JP6806983B2 - Double three-phase winding permanent magnet synchronous motor drive system - Google Patents

Description

The present invention is a double three-phase winding permanent magnet synchronous type consisting of a rotor having a permanent magnet and a stator having two three-phase windings (first three-phase winding and second three-phase winding). The present invention relates to a drive system for a dual three-phase winding permanent magnet synchronous electric motor including at least an electric motor and a power converter capable of simultaneously supplying different three-phase currents to two three-phase windings. In the following description, for the sake of simplicity, the winding is used synonymously with the three-phase winding. The above-mentioned double three-phase winding permanent magnet synchronous motor is abbreviated as a double synchronous motor for the sake of simplicity. Furthermore, for the same reason, the drive system is abbreviated as a dual synchronous motor drive system. The applications of the dual synchronous electric motor drive system of the present invention are main drive of battery electric vehicles, fuel cell electric vehicles, hybrid electric vehicles, etc., and home appliances that are required to be efficiently driven over a wide range.

In the present invention, the portion of the dual synchronous motor in which the three-phase winding is applied is referred to as a "stator". The "stator" in the present invention is synonymous with "armature". There are Y type and Δ type in the three-phase winding applied to the stator. As is well known to those skilled in the art, when evaluated from a three-phase terminal, the characteristics of the Y-shaped winding and the characteristics of the Δ-shaped winding are equivalently converted to each other. In order to ensure the simplicity of the description, the technical description in this specification assumes a Y-shaped connection. This does not lose the generality of the invention, as evidenced by the existence of equivalent transformations.

In the present invention, a two-dimensional plane is grasped in polar coordinates, and the three terms of angle, spatial position, and spatial phase are used synonymously. These units are "radians" or "degrees". The angle, the spatial position, and the positive direction of the spatial phase in the present invention may be defined as either left-handed (counterclockwise) or right-handed (clockwise). However, in the present specification, in order to maintain the simplicity of the description, the positive direction of the angle, the spatial position, and the spatial phase is defined as left-handed (counterclockwise), and the present invention will be described. This does not lose the generality of the present invention.

In the present invention, a device that supplies AC power to a dual synchronous motor is referred to as a power conversion device. Inverters, matrix converters, and the like have been put into practical use as power converters, which are the main devices of power converters. The power converter for single / six-phase, two / three-phase, six / single-phase, etc. constitutes the power converter of the present invention.

In the present invention, the term "torque equivalent value" is used as a general term for a torque command value and a signal having a positive correlation characteristic with the torque command value.

Prior inventions relating to the dual synchronous motor targeted by the dual synchronous motor drive system of the present invention include, for example, Patent Document 1 and Non-Patent Documents 1 to 4. The previously reported double synchronous motors include a three-phase simple synchronous motor (Non-Patent Document 1) and a six-phase synchronous motor (Patent Document 1, Non-Patent Documents 2 to 3) from the viewpoint of arranging the double three-phase winding of the stator. ), And a three-phase reverse synchronous motor (Non-Patent Document 4).

With reference to Non-Patent Document 1, the outline of the conventional double synchronous motor (three-phase simple synchronous motor) is shown in FIG. 1 by taking the case where the pole logarithm Np is Np = 1. 1 is a double synchronous motor (including a rotor and a stator), 11 is a rotor of a double synchronous motor, 121 is a first winding of a stator of a double synchronous motor, and 122 is a double synchronous motor. The second winding of the stator of is shown respectively. In the figure, the first winding is shown by a solid line and the second winding is shown by a broken line in order to clarify the distinction between the first winding and the second winding of the stator. Further, since the second winding overlaps with the first winding due to the winding arrangement, the second winding is intentionally shifted to the right for drawing in order to avoid duplication in drawing.

The double synchronous motor (three-phase simple synchronous motor) with this arrangement has the following features. (A) For both the first winding and the second winding, the u-phase winding, the v-phase winding, and the w-phase winding are spatially 2π / 3 [rad] sequentially in a space based on the one-pole logarithm. It is arranged at the phase advance position. (B) In principle, the first winding and the second winding are arranged in space without any phase difference. (C) In principle, the pole logarithm can be any integer. That is, an odd or even number of pole pairs can be adopted. (D) When the first winding and the second winding are energized at the same time, or when only one of the windings is energized, the number of phases remains unchanged at three phases. (E) In principle, in the case of simultaneous energization of the first winding and the second winding, the currents of the first winding and the second winding need to be synchronized without a phase difference.

