Current control device and drive system for differential double-wound synchronous motor

Abstract

This invention provides a current control device and a drive system for a dual-winding synchronous motor that solve the current control instability phenomenon caused by inter-system interference resulting from magnetic coupling between three-phase windings in a dual-winding synchronous motor using a method with relatively low computational load. [Solution] A current control device 32 that vector-controls the stator current flowing through a differential double-wound synchronous motor, wherein the differential double-wound synchronous motor consists of a rotor having permanent magnets and a stator having a first three-phase winding and a second three-phase winding, the first three-phase winding and the second three-phase winding having different inductances, and the current control device 32 controls the stator current by performing a conversion of current and voltage through a normalization coefficient consisting of the relative inductance ratio of the first three-phase winding and the second three-phase winding, treating the first three-phase winding and the second three-phase winding as a control model without magnetic interference.

Description

[Technical Field]

[0001] The present invention relates to a current control device and a drive system for a differential double-wound synchronous motor. More specifically, it relates to a current control device and a drive system for a differential double-wound synchronous motor in which two of the three-phase windings have different winding characteristics. [Background technology]

[0002] First, to ensure clarity of explanation and for other purposes, the following terms are defined. A motor drive system that includes a current control device and a power converter is referred to as a "drive system." A drive that generates the desired torque in an electric motor while minimizing the motor's electrical losses (copper loss, iron loss) is called an "efficient drive." The maximum rotor speed at which a permanent magnet synchronous motor can efficiently drive depends on the maximum voltage that the power converter can generate. This upper limit is called the "efficiency upper limit speed." The maximum voltage that the power converter can generate is called the "maximum voltage," and the limitation of the control system to this maximum voltage is called the "voltage limit." When a permanent magnet synchronous motor is driven at a speed exceeding its efficiency limit, it operates under voltage limitations. This type of drive is called "voltage-limited drive." A motor with a double winding arrangement of the three-phase windings, which were previously a single winding in a permanent magnet synchronous motor, is called a "double-wound synchronous motor." Among double-wound synchronous motors, a motor in which the winding characteristics (inductance and impedance) of the two three-phase windings are different is called a "differential double-wound synchronous motor." Figure 1 shows an example of the winding arrangement of a conventional permanent magnet synchronous motor, and Figure 2 shows an example of the winding arrangement of a differential double-wound synchronous motor. The two three-phase windings of a double-wound synchronous motor are referred to as the "first winding" (or "first three-phase winding") and the "second winding" (or "second three-phase winding"), respectively. The system associated with the first winding is referred to as the "first system," and the system associated with the second winding is referred to as the "second system." The first and second windings can be configured with or without a phase difference.

[0003] Furthermore, in order to simplify the technical explanations that follow, several points will be clarified. First, we define the coordinate system. Figure 3 is a diagram showing the coordinate system relationship of a double-wound synchronous motor (differential double-wound synchronous motor). The phases of the two three-phase windings of the double-wound synchronous motor are denoted as u-phase, v-phase, and w-phase. In the figure, the central axis of the u-phase coil of the first winding is the 1u-axis (u1), and the central axis of the u-phase coil of the second winding is the 2u-axis (u2), with the phase difference between the 1u-axis and the 2u-axis being Δθα. We define the αβ fixed coordinate system as a two-axis Cartesian coordinate system with the same axis as the 1u-axis as the base axis. In this case, the β-axis is defined as being rotated 90 degrees counterclockwise from the α-axis. In subsequent two-axis Cartesian coordinate systems, the secondary axis is also defined as being rotated 90 degrees counterclockwise from the base axis. Furthermore, we define the dq synchronous coordinate system as a two-axis Cartesian coordinate system with the direction of the rotor's north pole as the base axis. In this coordinate system, the rotor electric velocity ω n This is a rotating coordinate system.

