, dφd2, and dφq2 from a correction amount calculation unit 27 and uses them for anti-windup control. Details will be described later.

[0067] Based on the second d-axis magnetic flux command value φd**, the second q-axis magnetic flux command value φq**, and the speed information ω1*, the voltage vector calculation unit 19 outputs the d-axis voltage command value Vd*, the q-axis voltage command value Vq*, the d-axis coaxial voltage command value Vds*, the q-axis coaxial voltage command value Vqs*, the d-axis orthogonal-axis voltage command value Vdx*, and the q-axis orthogonal-axis voltage command value Vqx* to the voltage limiting unit 28. In addition, the voltage vector calculation unit 19 outputs the d-axis coaxial voltage command value Vds*, the q-axis coaxial voltage command value Vqs*, the d-axis orthogonal-axis voltage command value Vdx*, and the q-axis orthogonal-axis voltage command value Vqx* to the correction amount calculation unit 27. That is, the voltage vector calculation unit 19 generates the coaxial voltage command value and the orthogonal-axis voltage command value based on the second magnetic flux command value generated in the second dq-axis magnetic flux command calculation unit 25.

[0068] The voltage limiting unit 28 receives the q-axis voltage command value Vd*, the q-axis voltage command value Vq*, the d-axis coaxial voltage command value Vds*, the q-axis coaxial voltage command value Vqs*, the d-axis orthogonal-axis voltage command value Vdx*, the q-axis orthogonal-axis voltage command value Vqx*, and the DC voltage information Vdc from the DC voltage detector 6, and limits the voltage of the q-axis voltage command value Vd* and the q-axis voltage command value Vq*. Then, the voltage limiting unit 28 outputs the d-axis voltage command value Vdsl* and the q-axis voltage command value Vql* to the coordinate conversion unit 11. The voltage-limited d-axis coaxial voltage Vdsl*, the voltage-limited q-axis coaxial voltage Vqsl*, the d-axis orthogonal-axis voltage Vdxl*, and the q-axis orthogonal-axis voltage Vqxl* are output to the correction amount calculation unit 27. The voltage limiting unit 28 limits the coaxial voltage command value with priority over the orthogonal-axis voltage command value so that the voltage command value does not exceed a predetermined voltage limit value. The detailed configuration of this voltage limiting unit 28 is the same as that shown in FIGS. 9 and 10, and therefore is not shown.

[0069] The correction amount calculation unit 27 receives the d-axis coaxial voltage command value Vds*, the q-axis coaxial voltage command value Vqs*, the d-axis orthogonal-axis voltage command value Vdx*, and the q-axis orthogonal-axis voltage command value Vqx* from the voltage vector calculation unit 19, and receives the d-axis coaxial voltage Vdsl*, the q-axis coaxial voltage Vqsl*, the d-axis orthogonal-axis voltage Vdxl*, and the q-axis orthogonal-axis voltage Vqxl* from the voltage limiting unit 28. Then, the second dq-axis magnetic flux command calculation unit 25 calculates magnetic flux command value correction amounts dφd, dφq, dφd2, and dφq2 for realizing anti-windup control. That is, the correction amount calculation unit 27 calculates the magnetic flux command value correction amount for correcting the magnetic flux command value based on the limitation by the voltage limiting unit 28. This will be described in detail later.

[0070] The coordinate conversion unit 11 converts the d-axis voltage command value Vdl* and the q-axis voltage command value Vql* output by the voltage limiting unit 28 into coordinates using magnetic pole position information θ* detected by the magnetic pole position detector 4, and outputs three-phase voltage command values ​​Vu*, Vv*, and Vw*. The PWM controller 12 uses the three-phase voltage command values ​​Vu*, Vv*, and Vw* and DC voltage information Vdc of the DC voltage source 9 detected by the DC voltage detector 6 to perform, for example, triangular wave comparison, and outputs a gate signal to the power converter 2.

[0071] FIG. 12 is a configuration diagram of the second dq-axis magnetic flux command calculation unit 25. The second dq-axis magnetic flux command calculation unit 25 includes a proportional integral control unit 50' to which the first d-axis magnetic flux command value φd* is input, and a proportional integral control unit 60' to which the first q-axis magnetic flux command value φq* is input.