As a second example (example of a six-phase synchronous motor) of the stator winding arrangement of the double synchronous motor, the case where the pole logarithm Np is Np = 1 is taken as an example, and is shown schematically together with the rotor in FIG. (Drawing of winding resistance is omitted). The meanings of the drawn wire numbers 1, 11, 121, and 122 are the same as those in FIG. However, it is different from the example of FIG. 1 in that the arrangement of the second winding is spatially shifted by θ12 = π / 6 [rad] with respect to the first winding.

The double synchronous motor (six-phase synchronous motor) according to this arrangement has the following features as compared with the three-phase simple synchronous motor (FIG. 1). (A) Same as item (a) of Example 1. (B) In principle, the first winding and the second winding are arranged so as to have a spatial phase difference of π / 6 [rad] in a space based on a one-pole logarithm. (C) Same as item (c) of Example 1. (D) When the first winding and the second winding are energized at the same time, it operates as a six-phase motor, and when only one of the windings is energized, it operates as a three-phase motor. (E) In principle, in the case of simultaneous energization of the first winding and the second winding, the currents of the first winding and the second winding have a phase difference corresponding to the spatial phase difference. Synchronization is required.

As a third example of the stator winding arrangement of the double synchronous motor (example of the three-phase reverse synchronous motor), an example in the case where the pole logarithm Np is Np = 2 is shown schematically together with the rotor in FIG. (Drawing of winding resistance is omitted). The meanings of the drawn wire numbers 1, 11, 121, and 122 are the same as those in FIG.

The double synchronous motor (three-phase reverse synchronous motor) with this winding arrangement has the following features as compared with Examples 1 and 2. (A) For both the first winding and the second winding, the u-phase winding, the v-phase winding, and the w-phase winding are sequentially 2π / 3 [rad] spatial in the space based on the 2-pole logarithm. It is located at a phase lag position. (B) In principle, the first winding and the second winding are arranged so as to have a phase difference of ± π [rad] in a space based on a two-pole logarithm. (C) Only an even number of pole logarithms can be taken. That is, an odd number of pole pairs cannot be adopted. (D) Same as item (d) of Example 1. (E) Same as item (e) of Example 1.

Next, the conventional technology regarding the double synchronous motor drive system, that is, the drive system for the double synchronous motor will be introduced. FIG. 11 cites the drive system proposed in Patent Document 1, and shows a drive system particularly for the six-phase synchronous motor of FIG. 2 as a dual synchronous motor. As is clear from the figure, the d-axis current controller and the q-axis current controller are each single, and as a result, the d-axis voltage command value (Vd1) and the q-axis voltage command value, which are the outputs of the current controller, are used. (Vq1) is also single. The first system (system consisting of the first winding and the first power converter) and the second system (the system consisting of the first winding and the first power converter) have a single and thus the same d-axis voltage command. The value (Vd1) and the q-axis voltage command value (Vq1) are used. As a result, basically the same current flows through the first winding and the second winding. This system configuration is extremely rational when the first winding and the second winding have the same characteristics, in other words, when the motor parameters in the first system and the second system are the same. It is a composition.

In Non-Patent Document 1, the first is a three-phase simple synchronous motor, which is a kind of double synchronous motor, under the premise that the motor parameters are the same and that there is no salient pole characteristic. A dual synchronous motor drive system having the same current control system for the system and the second system has been proposed. Under the same parameters, it is a rational measure to pass basically the same current through the first winding and the second winding, at least from the viewpoint of minimizing loss, and two identical current control systems are provided. This system configuration has high rationality as in the example of Patent Document 1 (see FIG. 11).

In Non-Patent Document 4, an electric motor is presented on the premise that the electric motor parameters in each system are the same for a three-phase reverse synchronous motor, which is a kind of double synchronous motor. "Under the assumption that the motor parameters in each system are the same, the control measure of passing basically the same current through the first winding and the second winding" is rational from the viewpoint of minimizing loss. Similar to the case of the six-phase synchronous motor and the three-phase simple motor motor described above, a single current control system is shared or two identical current control systems are configured.