[0004] As is well known in the field of motor control, the three-phase windings of a synchronous motor can be treated equivalently as the d-axis winding and the q-axis winding in the dq-synchronous coordinate system. The two three-phase windings of a double-winding synchronous motor can be treated as the d-axis first winding and the q-axis first winding, and the d-axis second winding and the q-axis second winding, respectively, in the dq-synchronous coordinate system. From this point forward, unless otherwise specified, the signal footnotes 1 and 2 will be used to indicate the relationship with the first and second systems, and the footnote dq will be used to indicate the relationship with the d-axis and q-axis.

[0005] The background technology is explained below. Permanent magnet synchronous motors are used as the main motors in electric vehicles, fuel cell electric vehicles, and hybrid electric vehicles. Conventional permanent magnet synchronous motors (hereinafter sometimes referred to as "conventional motors") had a problem in that their efficiency decreased significantly when driven at speeds exceeding their efficiency limit. The reason for this is explained below.

[0006] Generally, when the induced voltage generated by the rotation of an electric motor exceeds the maximum voltage, the drive system loses its desired current control performance. Since the induced voltage generated by a permanent magnet synchronous motor is mainly proportional to the rotational speed, current control becomes impossible when the rotational speed exceeds the efficiency limit speed in efficient drive. In conventional machines, to avoid this and drive at speeds above the efficiency limit speed, efficient drive is abandoned, and voltage-limited drive is used to achieve the desired speed and torque. The control method for this purpose is flux weakening control.

[0007] In flux weakening control, when the voltage value required by the controller approaches the maximum voltage, the current is controlled in a direction that weakens the magnetic flux from the rotor permanent magnets with the magnetic flux created by the stator current, thereby keeping the generated voltage below the maximum voltage. Flux weakening control is essential for applications requiring high-speed rotation, such as electric vehicles, but because flux weakening control requires a large amount of current that does not contribute to torque generation, it significantly reduces the efficiency of the motor. Consequently, conventional motors experienced a significant decrease in efficiency at speeds above their efficiency limit.

[0008] To address the aforementioned problems, a dual-winding synchronous motor with different winding characteristics (different winding-induced characteristics) has been proposed (see Non-Patent Document 1). In a dual-winding synchronous motor with different winding characteristics, the induced voltage due to the rotor magnetic flux differs for each of the two three-phase windings, and the efficiency limit speed also differs for each of the two three-phase windings. Hereafter, the three-phase winding with the lower efficiency limit speed will be referred to as the first winding, and the three-phase winding with the higher efficiency limit speed will be referred to as the second winding. Furthermore, the efficiency limit speed of the first winding will be referred to as the first efficiency limit speed, and the efficiency limit speed of the second winding will be referred to as the second efficiency limit speed.

[0009] In a dual-winding synchronous motor, when driving at a speed lower than the first efficiency limit speed, both three-phase windings are energized simultaneously. When driving at a speed above the first efficiency limit speed, the first winding is electrically disconnected, thereby stopping the energization of the first winding, which would otherwise experience a decrease in efficiency, and driving the motor solely with the second winding. This avoids flux weakening control and allows for increased speed while maintaining efficient driving up to the second efficiency limit speed.

[0010] When comparing a differential double-wound synchronous motor with a conventional motor that has the same structure as the conventional motor except for the windings and has similar output characteristics, the second efficiency limit speed of the differential double-wound synchronous motor is higher than that of the conventional motor. Therefore, the differential double-wound synchronous motor can avoid the efficiency reduction that was present in the conventional motor. In other words, the differential double-wound synchronous motor can be expected to have higher efficiency than the conventional motor.

[0011] Thus, while dual-winding synchronous motors can achieve higher efficiency than conventional motors, they have the problem of instability in current control due to the magnetic coupling of the two three-phase windings. When a voltage caused by a current change in one three-phase winding is generated in the other three-phase winding, it becomes a voltage disturbance to the current control system. This voltage disturbance occurring mutually between the two windings causes oscillations and divergences in the current response. Such phenomena can lead not only to a decrease in motor efficiency but also to a loss of control of the motor due to burnout of the motor or power converter.

[0012] This phenomenon will be explained in detail. A differential double-wound synchronous motor is a mutual induction circuit with two power sources. Here, we will use a model on the dq synchronous coordinate system and explain it with respect to the d-axis signal, but the discussion is exactly the same for the q-axis signal.