[0072] The proportional-plus-integral control unit 50' of the second dq-axis magnetic flux command calculation unit 25 corrects the first d-axis magnetic flux command value φd* by proportional-plus-integral control based on the magnetic flux command value correction amounts dφd and dφd2, and outputs a second d-axis magnetic flux command value φd**. Specifically, a subtractor 151 subtracts the d-axis magnetic flux estimated value φd from the first d-axis magnetic flux command value φd*. The result is input to one input of an adder 159 via a proportional control gain 157. Further, a subtractor 152 subtracts the magnetic flux command value correction amount dφd from the result of the subtraction by the subtractor 151 from the output of an integral control gain 155, and the result is input to an integrator 153. The integrator 153 subtracts the magnetic flux command value correction amount dφd2 from the integrator 153, and inputs the result to the other input of the adder 159. The sum of the adder 159 is output as the second d-axis magnetic flux command value φd**.

[0073] The proportional-plus-integral control unit 60' of the second dq-axis magnetic flux command calculation unit 25 corrects the first q-axis magnetic flux command value φq* by proportional-plus-integral control based on the magnetic flux command value correction amounts dφq and dφq2, and outputs a second q-axis magnetic flux command value φq**. Specifically, a subtractor 161 subtracts the q-axis magnetic flux estimated value φq from the first q-axis magnetic flux command value φq*. The result is input to one input of an adder 169 via a proportional control gain 167. Further, a subtractor 162 subtracts the magnetic flux command value correction amount dφq from the result of the subtraction by the subtractor 161 from the output of an integral control gain 165, and the result is input to an integrator 163. The integrator 163 subtracts the magnetic flux command value correction amount dφq2 from the integrator 163, and inputs the result to the other input of the adder 169. The addition result of the adder 169 is output as a second q-axis magnetic flux command value φq**.

[0074] FIG. 13 is a diagram showing the configuration of the voltage vector calculation unit 19. The voltage vector calculation unit 19 is configured based on the inverse model of the motor model shown in equation (10).

number

[0075] As shown in FIG. 13, the voltage vector calculation unit 19 receives as input a second d-axis magnetic flux command value φd**, a second q-axis magnetic flux command value φq**, and speed information ω1*, and outputs a d-axis voltage command value Vd*, a q-axis voltage command value Vq*, a d-axis coaxial voltage command value Vds*, a q-axis coaxial voltage command value Vqs*, a d-axis orthogonal axis voltage command value Vdx*, and a q-axis orthogonal axis voltage command value Vqx*.

[0076] 13, the second d-axis magnetic flux command value φd** is multiplied by a differential operator s and input to one input of an adder 147. Furthermore, a speed electromotive force coefficient Ke is subtracted from the second d-axis magnetic flux command value φd** by a subtractor 144, and the result is multiplied by a value obtained by dividing the winding resistance R by the d-axis inductance Ld and input to the other input of the adder 147. The addition result by the adder 147 is output as a d-axis coaxial voltage command value Vds*. Furthermore, the second d-axis magnetic flux command value φd** is multiplied by speed information ω1* by a multiplier 138, and the result is output as a q-axis orthogonal axis voltage command value Vqx*.

[0077] The second q-axis magnetic flux command value φq** is multiplied by a differential operator s and input to one input of an adder 137. The second q-axis magnetic flux command value φq** is also multiplied by a value obtained by dividing the winding resistance R by the q-axis inductance Lq and input to the other input of the adder 137. The addition result by the adder 137 is output as a q-axis coaxial voltage command value Vqs*. Furthermore, the second q-axis magnetic flux command value φq** is multiplied by speed information ω1* by a multiplier 148, and the result is output as a d-axis orthogonal axis voltage command value Vdx*.

[0078] The d-axis coaxial voltage command value Vds* is subtracted from the d-axis orthogonal axis voltage command value Vdx* by a subtractor 149, and the result is output as a d-axis voltage command value Vd*. The q-axis coaxial voltage command value Vqs* is added to the q-axis orthogonal axis voltage command value Vqx* by an adder 139, and the result is output as a q-axis voltage command value Vq*.

[0079] 14 is a configuration diagram of the correction amount calculation unit 27. This correction amount calculation unit 27 is connected to the voltage limiting unit 28 of Example 2 shown in FIG.