However, if the first winding and the second winding have different winding-induced characteristics, in other words, if the first system and the second system have different motor parameters, the previous "Volume 1" The "control policy of passing basically the same current through the wire and the second winding" has no rationality. For this reason, in the conventional double synchronous motor drive system constructed on the premise that the first system and the second system have the same motor parameters, the first winding and the second winding have different winding-derived characteristics. It would be completely unsuitable for a dual synchronous motor with.

Keiichiro Ban, Kazuyoshi Obayashi: "Electric Drive Device for Automobiles", Japanese Patent Application Laid-Open No. 2000-41392 (1998-7-23)

Akira Satake, Hiroshi Kato, Akira Imai: "Modeling of Multi-Wound Permanent Magnet Motors and Non-Interference Control Methods", Proceedings of the IEEJ Industrial Application Division, I, pp. 199-202 (2005) Takafumi Imai, Fumiaki Osawa, Yasushi Yamada, Yukio Inakuma: "Possibility of Standardization of EV / HEV Electric Drive Systems (Current Ripple Suppression of Multi-Phase Motors)", Proceedings of the National Conference of the Institute of Electrical Engineers of Japan, 4, pp. 361-362 (2016) Tatsuya Mori and Akira Furukawa: "Pulse pattern to reduce torque ripple in double three-phase PMSM drive 1 shunt current detection double inverter", Proceedings of the IEEJ Industrial Application Division, III, pp. 159-164 (2016) Shinji Shinnaka: "Three-phase permanent magnet synchronous motor with inverse double three-phase winding with 180 degree spatial phase difference (double winding arrangement, dynamic mathematical model, vector simulator)", 2016 Electrical Society Industry Proceedings of the Applied Division Conference, III, pp. 285-290 (2016)

The present invention has been made under the above background. If the first and second windings of a dual synchronous motor have different winding-derived characteristics, the motor will have the potential to achieve efficient drive over a wide range. However, conventional dual synchronous motor drive systems cannot take advantage of this potential. The present invention maximizes this potential, specifically, a drive system that generates torque that matches the torque command value with the minimum loss in the first winding and the second winding having different winding-derived characteristics. Is intended to provide.

In order to achieve the above object, the invention of claim 1 comprises a rotor having a permanent magnet and a stator having two three-phase windings (first three-phase winding and second three-phase winding). Permanent magnet synchronous motor, a power converter that can simultaneously supply different three-phase currents to two three-phase windings, and a tracking target for the three-phase current flowing through each three-phase winding from the torque command equivalent value. Current command value for three-phase winding (d-axis current command value and q-axis current command value for the first three-phase winding, d-axis current command value and q-axis current command value for the second three-phase winding) 4 The command converter that generates the current command value) and the current of each three-phase winding are controlled to follow through the power conversion device so that the current of each three-phase winding follows each generated current command value. A permanent magnet synchronous motor drive system comprising a current control unit and a vector control device comprising the permanent magnet synchronous motor so that the two three-phase windings provide different winding origin characteristics. The command conversion unit responsible for generating the 4-current command value is configured so as to minimize or quasi-minimize the loss of the permanent magnet synchronous motor due to the current controlled following the 4-current command value. It is characterized by.

The invention of claim 2 is the permanent magnet synchronous motor drive system according to claim 1, wherein at least 4 current command values are treated as variables, and as a solution of a multivariable simultaneous nonlinear equation corresponding to a torque command equivalent value. (4) The command conversion unit is configured to generate a current command value.

The invention of claim 3 is the permanent magnet synchronous motor drive system according to claim 2, wherein the solution of the multivariate simultaneous nonlinear equations corresponding to the torque command equivalent value is repeatedly calculated in real time for each control cycle. It is characterized in that the command conversion unit is configured so as to generate the four current command values obtained in.

The invention of claim 4 is the permanent magnet synchronous motor drive system according to claim 1 or 2, wherein the four current command values corresponding to the torque command equivalent value and bring about loss minimization are obtained in advance, and further. Prepares in advance an approximation function or reference table of the four current command values with the torque command equivalent value as an argument, and uses the approximation function or reference table with the torque command equivalent value as an argument for each control cycle. Is characterized in that the command conversion unit is configured so as to regeneratively generate the above in real time.