[0013] From equation (8) shown below, which represents the mathematical model of a differential double-wound synchronous motor in the dq synchronous coordinate system, the mathematical models for the d-axis voltage of the differential double-wound synchronous motor are given by equations (1) and (2).

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[0014] Arranging formula (1) with respect to current gives the following formula.

Mathematical Expression

[0015] Here, as a motor drive system that enables appropriate control of each winding current even when there is strong mutual induction between two windings, there is the current control device described in Patent Document 1.

[0016] Hereinafter, the current control method described in Patent Document 1 is referred to as the conventional technique. FIG. 4 cites the current control device of the conventional technique. 331d and 331q in the figure are the main parts of the current control device (G dfs (S), G qfs (S) in the figure correspond to the current controllers). The definition of matrix T d is given in formula (4a), and the definition of matrix K dv is given in formula (6b). The same applies to T q and K qv , except for the difference in subscripts.

Mathematical Expression

Mathematical Expression

Mathematical Expression

Mathematical Expression

[0017] [Patent Document 1] Japanese Patent Publication No. 2019-37111 [Non-patent literature]

[0018] [Non-Patent Document 1] Shinji Shinnaka, Ryu Hosooka, Kazuki Umeno, Naoto Nakamura: "Efficient Driving Method for Independent Double Three-Phase Wound Permanent Magnet Synchronous Motors with Different Winding-Induced Characteristics," Transactions of the Institute of Electrical Engineers of Japan, Vol. 137, No. 7, pp. 599-611 (2017)

[0019] [Non-Patent Document 2] Shinji Shinnaka: "Three-phase permanent magnet synchronous motor with inverse double three-phase windings with 180-degree spatial phase difference," Transactions of the Institute of Electrical Engineers of Japan, Vol. 137, No. 2, pp. 75-86 (2017) [Overview of the project] [Problems that the invention aims to solve]

[0020] The core of the prior art described in Patent Document 1 is to treat the controlled object as a first-order lag system through a transformation of the control model, as shown in equations (6a) and (6b).

[0021] This conversion involves the motor parameters, specifically resistance values ​​(R1, R2) and self-inductance value (L 1d , L 2d ), mutual inductance value (M d The matrix T is determined through equations (4a), (4b), and (5) using ). d It will be carried out by [the specified method]. In other words, the prior art described in Patent Document 1 was highly dependent on motor parameters.

[0022] However, motor parameters are not constant and can fluctuate during operation. For example, resistance values ​​fluctuate due to heat generation during operation, and inductance values ​​also fluctuate due to magnetic saturation. Therefore, in conventional technology, when resistance fluctuations or magnetic saturation occur, matrix T d The calculation of the matrix T required recalculation, but the operations in equations (4a), (4b), and (5) heavily utilize square root operations and division, d The recalculation was increasing the computational load.

[0023] The present invention has been made with the above matters in mind, and aims to provide a current control device and a drive system for a dual-winding synchronous motor that solve the phenomenon of current control instability caused by inter-system interference (magnetic interference) resulting from magnetic coupling between three-phase windings in a dual-winding synchronous motor in a manner with relatively low computational load. [Means for solving the problem]

[0024] To solve the above problems, we decided to implement control by treating the dual-winding synchronous motor as a control model in which there is no magnetic interference between the first and second three-phase windings. Specific examples are given below.

[0025] (Aspect 1) A current control device for vector-controlled stator current flowing through a differential double-wound synchronous motor, wherein the differential double-wound synchronous motor comprises a rotor having permanent magnets and a stator having a first three-phase winding and a second three-phase winding, the first three-phase winding and the second three-phase winding having different inductances, and the current control device controls the stator current by performing a conversion of current and voltage through a normalization coefficient consisting of the relative inductance ratio of the first three-phase winding and the second three-phase winding, treating the first three-phase winding and the second three-phase winding as a control model without magnetic interference. However, the normalization coefficient is N as shown in equations (21a) and (21b). d , N q That is the case.