[0080] 14, a subtractor 251 subtracts the d-axis coaxial voltage Vdsl* output from the voltage limiting unit 28 from the d-axis coaxial voltage command value Vds* output from the voltage vector calculation unit 19. This is a voltage excess amount that exceeds the voltage limit value Vlim. The result of this subtraction is output to the second dq-axis magnetic flux command calculation unit 25 as a flux command value correction amount dφd. Furthermore, a subtractor 253 subtracts the q-axis coaxial voltage Vqsl* output from the voltage limiting unit 28 from the q-axis coaxial voltage command value Vqs* output from the voltage vector calculation unit 19. The result of this subtraction is output to the second dq-axis magnetic flux command calculation unit 25 as a flux command value correction amount dφq. The flux command value correction amounts dφd and dφq represent voltage excess amounts that exceed the voltage limit values ​​when the dq-axis coaxial voltages are limited by the voltage limit.

[0081] When this correction amount calculation unit 27 is connected to the voltage limiting unit 28 of Example 1 shown in Fig. 8, the correction amount calculation unit 27 may be configured to output the magnetic flux command value correction amounts dφd and dφq described above. This case will be described below.

[0082] The coaxial component of the voltage vector is a voltage that primarily changes the magnetic flux. If this voltage is limited, the magnetic flux will not change. The integrators 153, 163 in the proportional-plus-integral control units 50', 60' of the second dq-axis magnetic flux command calculation unit 25 shown in FIG. 12 operate assuming that the magnetic flux changes with integral gain KI. Therefore, if the voltage is limited, a difference will occur between the second magnetic flux command value and the magnetic flux. To prevent this, subtractors 152, 162 subtract the amount of magnetic flux that does not change due to the limited voltage change, i.e., the magnetic flux command value correction amounts dφd, dφq. This prevents a difference from occurring between the second magnetic flux command value and the magnetic flux due to the voltage limit value Vlim. In other words, the second dq-axis magnetic flux command calculation unit 25 corrects the integrator 152 applied to the coaxial axis of the proportional-plus-integral control based on the magnetic flux command value correction amount dφd, which corresponds to the amount of the coaxial component of the voltage excess that exceeds the voltage limit value due to the voltage limit. Furthermore, the second dq-axis magnetic flux command calculation unit 25 corrects the integrator 162 applied to the orthogonal axis of the proportional-plus-integral control based on the magnetic flux command value correction amount dφq corresponding to the excess of the orthogonal axis component of the voltage exceeding the voltage limit value due to the voltage limit. This makes it possible to prevent a difference between the second magnetic flux command value and the magnetic flux from occurring due to the voltage limit value Vlim.

[0083] Returning to the explanation of FIG. 14, subtractor 255 subtracts d-axis orthogonal-axis voltage Vdxl* output from voltage limiting unit 28 from d-axis orthogonal-axis voltage command value Vdx* output from voltage vector calculation unit 19. The result of this subtraction is input to one input of adder 259. The other input of adder 259 is the subtraction result of subtracting d-axis coaxial voltage Vdsl* from d-axis coaxial voltage command value Vds*. The two results are then added together in adder 259. The result of this addition is divided by divider 271 using speed information ω1*, and the sign is inverted by gain 275 to output as magnetic flux command value correction amount dφq2. Since the sign of dφq2 is reversed, the sign is inverted by gain 275. As a result, magnetic flux command value correction amount dφq2 corresponding to the voltage excess in the coaxial direction of the d-axis out of the voltage excess that exceeds the voltage limit value is obtained.

[0084] Furthermore, subtractor 257 subtracts the q-axis orthogonal-axis voltage Vqxl* output from voltage limiting unit 28 from the q-axis orthogonal-axis voltage command value Vqx* output from voltage vector calculation unit 19. This subtraction result is divided by divider 273 using speed information ω1*, and the result is output as magnetic flux command value correction amount dφq2. The magnetic flux command value correction amounts dφd2 and dφq2 represent the influence caused by limiting the orthogonal-axis component.