The effect of the present invention will be described. First, the effect of the invention of claim 1 will be described. A highly complete mathematical model is indispensable for constructing a rational drive system for the dual synchronous motor targeted by the present invention. In general, mathematical models include circuit equations (first basic formula) that describe motor characteristics as electric circuits, torque generation formulas (second basic formula) that describe motor characteristics as torque generators, and electrical energy to mechanical energy. It is composed of an energy transfer formula (third basic formula) that describes the characteristics of the motor as an energy converter to be converted. In a mathematical model with a high degree of perfection, these three basic formulas are mathematically consistent with each other.

The present invention newly constructs a mathematical model on the following dq synchronous coordinate system as a highly complete mathematical model for a dual synchronous motor in which two three-phase windings have different winding-induced characteristics. did.
Circuit equation (first basic equation)
Torque generation type (second basic type)
Energy transfer type (third basic type)

The legs 1 and 2 in the mathematical model mean the relation with the first winding (first system) and the second winding (second system), respectively, and the symbol "s" is the differential operator "d /". It means "dt". The physical quantity used in the mathematical model will be described by taking the first winding (first system) as an example. The 2 × 1 vectors v1 and i1 defined on the dq synchronous coordinate system mean the voltage and current of the stator, respectively. φ1i is the stator reaction magnetic flux (armor reaction magnetic flux) caused by the stator current, and φ1 is the rotor magnetic flux strength (velocity electromotive force constant). τ1 and τ mean the generated torque, and indicate the first system torque and the total torque, respectively. Further, pef is the applied (instantaneous) active power to the dual synchronous motor. ωm and ωn are the mechanical speed and the electric speed of the rotor having the following relationship via the pole logarithm Np.
R1 is the resistance of the stator winding. L1d and L1q are d-axis and q-axis (self) inductances, and Md and Mq are d-axis and q-axis (mutual) inductances between the first winding and the second winding. The self- and mutual mirror phase inductances have the following relationship with the self- and mutual d-axis and q-axis inductances.

In a double synchronous motor in which two three-phase windings have different winding-derived characteristics, at least one of the motor parameters (winding resistance R1, inductance L1d, L1q, rotor magnetic flux strength Φ1) is two. It will be different in the winding (system) of. In a dual synchronous motor in which two three-phase windings have different winding-derived characteristics, it is common for all four motor parameters to be different.

As shown in the torque generation equation of the equation (2), the total torque τ is the d-axis current i1d and the q-axis current i1q of the first winding, and the d-axis current i2d and the q-axis current i2q of the second winding. It is generated by interaction. As the equation clearly shows, of four currents (four currents of d-axis current and q-axis current of the first winding, d-axis current and q-axis current of the second winding) that bring about the same total torque. There are an infinite number of combinations. On the other hand, the first term on the right side of the energy transfer type (3a) means a loss (copper loss) due to four currents. The energy transfer formula indicates that "this loss varies depending on the four currents". The four currents, which have high engineering significance, are the currents that produce the specified torque with the minimum loss.

The invention of claim 1 first constitutes a permanent magnet synchronous motor so that the two three-phase windings provide different winding-derived characteristics from each other. This has the effect that the first winding can be configured to be suitable for low speed and large torque, and the second winding can be configured to be suitable for high speed and low torque. In this configuration, high-speed rotation is possible without the need for a weakening magnetic flux (weakening field) that causes a decrease in efficiency. According to the invention of claim 1, secondly, in the command conversion unit, torque is minimized or quasi-minimized so as to minimize or quasi-minimize the loss of the permanent magnet synchronous motor due to the current controlled following the 4-current command value. It becomes possible to generate a 4-current command value from a command equivalent value. As a result, according to the invention of claim 1, it is possible to generate torque having a high engineering meaning, and in particular, it is possible to obtain an effect that efficient driving is possible in a wide speed range from low speed to high speed.