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[0026] The current control device vector-controls the stator current flowing through a differential double-wound synchronous motor via power converters (e.g., two power converters) capable of supplying power to each of the two three-phase windings. Vector control is a current control method and is one of the control methods for permanent magnet synchronous motors. In vector control, the current component i that generates torque is controlled. d and the current component i that generates magnetic flux in the rotor q We consider them separately and control each current component independently.

[0027] This current control device can resolve the phenomenon of current control instability caused by inter-system interference resulting from magnetic coupling between three-phase windings in a dual-winding synchronous motor, using a method with relatively low computational load.

[0028] (Aspect 2) A current control device for vector-controlled stator current flowing through a differential double-winding synchronous motor, wherein the differential double-winding synchronous motor comprises a rotor having permanent magnets and a stator having a first three-phase winding and a second three-phase winding, the first three-phase winding and the second three-phase winding having different inductances, and includes a control deviation conversion unit that performs calculations on the control deviation between the current command value and the response current, and a PI control unit that performs PI control calculations based on the calculation results obtained by the control deviation conversion unit, wherein the control deviation conversion unit performs the calculation of the following equation (35) to control the stator current by treating the first three-phase winding and the second three-phase winding as a control model without magnetic interference.

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[0029] Here, the adjustment coefficient is a coefficient that the designer can arbitrarily set. For example, the value of the adjustment coefficient is K d =K q If we set =1, this formula means that the control model has been unified to the primary side parameters (R1, L1, M), and K d =N d , K q =N q This means that the control model has been standardized using secondary parameters (R2, L2, M). The choice of which parameters to use can be changed depending on ease of implementation, etc.

[0030] In vector control, the three-phase AC current (stator current) is converted to two-phase currents iα and iβ by the Clarke transform (αβ transform), and then the rotational coordinate transform (dq transform, Parke transform) is applied to i d and i q In this invention, when converting to the stator current i, d i q and current command value i* d , i * q the control deviation with respect to is converted by a control deviation converting unit according to formula (35), and this is corrected by PI control or the like so as to eliminate the deviation from the ideal value (current command value).

[0031] This current control device can solve the current control destabilization phenomenon caused by inter-system interference (magnetic interference) resulting from magnetic coupling between three-phase windings in a different-double-winding synchronous motor by a method with a relatively small computational load.

[0032] (Aspect 3) The current control device according to aspect 2, further comprising an operation amount conversion unit that performs calculation on a voltage command value output from a PI control unit, wherein the operation amount conversion unit performs calculation according to the following formula (37). [Math.]] wherein v * pd , v * nd , v * pq , v * nq are voltage command values (divided power), v ~* 1d , v ~* 1q are model voltages of a first three-phase winding, v ~* 2d , v ~* 2q are model voltages of a second three-phase winding, N d , N q are normalization coefficients, K d , K q are adjustment coefficients.

[0033] This current control device can solve the current control destabilization phenomenon caused by inter-system interference resulting from magnetic coupling between three-phase windings in a different-double-winding synchronous motor by a method with a relatively small computational load.

[0034] (Aspect 4) A current control device according to any one of aspects 1 to 3, wherein the approximate value shown in equation (22) below is used as the normalization coefficient.

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[0035] This current control device can resolve the phenomenon of current control instability caused by inter-system interference resulting from magnetic coupling between three-phase windings in a dual-winding synchronous motor, using a method with relatively low computational load.

[0036] (Aspect 5) A drive system for a differential double-wound synchronous motor having a current control device described in any one of aspects 1 to 4.

[0037] This dual-winding synchronous motor drive system is a system in which the phenomenon of current control instability caused by inter-system interference resulting from magnetic coupling between the three-phase windings in a dual-winding synchronous motor is resolved in a relatively computationally intensive way. [Effects of the Invention]

[0038] The present invention provides a current control device and a drive system for a dual-winding synchronous motor that can resolve the phenomenon of current control instability caused by inter-system interference (magnetic interference) resulting from magnetic coupling between three-phase windings in a dual-winding synchronous motor using a method with relatively low computational load. [Brief explanation of the drawing]

[0039] [Figure 1] Conventional synchronous motor winding configuration example [Figure 2] Example of winding configuration for a dual-winding synchronous motor. [Figure 3] Coordinate system of a dual-wound synchronous motor [Figure 4] Configuration of a conventional current control device [Figure 5]Configuration example of a drive system for a different double-winding synchronous motor using the current control device of the present invention [Figure 6] Configuration example of the current control device of the present invention based on an embodiment DETAILED DESCRIPTION OF THE INVENTION

[0040] Hereinafter, a current control device and a drive system for a different double-winding synchronous motor will be described by way of example. The present invention and each component are not limited to the following embodiments and the like.