[0085] As shown in FIG. 7, correction amount calculation unit 27 connected to voltage limiter 28 of Example 2 shown in FIG. 9 needs to reduce the orthogonal-axis component when the orthogonal-axis component exceeds the voltage limit value. However, simply reducing the amplitude while maintaining the direction of the orthogonal-axis component makes magnetic flux control ineffective. When the orthogonal-axis component reaches the voltage limit value, a flux-weakening current needs to be applied to reduce the voltage vector, so proportional-integral control on the d-axis side needs to be maintained. Therefore, in calculating the magnetic flux command value correction amount dφq2, adder 259 shown in FIG. 14 takes into account the coaxial component on the d-axis side and provides a margin to the d-axis voltage that allows d-axis magnetic flux control to be maintained. That is, as shown in FIG. 14, subtractors 255 and 257 subtract the d-axis orthogonal-axis voltage command value Vdx* and the q-axis orthogonal-axis voltage command value Vqx* after voltage limiting, and then add the voltage limit amount of the coaxial voltage command value on the d-axis only. This makes it possible to prevent the flux weakening control from becoming ineffective even when the orthogonal axis component exceeds the voltage limit value, as shown in Fig. 7. The proportional-plus-integral control unit 60' of the second dq-axis flux command calculation unit 25 shown in Fig. 12 subtracts the flux command value correction amount dφq2 from the integrator 163. That is, the second dq-axis flux command calculation unit 25 corrects the integrator 163 applied to the q-axis based on the flux command value correction amount dφq2, which corresponds to the voltage excess amount in the coaxial direction with the d-axis, out of the voltage excess amount.

[0086] This allows the second dq-axis magnetic flux command calculation unit 25 to take into account the coaxial component on the d-axis side, providing a margin for maintaining d-axis magnetic flux control. As shown in Figure 7, the orthogonal axis component exceeds the voltage limit value when the speed of the motor 1 increases suddenly or the voltage of the DC voltage source 9 decreases suddenly, specifically when the speed increases suddenly due to idling, as in the case of an electric vehicle such as an electric car. In this way, even when the orthogonal axis component exceeds the voltage limit value, flux-weakening control is activated, preventing current control from becoming ineffective.

[0087] According to this embodiment, when the voltage command value based on the magnetic flux command value is limited, stable current control can be achieved even when the voltage is close to the voltage limit.

[0088] [Third embodiment] 15 is a configuration diagram of an electric vehicle 1000 according to the third embodiment of the present invention. This electric vehicle 1000 is a vehicle using, as a drive source, a motor 1 controlled by the synchronous machine control device 100 described in the first embodiment or the synchronous machine control device 100′ described in the second embodiment.

[0089] As shown in Fig. 15, synchronous machine control devices 100, 100' control the power supplied from a power converter 2 to a motor 1. A DC voltage source 9 such as a battery supplies power to the power converter 2. The motor 1 is connected to a transmission 101. The transmission 101 is connected to a drive shaft 105 via a differential gear 103, and supplies power to wheels 107. Note that a configuration may be adopted in which the transmission 101 is not used and the motor 1 is directly connected to the differential gear 103, or a configuration in which the motor 1 and power converter 2 are applied to both the front and rear wheels.

[0090] In electric vehicles 1000, such as electric vehicles and hybrid vehicles, efforts are being made to increase the speed of the motor 1 and improve the voltage utilization rate in order to reduce the size of the motor 1. To achieve this improvement in voltage utilization rate, the synchronous machine control devices 100, 100' control the inverter to use a high voltage up to the voltage limit value. However, according to this embodiment, stable current control can be achieved even near the voltage limit. In particular, the electric vehicle 1000 is required to operate stably near the voltage limit compared to other products, such as elevators. According to this embodiment, stable operation near the voltage limit is possible, leading to an improvement in the voltage utilization rate and ultimately a reduction in power consumption.