Next, the effect of the invention of claim 2 will be described. When the torque generated by the logarithm of one pole is τN, the following relationship can be obtained from the torque generation equation (2) constructed by the present invention.
While generating the specified torque (Np · cτ), the problem of minimizing copper loss due to the stator current used for this is that the generated torque τN for the 1-pole pair in equation (6) is the 1-pole pair. Optimal with a constraint condition that the stator current for minimizing the copper loss shown in the first term on the right side of the energy transfer equation (3a) constructed by the present invention is specified after being constrained by the specified torque cτ of. It can be reconsidered as a "chemical problem". One of the effective solutions for this is the use of the Lagrange undetermined multiplier method.

Based on this understanding based on the mathematical model according to the present invention, a Lagrangian L composed of five variables (i1d, i1q, i2d, i2q, λ) including the Lagrangian multiplier λ is constructed as follows.
The equation (6) is applied to the right side of the equation (7), and the Lagrangian L is expressed by only five variables (i1d, i1q, i2d, i2q, λ). Then, if the Lagrangian is partially differentiated with five variables (i1d, i1q, i2d, i2q, λ) and set to zero, the following five-variable, five-simultaneous nonlinear simultaneous equations are obtained.

In the current control of the dual synchronous motor, only the winding current (i1d, i1q, i2d, i2q) as the solution of the equation (8) is required, and the variable λ as the solution of the equation (8) is Not needed. Taking this point into consideration when solving Eq. (8), if the variable λ is eliminated in advance from Eqs. 1 to 4 of Eq. (8), Eq. (8) is, for example, the following four variables and four simultaneous non-linearities. It can be changed to an equation.
It is pointed out that the above equation (9) is one of the four-variable, four-simultaneous nonlinear equations for four currents, and that there are various other ways to formulate the four-variable, four-simultaneous nonlinear equations for four currents. deep.

When the current control system performs current control according to the current command value, the 4 current values (i1d, i1q, i2d, i2q) obtained as solutions of 5 or 4 simultaneous nonlinear equations are used as the 4 current command values. (4 current command values of d-axis current command value i1d * and q-axis current command value i1q * for the first winding, d-axis current command value i2d * and q-axis current command value i2q * for the second winding) When treated as, a highly rational current command value that minimizes loss while generating a specified torque can be obtained. The invention of claim 2 is based on the above analysis result, and according to the invention of claim 2, a solution of a multivariable simultaneous nonlinear equation corresponding to a torque command equivalent value, which treats at least 4 current command values as variables. As a result, it becomes possible to generate a 4-current command value. As a result, according to the invention of claim 2, it is possible to obtain an effect that a current command value having high engineering rationality can be obtained concretely and accurately.

Next, the effect of the invention of claim 3 will be described. It is generally not easy to obtain an analytical solution of 5 or 4 simultaneous nonlinear equations. One of the practical methods is to obtain a solution by iterative operation. According to the invention of claim 3, the solution of the multivariable simultaneous nonlinear equations corresponding to the torque command equivalent value can be obtained by iterative calculation for each control cycle to generate a 4-current command value. Setting the initial value is important for high-speed convergence of the iterative operation, but if the final value one control cycle before is used as the initial value of the iterative operation of the current control cycle, it is repeated once or twice. You can get the desired convergence value with. As is already clear from the above description, according to the invention of claim 3, the effect that the optimum current command value can be surely obtained by a small number of operations in a limited control cycle can be obtained. As a result, the effect of enhancing the effect of the invention of claim 2 can be obtained.

Subsequently, the effect of the invention of claim 4 will be described. According to the invention of claim 4, a 4-current command value corresponding to the torque command equivalent value and causing loss minimization is obtained in advance, and further, an approximation function of the 4-current command value with the torque command equivalent value as an argument or A reference table is prepared in advance, and four current command values can be regenerated in real time by an approximation function or a reference table that takes a torque command equivalent value as an argument for each control cycle. Therefore, if an approximate function or a reference table is used, the amount of calculation required for the control cycle is very small. As is clear from the above, according to the invention of claim 4, it is possible to obtain the effect that the optimum current command value can be reliably generated in real time with a small number of calculations in a limited control cycle. As a result, the effect of enhancing the effect of the invention of claim 1 or claim 2 can be obtained. It should be noted that the four current command values to be obtained in advance corresponding to the torque command equivalent value and bring about the loss minimization can also be obtained by pre-solving the multivariable simultaneous nonlinear equations by utilizing the inventions of claims 2 to 3. .. It can also be obtained experimentally through preliminary experiments.