[0041] First, based on the analysis below, the effect of the current control device of the present invention will be described. The mathematical model of the different double-winding synchronous motor in the dq synchronous coordinate system is given by the following formula (see Non-Patent Document 2). [MATH.]] [MATH.]] [MATH.]] [MATH.]]

[0042] In order to solve the problem of the present invention, the current control device of the present invention uses a virtual resistance R that satisfies the following relationship ~ 1d , R ~ 1q , R ~ 2d , R ~ 2q . [MATH.]] [MATH.]] The value of the virtual resistance is arbitrary as long as it satisfies the above formula, and there is freedom in design.

[0043] Using virtual resistance, the mathematical model of a differential double-wound synchronous motor can be expressed as follows:

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[0044] Using the relative inductance ratio of the differential double-wound synchronous motor, the following normalization coefficient N d , N q Define.

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[0045] Furthermore, if the first and second windings of a dual-winding synchronous motor have the same series-parallel structure, the number of turns of the first winding is n1 and the number of turns of the second winding is n2, and the normalization coefficient N d , N qThis can be approximated by the turns ratio.

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[0046] Also, the normalization coefficient N d , N q Using this, virtual resistance and self-inductance can be expressed as follows:

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[0047] Normalization coefficient N d , N q Using this method, the stator current is divided into the following divided currents i p i n Consider converting it to [this format].

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[0048] In this case, the reverse conversion from the division current to the stator current is given by the following equation.

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[0049] Equation (14), which is a mathematical model of a differential double-wound synchronous motor using virtual resistance, can be rewritten according to the definitions of equations (25) and (27) to obtain the following equation.

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[0050] In equations (32) and (33), the value of the adjustment coefficient is K. d =K q If we set =1, this formula means that the control model has been unified to the primary side parameters (R1, L1, M). On the other hand, K d =N d , K q =N q Therefore, the control model can be standardized using secondary parameters (R2, L2, M).

[0051] As is clear from the above, treating the control model as a partitioned model offers the following advantages. 1. Elimination of intersystem interference terms (control model without magnetic interference) 2. The controlled system is a first-order lag system. 3. Insensitive to magnetic saturation and resistance fluctuations. As can be seen from equations (29), (30), (32), and (33), the controlled system of the partitioned model is a first-order lag system, and there is no interference term. Furthermore, the division model is obtained by converting the stator current to a divided current and the stator voltage to a divided voltage through a transformation matrix consisting of normalization coefficients N. Since the normalization coefficients do not depend on resistance fluctuations or magnetic saturation, the current control device of the present invention, which controls the division model, does not require any special measures for resistance fluctuations or magnetic saturation. Therefore, the current control device of the present invention, based on a segmented model, is free from increased computational load due to resistance fluctuations and magnetic saturation. The current control device of the present invention, having these features, can solve the problems of the present invention. [Examples]

[0052] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0053] An embodiment of current control based on a segmented model in the implementation of the present invention is shown. The overall configuration diagram of the control system is shown in Figure 5. The segmented current controller (current control device) of the present invention, like a general controller, takes the dq axis current command value and the dq axis current, which is the control response, as inputs.

[0054] The following describes the control flow of the dq axis current. The current command value and the divided current command value on the dq synchronous coordinate system have the following relationship, similar to equation (25).

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[0055] From the above equation and equation (25), the following relationship holds regarding the control deviation between the current command value and the response current.