[0091] According to the embodiment described above, the following effects can be obtained. (1) A synchronous machine control device 100 that drives and controls a synchronous machine 1 includes a current command calculation unit 24 that calculates the difference between a current command value for the synchronous machine 1 and an actual current flowing through the synchronous machine 1 and generates a current command value by proportional-integral control, a voltage vector calculation unit 19 that generates a coaxial voltage command value and an orthogonal-axis voltage command value based on the current command value generated by the current command calculation unit 24, a voltage limiting unit 28 that limits the coaxial voltage command value with priority over the orthogonal-axis voltage command value so that the voltage command value does not exceed a predetermined voltage limit value, and a correction amount calculation unit 26 that calculates a current command value correction amount for correcting the current command value based on the limit by the voltage limiting unit 28, and the current command calculation unit 24 corrects the current command value by proportional-integral control based on the current command value correction amount. This makes it possible to achieve stable current control even when the current is near the voltage limit.

[0092] (2) In the synchronous machine control device 100′ that drives and controls the synchronous machine 1, the synchronous machine control device 100′ includes: a first magnetic flux command calculation unit 21 that generates a first magnetic flux command value from a current command value for the synchronous machine 1; a magnetic flux estimation unit 23 that determines a magnetic flux estimation value from an actual current flowing through the synchronous machine 1; a second magnetic flux command calculation unit 25 that calculates a difference between the first magnetic flux command value and the magnetic flux estimation value and generates a second magnetic flux command value by proportional integral control; a voltage vector calculation unit 19 that generates a voltage command value including a coaxial voltage command value and an orthogonal axis voltage command value based on the second magnetic flux command value; a voltage limiting unit 28 that limits the coaxial voltage command value with priority over the orthogonal axis voltage command value so that the voltage command value does not exceed a predetermined voltage limit value; and a correction amount calculation unit 27 that calculates a magnetic flux command value correction amount for correcting the second magnetic flux command value based on the voltage limit by the voltage limiting unit 28, and the second magnetic flux command calculation unit 25 corrects the second magnetic flux command value by proportional integral control based on the magnetic flux command value correction amount. This allows stable current control to be achieved even when the voltage is close to the limit.

[0093] (3) A synchronous machine control method for driving and controlling a synchronous machine 1 includes calculating a difference between a current command value for the synchronous machine 1 and an actual current flowing through the synchronous machine 1 to generate a current command value through proportional-integral control, generating a voltage command value consisting of a coaxial voltage command value and a orthogonal-axis voltage command value based on the generated current command value, limiting the coaxial voltage command value with priority over the orthogonal-axis voltage command value so that the voltage command value does not exceed a predetermined voltage limit value, calculating a current command value correction amount for correcting the current command value based on the limit, and correcting an integrator applied to the coaxial in the proportional-integral control based on the current command value correction amount equivalent to the coaxial component excess of the voltage excess that exceeds the voltage limit value due to the limit. This makes it possible to achieve stable current control even near the voltage limit.

[0094] The present invention is not limited to the above-described embodiments, and other embodiments that are conceivable within the scope of the technical concept of the present invention are also included within the scope of the present invention as long as they do not impair the characteristics of the present invention. Furthermore, configurations that combine the above-described embodiments may also be used. [Explanation of symbols]

[0095] 1 Motor, 2 Power converter, 3 Phase current detector, 4 Magnetic pole position detector, 5 Frequency calculation unit, 6 DC voltage detector, 7 Current coordinate conversion unit, 9 DC voltage source, 11 Coordinate conversion unit, 12 PWM controller, 18, 19 Voltage vector calculation unit, 21 First dq-axis magnetic flux command calculation unit, 23 dq-axis magnetic flux estimation unit, 24 Second dq-axis current command calculation unit, 25 Second dq-axis magnetic flux command calculation unit, 26, 27 Correction amount calculation unit, 28, 29 Voltage limiting unit, 75 Amplitude · Phase angle calculation unit, 76·· Amplitude and phase angle calculation unit, 77·· Limitation unit, 78, 91, 93·· Cosine wave generation unit, 79, 92, 94·· Sine wave generation unit, 80, 81, 88, 89·· Multiplier, 82·· Limit value calculation unit, 83, 87·· Subtractor, 85·· Square root of difference calculation unit, 99·· Voltage selection unit, 99A·· Magnetic flux command value correction amount calculation unit, 100, 100'·· Synchronous machine control device, 101·· Transmission, 103·· Differential gear, 105·· Drive shaft, 107·· Wheels.