"A diagram showing an example of winding arrangement of a double three-phase winding permanent magnet synchronous motor (three-phase simple synchronous motor)" "Figure showing example of winding arrangement of double three-phase winding permanent magnet synchronous motor (six-phase synchronous motor)" "A diagram showing an example of winding arrangement of a double three-phase winding permanent magnet synchronous motor (three-phase reverse synchronous motor)" "A diagram showing a configuration example of a dual synchronous motor drive system when the present invention is applied to a three-phase simple synchronous motor and a three-phase reverse synchronous motor" "Figure showing configuration example of command converter" "Figure showing configuration example of repetitive arithmetic unit" "Figure showing configuration example of repetitive arithmetic unit" "Figure showing configuration example of repetitive arithmetic unit" "Figure showing configuration example of approximate commander" "Figure showing configuration example of approximate commander" "A diagram showing a configuration example of a conventional six-phase synchronous motor drive system"

Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

As the double synchronous motor, a three-phase simple synchronous motor and a three-phase reverse synchronous motor are selected, and an example of an embodiment of a drive system using all the inventions of claims 1 to 4 is shown in FIG. The drive system is largely composed of a double synchronous motor (including a rotor and a stator) 1, a power converter 2 (broken block display), and a vector control device 3 (broken block display). The power converter is composed of a power converter 21 for the first and second systems and a current detector 22. The vector control device 3 is largely composed of a command converter 31 that realizes a command conversion unit and a current control unit 32 (broken line block display) for the first and second systems. In the current control unit 32, each system has a three-phase two-phase converter 321a, a two-phase three-phase converter 321b, and a vector rotator 322a so that the current control of the first and second systems can be performed independently. 322b and current controller 323 are individually owned. The phase detector (resolver, encoder, etc.) 324 and speed detector 325 for the rotor correspond to a single rotor, and are shared by both systems. In the figure, for the sake of simplicity, a plurality of scalar signals are regarded as one vector signal, and the plurality of scalar signal lines are represented by one thick signal line. The two-phase signal (that is, the 2 × 1 vector signal) existing on the left side of the three-phase two-phase converter and the two-phase three-phase converter is represented by one thick signal line. The footsteps r and s of the vector signal indicate that they are signals on the dq synchronous coordinate system and signals in the αβ fixed coordinate system. Vector controllers today generally process signals digitally at specific control cycles. Hereinafter, the command converter, which is the core of the present invention, will be described on the premise that the vector control device operates digitally. Since the devices other than this device are basically the same as the previous ones, the description of these devices is omitted.

The command converter 31 is configured based on the invention of claims 2 to 4. FIG. 5 shows an example of an embodiment of a command converter using the inventions of claims 2 to 3. The torque command value τ * sent to the command converter 31 is divided by the pole logarithm Np and converted to cτ, and then processed by the iterative calculator 311. The iterative calculator 311 processes the designated torque cτ for the logarithm of one pole, generates a 4-current command value through the iterative calculation, and outputs it. There are various configurations of the iterative calculator 311. A configuration example of the repeater 311 is shown below.

The five-variable, five-simultaneous nonlinear simultaneous equations in Eq. (8) can also be rewritten as follows with respect to the currents of the first and second windings.

By referring to Eq. (10), the following iterative solution can be constructed.

The leg mark k in the equation (11) means the number of repetitions, and n in the equation (11b) means a positive integer. FIG. 6 shows a block diagram of an embodiment of a repetitive arithmetic unit on which the equation (11) is mounted. The following are examples of gain selection in the equation (11b).

Initial values of 5 variables are required for iterative operations. If the final value before one control cycle is used as the initial value of the iterative operation of the current control cycle, the desired convergence value can be obtained by the iterative operation once or twice. For the variable λ, the following equation gives a useful initial value.