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[0056] The control deviations in the above equations are each applied to controller C pd (s), C nd (s), C pq (s), C nq (s) is used as input to generate a divided voltage command value. As for the controller design method, known controller design methods for first-order lag systems, such as the PI controller design method, can be applied based on the transfer functions of equations (32) and (33).

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[0057] Division voltage command value v * pd , v * nd , v * pq , v * nq This is converted to a model voltage command value based on equation (28).

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[0058] Model voltage command value v * 1d , v * 2d , v * 1q , v * 2q This is converted to a dq voltage command value based on equations (15) and (16).

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[0059] The process in equation (38) involves the virtual resistor R. ~ 1d , R ~ 2d , R ~ 1q , R ~ 2q It is necessary to set this. For example, the following can be selected to satisfy the relationships in equations (12), (13), and (23).

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[0060] In this case, the virtual resistance error defined by equations (19) and (20) is given by the following equation.

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[0061] An example based on the above is shown in Figure 6. In the same figure, the value of the adjustment coefficient is K d =K q =1. As mentioned above, Figures 321a and 321b correspond to equation (35), Figures 322a and 322b correspond to equation (36), Figures 323a and 323b correspond to equation (37) ((28)), and Figures 324a and 324b correspond to equation (38).

[0062] Figure 5 illustrates the overall configuration of a drive system for a differential double-wound synchronous motor including the current control device of the present invention. As shown in this figure, the drive system for the differential double-wound synchronous motor 1 comprises the differential double-wound synchronous motor 1, a power converter unit 2, and a computing device 3.

[0063] The power converter unit 2 has two power converters 21 that supply power to each of the two three-phase windings. Inverters, matrix converters, and other types of power converters 21 are commercially available and can be used. The power converter unit 2 includes a current sensor 22. In the example in Figure 5, a current sensor 22 is attached to each of the two power converters 21. Note that in the example in Figure 5, the current sensor 22 is only shown on the power converter 21 shown in the upper part of the figure, while the current sensor 22 is omitted for the power converter (21) shown in the lower part of the figure. Generally, two current sensors are required to obtain the current of one three-phase winding.

[0064] The arithmetic unit 3 includes a signal conversion unit 31 and a divided current controller 32 (current control device). The signal conversion unit 31 converts the stator current and stator voltage command values ​​of the first and second windings. Specifically, the signal conversion unit 31 is configured with a two-phase to three-phase converter (three-phase to two-phase converter) and a vector rotator for each winding so that the current control of the first and second windings can be performed independently. The signal conversion unit 31 is basically the same as those used conventionally. Of the calculation unit 3, the divided current controller 32 (current control device) includes control deviation conversion units 321a, 321b, PI control units 322a, 322b, manipulated variable conversion units 323a, 323b, and modeling processing units 324a, 324b. The current control device of the present invention corresponds to the divided current controller 32 in Figure 5. In the same figure, the three-phase current and voltage are represented by the foot notation t, and the current and voltage on the dq synchronous coordinate system are represented by the foot notation r. In this case, the relationship between each current and voltage is given by the following equation.

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[0065] The current control device of the present invention requires acquiring current information flowing through two three-phase windings and converting it into current information on a dq synchronous coordinate system. The current information is acquired from the current sensor 22. The acquired three-phase current information is passed to the signal conversion unit 31 and converted into current information on a dq synchronous coordinate system. The two matrices S and R(θ) of the signal conversion unit 31 are defined as follows.

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[0066] Current information on the dq synchronous coordinate system is passed to the divided current controller 32. Figure 6 shows the configuration of the divided current controller in the embodiment. The current information on the dq synchronous coordinate system passed to the divided current controller 32 is converted to control deviations of the divided currents by the control deviation conversion units 321a and 321b, and then the PI control units 322a and 322b perform the control. The manipulated variables of the PI control units 322a and 322b are converted to voltage command values ​​on the dq synchronous coordinate system by the manipulated variable conversion units 323a and 323b and the modeling processing units 324a and 324b. The voltage command value on the dq synchronous coordinate system is converted into a voltage command on the αβ fixed coordinate system by the signal conversion unit 31, then converted from two-phase to three-phase, and power is supplied to the three-phase windings of the differential double-wound synchronous motor by a power converter 21 such as an inverter.