Claims

1. In a synchronous machine control device that drives and controls a synchronous machine, a current command calculation unit that calculates a difference between a current command value for the synchronous machine and an actual current flowing through the synchronous machine and generates a current command value by proportional-integral control; a voltage vector calculation unit that generates a voltage command value including a coaxial voltage command value and an orthogonal axis voltage command value based on the current command value generated by the current command calculation unit; a voltage limiting unit that limits the coaxial voltage command value in priority to the orthogonal axis voltage command value so that the voltage command value does not exceed a predetermined voltage limit value; a correction amount calculation unit that calculates a current command value correction amount for correcting the current command value based on the voltage limit by the voltage limiting unit, The current command calculation unit corrects the current command value obtained by the proportional-integral control based on the current command value correction amount.

2. In a synchronous machine control device that drives and controls a synchronous machine, a first magnetic flux command calculation unit that generates a first magnetic flux command value from a current command value for the synchronous machine; a magnetic flux estimation unit that calculates a magnetic flux estimation value from an actual current flowing through the synchronous machine; a second magnetic flux command calculation unit that calculates a difference between the first magnetic flux command value and the magnetic flux estimation value and generates a second magnetic flux command value by proportional-integral control; a voltage vector calculation unit that generates a voltage command value including a coaxial voltage command value and an orthogonal axis voltage command value based on the second magnetic flux command value; a voltage limiting unit that limits the coaxial voltage command value in priority to the orthogonal axis voltage command value so that the voltage command value does not exceed a predetermined voltage limit value; a correction amount calculation unit that calculates a magnetic flux command value correction amount for correcting the second magnetic flux command value based on the voltage limit by the voltage limiting unit, The second magnetic flux command calculation unit corrects the second magnetic flux command value by the proportional-integral control based on the magnetic flux command value correction amount.

3. 2. The synchronous machine control device according to claim 1, The current command calculation unit corrects an integrator applied to the coaxial component of the proportional-integral control based on the current command value correction amount corresponding to the excess of a coaxial component of the voltage exceeding the voltage limit value due to the voltage limit.

4. 2. The synchronous machine control device according to claim 1, the current command calculation unit corrects an integrator applied to the orthogonal axis of the proportional-plus-integral control based on the current command value correction amount corresponding to an excess of an orthogonal axis component of a voltage excess that exceeds the voltage limit value due to the voltage limit.

5. The synchronous machine control device according to claim 3 or 4, The current command calculation unit corrects an integrator applied to the q-axis based on the current command value correction amount corresponding to the voltage excess in the coaxial direction of the d-axis, out of the voltage excess.

6. 3. The synchronous machine control device according to claim 2, The second magnetic flux command calculation unit corrects an integrator applied to the coaxial component of the proportional-integral control based on the magnetic flux command value correction amount corresponding to the excess of the coaxial component of the voltage exceeding the voltage limit value due to the voltage limit.

7. 3. The synchronous machine control device according to claim 2, the second magnetic flux command calculation unit corrects an integrator applied to the orthogonal axis of the proportional-plus-integral control based on the magnetic flux command value correction amount corresponding to an excess of an orthogonal axis component of a voltage exceeding the voltage limit value due to the voltage limit.

8. The synchronous machine control device according to claim 6 or 7, The second magnetic flux command calculation unit is a synchronous machine control device that corrects an integrator applied to the q-axis based on the magnetic flux command value correction amount corresponding to the voltage excess amount in the coaxial direction of the d-axis, out of the voltage excess amount.

9. The synchronous machine control device according to claim 1 or 2; an electric vehicle comprising a synchronous machine that is drive-controlled by the synchronous machine control device;

10. A synchronous machine control method for driving and controlling a synchronous machine, comprising: a difference between a current command value for the synchronous machine and an actual current flowing through the synchronous machine is calculated to generate a current command value by proportional-integral control; generating a voltage command value including a coaxial voltage command value and a quadrature-axis voltage command value based on the generated current command value; limiting the coaxial voltage command value in preference to the orthogonal axis voltage command value so that the voltage command value does not exceed a predetermined voltage limit value; calculating a current command value correction amount for correcting the current command value based on the limit; A synchronous machine control method for correcting an integrator applied to the coaxial motor in the proportional-integral control based on a current command value correction amount corresponding to the excess of the coaxial motor component among the voltage excess that exceeds the voltage limit value due to the restriction.

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