In the mathematical model proposed by the present invention, the fifth equation of the equation (8) can be amended as follows by using the second and third equations of the equation (8).
By using the first to fourth equations of the equation (8) and the above equation (14), the block diagram of FIG. 7 is obtained as an example of the embodiment of the repeater. In the calculation block of the 4-current command value (calculation of the q-axis current command value, calculation of the d-axis current command value) in the figure, the first to fourth equations of the equation (8) are used. The initial value is also required in this embodiment. The handling of the initial values of this embodiment is the same as that of the embodiment of FIG.

The 5 × 1 vector variable x and the 5 simultaneous nonlinear equations that constrain it are defined as follows.
The specific definition of the simultaneous nonlinear equations in Eq. (15b) is as in Eq. (8). This simultaneous nonlinear equation can be solved by the following iterative operation.
The leg mark k means the number of repetitions. Jc is a 5 × 5 Jacobian defined by the following equation.
FIG. 8 is a block diagram showing an embodiment of a repetitive arithmetic unit on which the equation (16) is mounted. The initial value is also required in this embodiment. The handling of the initial values of this embodiment is the same as that of the embodiment of FIG.

As described above, three examples have been shown as examples of an embodiment of the iterative arithmetic unit for obtaining the solution of equation (8), which is a system of nonlinear equations, by iterative calculation, and eventually obtaining the four current command values. It should be pointed out that the embodiments according to the inventions of claims 2 to 3 are not limited to these three examples, and various other examples may exist. It is also pointed out that the solution of the four simultaneous nonlinear equations of Eq. (9) also gives the same 4-current command value as the solution of Eq. (8), and there are various examples of embodiments of the iterative arithmetic unit for this purpose. deep. The inventions of claims 2 to 3 do not exclude these examples of embodiments.

FIG. 9 shows an example of an embodiment using the invention of claim 4. The torque command value τ * sent to the command converter 31 is divided by the pole logarithm Np and converted into the designated torque cτ for one pole logarithm, and then sent to the approximation commander 312. The approximation commander 312 is provided with four approximation functions. The four approximate functions are the d-axis current command value for the first winding, the q-axis current command value, the d-axis current command value for the second winding, and q, respectively, according to the specified torque cτ for the logarithm of one pole. Generates the shaft current command value. As the 4-approximation function that generates the 4-current command value, the 4-current command value obtained in advance by using the inventions of claims 2 to 3 may be determined by polynomial approximation. Further, the four current command values obtained in advance experimentally may be determined by polynomial approximation. The coefficients of the polynomial may be determined by the least squares method or the like. As a matter of course, instead of the designated torque cτ for one pole logarithm, the torque command value τ * itself may be used to create a four approximation function.

FIG. 10 shows an example of a second embodiment using the invention of claim 4. The torque command value τ * sent to the command converter 31 is divided by the pole logarithm Np and converted into the designated torque cτ for one pole logarithm, and then sent to the approximation commander 312. Four reference tables are prepared for the approximation commander 312. The argument of the four reference tables is the specified torque cτ for one pole logarithm. The four reference tables are the d-axis current command value for the first winding, the q-axis current command value, the d-axis current command value for the second winding, and q, respectively, according to the specified torque cτ for one pole pair. Generates the shaft current command value. The 4 reference table for generating the 4 current command value may be prepared in advance by utilizing the inventions of claims 2 to 3. Further, the four current command values obtained in advance experimentally may be determined by polynomial approximation. As a matter of course, the reference table may be created by using the torque command value τ * itself as an argument of the reference table instead of the designated torque cτ for one pole logarithm.

In the above embodiment, the case where the torque command value itself is used as the torque command equivalent value is illustrated. In the present invention, the torque command equivalent value does not have to be limited to the torque command value itself. More specifically, it should be pointed out that any signal having a positive correlation with the torque command value can be treated as a torque command equivalent value.

The drive system configuration of FIG. 4 targets a three-phase simple synchronous motor and a three-phase reverse synchronous motor as the dual synchronous motor. When a six-phase synchronous motor is targeted as a dual synchronous motor, the rotor phase passed to the vector rotors of the first and second systems is the same as the phase difference between the first winding and the second winding. It is sufficient to have the phase difference of. This will be apparent to those skilled in the art, for example, in FIG. 11 already reported, and further description thereof will be omitted. Regarding the command converter which is the core of the present invention, there is no change even when the six-phase synchronous motor is targeted as the double synchronous motor.