[0067] This invention proposes a current control device based on a segmented model. A PI controller (PI control unit) can be used to control the segmented currents in the segmented model. Furthermore, current control in the segmented model does not require special handling for fluctuations in winding parameters. Therefore, the current control device of this invention can achieve stable and high-speed control using a PI controller.

[0068] Although the present invention has been described above with reference to specific embodiments and examples, the present invention is not limited to the above embodiments, and various changes and modifications can be made by experts in the relevant art without departing from the claims attached to this application. [Explanation of symbols]

[0069] 1. Differential double-wound synchronous motor 11. Two three-phase terminals of a double-wound synchronous motor 12. Rotor phase detector for a dual-wound synchronous motor 2 Power Conversion Unit 21 Power Converters 22 Current Sensor 3 Computing device 31 Signal conversion section 32-Division Current Controller (Current Control Device) 321a, 321b Control deviation conversion unit 322a,322b PI control section 323a, 323b Manipulated variable conversion unit 324a, 324b Modeling Processing Unit

Claims

1. A current control device that vector-controls the stator current flowing through a dual-wound synchronous motor, The aforementioned dual-winding synchronous motor comprises a rotor having permanent magnets and a stator having a first three-phase winding and a second three-phase winding, wherein the first three-phase winding and the second three-phase winding have different inductances. A current control device that controls the stator current by performing a conversion of current and voltage through a normalization coefficient consisting of the relative inductance ratio of the first three-phase winding and the second three-phase winding, thereby treating the first three-phase winding and the second three-phase winding as a control model without magnetic interference. However, the normalization coefficient is N as shown in equations (21a) and (21b). ｄ , N ｑ That is the case. [Math 21]

2. A current control device that vector-controls the stator current flowing through a dual-wound synchronous motor, The aforementioned dual-winding synchronous motor comprises a rotor having permanent magnets and a stator having a first three-phase winding and a second three-phase winding, wherein the first three-phase winding and the second three-phase winding have different inductances. A control deviation conversion unit that performs calculations on the control deviation between the current command value and the response current, This includes a PI control unit that performs PI control calculations based on the calculation results obtained by the control deviation conversion unit, A current control device that controls the stator current by performing the calculation of the following equation (35) in the control deviation conversion unit, thereby treating the first three-phase winding and the second three-phase winding as a control model in which no magnetic interference exists. [Number 35] however, i ＊ 1ｄ , i ＊ ２ｄ ,i ＊ １ｑ , i ＊ ２ｑ is a current command value, i １ｄ i １ｑ , is the response current of the first three-phase winding, i ２ｄ i ２ｑ This is the response current of the second three-phase winding. N ｄ , N ｑ These are the normalization coefficients shown in equations (21a) and (21b), K ｄ _K ｑ is the adjustment coefficient. i ＊ ｐｄ -i ｐｄ i ＊ ｎｄ -i ｎｄ i ＊ ｐｑ -i ｐｑ i ＊ ｎｑ -i ｎｑ This is the control deviation after calculation. [Math 21]

3. It further includes an manipulated variable conversion unit that performs calculations on the voltage command value output from the PI control unit, In the manipulated variable conversion unit, the calculation of the following equation (37) is performed: The current control device according to claim 2. [Number 37] however, v ＊ ｐｄ , v ＊ ｎｄ , v ＊ ｐｑ , v ＊ ｎｑ This is the voltage command value. v ～＊ １ｄ , v ～＊ １ｑ This is the model voltage of the first three-phase winding. v ～＊ ２ｄ , v ～＊ ２ｑ This is the model voltage of the second three-phase winding. N ｄ , N ｑ is the normalization coefficient, K ｄ _K ｑ This is the adjustment factor.

4. As the normalization coefficient, the approximate value shown in equation (22) below was used. A current control device according to any one of claims 1 to 3. [Number 22] However, n １ n is the number of turns of the first winding. ２ This is the turn number of the second winding.

5. A current control device according to any one of claims 1 to 4, A drive system for a dual-wound synchronous motor.

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