In the present specification, it has been explained that the previously reported double synchronous motors are roughly classified into three-phase simple synchronous motors, six-phase synchronous motors, and three-phase reverse synchronous motors by using FIGS. 1 to 3. This explanation, paradoxically, means that there may be dual synchronous motors that do not belong to these three major categories. The present invention relates to an electric motor that meets the definition of a double synchronous motor "a double three-phase wound permanent magnet synchronous motor composed of a rotor having a permanent magnet and a stator having two three-phase windings". It should be pointed out that it is applicable as well as the electric motors belonging to the three major categories.

In the embodiment using FIGS. 4 to 10, only copper loss was considered as the loss generated in the dual synchronous motor. The present invention is applied unmodified even when it is necessary to consider copper loss and iron loss at the same time as losses generated in a dual synchronous motor, and the present invention does not exclude this type of motor. I would like to point out that. However, when the present invention is applied to a double synchronous motor in which copper loss and iron loss must be considered at the same time, generally, prior to this, the mathematics of the double synchronous motor in consideration of copper loss and iron loss It is necessary to construct a model (mathematical model corresponding to equations (1) to (3)).

The present invention is suitable for a drive system for a dual synchronous motor that requires a wide range of efficient driving, such as a battery electric vehicle, a fuel cell electric vehicle, a main drive motor of a hybrid electric vehicle, and a high-speed electric motor for home appliances. ..

1 Double synchronous motor 11 Rotator of double synchronous motor 121 First winding of stator of double synchronous motor 122 Second winding of stator of double synchronous motor 2 Power converter 21 Power converter 22 Current detection Instrument 3 Vector controller 31 Command converter 311 Repetitive motor 312 Approximate controller 32 Current control unit 321a Three-phase two-phase converter 321b Two-phase three-phase converter 322a Vector rotor 322b Vector rotor 323 Current controller 324 Phase detection Instrument 325 speed detector

Claims (4)

Two independent three-phase windings with a rotor with permanent magnets and non-superconducting with non-zero winding resistance (two three-phase windings with no connection between the first and second three-phase windings ) Permanent magnet synchronous motor consisting of a stator with) and
A power converter capable of simultaneously supplying different three-phase currents to the two independent three-phase windings,
From the torque command value corresponding, d-axis current command value and a q-axis of each said tracking target serving each said independent three-phase winding current command value of the three-phase current flowing in the independent three-phase windings (for the first three-phase windings A command converter that generates a current command value, a d-axis current command value for the second three-phase winding, and a four-current command value of the q-axis current command value), and each generated current command value is wound with the independent three-phase winding. A vector control device including a current control unit that tracks and controls the current of each of the independent three-phase windings via a power conversion device so that the line currents follow each other.
It is a permanent magnet synchronous motor drive system equipped with
In order to achieve efficient driving over a wide range, the permanent magnet synchronous motor is configured so that the two independent three-phase windings provide winding-derived characteristics that are significantly different from each other, and four current command values are followed and controlled. characterized by being configured to minimize or quasi minimize loss of the permanent magnet synchronous motor in generating, the finger-old conversion unit responsible for the fourth current command value generation due to the currents and the non-zero winding resistance Permanent magnet synchronous motor drive system. It is characterized in that the command conversion unit is configured to generate 4 current command values as a solution of a multivariable simultaneous nonlinear equation of 4 or more variables corresponding to a torque command equivalent value that treats at least 4 current command values as variables. The permanent magnet synchronous motor drive system according to claim 1. The command conversion unit is characterized in that the solution of the multivariable simultaneous nonlinear equations corresponding to the torque command equivalent value is obtained by a real-time iterative calculation for each control cycle to generate a 4-current command value. 2. The permanent magnet synchronous motor drive system according to claim 2. Obtain the 4-current command value corresponding to the torque command equivalent value and bring about loss minimization in advance, and prepare in advance an approximate function or reference table of the 4-current command value with the torque command equivalent value as an argument. The claim is characterized in that the command conversion unit is configured to regeneratively generate the four current command values in real time by an approximate function or a reference table having a torque command equivalent value as an argument for each control cycle. Permanent magnet synchronous motor drive system according to 1 or 2.