JP5428234B2 - Rotating electrical machine control system - Google Patents

Description

  The present invention relates to a rotating electrical machine control system, and more particularly to a rotating electrical machine control system that performs output limitation on a rotating electrical machine that is operated by an inverter and has a magnet and a coil, depending on the coil temperature of the rotating electrical machine.

  In a permanent magnet type rotating electrical machine that operates based on electromagnetic conversion between a drive current flowing through a coil and a permanent magnet, the coil generates more heat as the drive current passed through the coil increases. As a result, the temperature of the rotating electrical machine rises. Therefore, in order to prevent or suppress coil burnout, permanent magnet demagnetization, and the like, torque limitation or the like is performed to prevent overheating of the rotating electrical machine.

  For example, in Patent Document 1, as a control device for preventing irreversible demagnetization and coil burnout of a permanent magnet of a synchronous machine that is a permanent magnet motor, the magnet temperature is determined from an armature interlinkage magnetic flux or an induced voltage, which is a conventional method. When estimating, it is pointed out that the accuracy is limited because the coil resistance and d-axis inductance included in the relational expression have temperature dependence. And the higher order component of the armature linkage flux does not depend on the coil resistance and d-axis inductance, and the relationship between the higher order component of the armature linkage flux and the magnet temperature is used to estimate the magnet temperature. It is stated that the output of the synchronous machine is adjusted to prevent irreversible demagnetization, and the coil temperature is estimated from the induced voltage to prevent coil burnout.

JP 2003-235286 A

  In order to prevent overheating of the rotating electrical machine, coil temperature detection is convenient for detecting the temperature of the rotating electrical machine. Therefore, it is possible to prevent overheating of the rotating electrical machine by limiting the torque of the rotating electrical machine according to the temperature detection of the coil.

  Here, inverter circuit technology is widely used for action control of rotating electrical machines. For example, drive control of a rotating electrical machine is performed using a PWM (Pulse Wide Modulation) technique using a carrier frequency and a control target signal. At this time, it may be required to reduce the carrier frequency from the viewpoint of preventing overheating of the inverter, suppressing loss of the system using the rotating electrical machine, or improving fuel consumption. When this carrier frequency is lowered, a ripple component in the output current of the inverter increases, which causes an increase in iron loss.

  Thus, when the carrier frequency of the inverter is reduced, the iron loss increases in the rotating electrical machine, thereby causing the temperature of the permanent magnet itself to rise. In some cases, the temperature of the permanent magnet may be higher than the temperature of the coil. Therefore, it is conceivable to detect the temperature of the permanent magnet separately from the coil temperature. However, if a sensor or the like is provided on the permanent magnet, the magnetic characteristics may change.

  Therefore, in the method of limiting the output of the rotating electrical machine only by monitoring the coil temperature as in the prior art, since the detection cannot be performed even if the temperature of the permanent magnet rises above the coil temperature, the permanent magnet is overheated. , May decrease magnetic force and demagnetize.

  An object of the present invention is to provide a rotating electrical machine control system that can prevent overheating of a coil and a permanent magnet only by monitoring the coil temperature.

A rotating electrical machine control system according to the present invention includes an inverter that operates at a predetermined carrier frequency, a rotating electrical machine that is operated by the inverter and includes a magnet and a coil, and a coil temperature acquisition unit that acquires a coil temperature of the rotating electrical machine. Based on the coil temperature when the carrier frequency is high and the coil temperature is higher than the magnet temperature and the maximum temperature of the rotating electrical machine is determined by the coil temperature using the relationship between the carrier frequency, the coil temperature, and the magnet temperature obtained in advance. When the carrier frequency is low and the magnet temperature is higher than the coil temperature and the maximum temperature of the rotating electrical machine is determined by the magnet temperature, an output limiting unit that limits the output of the rotating electrical machine based on the magnet temperature, the carrier frequency, and the rotation A temperature difference storage unit that stores a temperature difference that is a difference between the coil temperature and the magnet temperature in association with the torque of the electric machine, Means for searching temperature difference from temperature difference storage unit using carrier frequency and torque as conditions as search keys, estimating magnet temperature based on searched temperature difference and coil temperature, and acquiring estimated magnet temperature And a comparison unit that extracts a higher temperature by comparing the coil temperature, and the output limiting unit performs output limitation of the rotating electrical machine based on the higher temperature by the comparison unit. And

Further, in the rotating electric machine control system according to the present invention, have group Dzu the relationship between the previously obtained carrier frequency and coil temperature and the magnet temperature, if the maximum temperature of the rotary electric machine at a high coil temperatures carrier frequency is determined in the coil If the allowable temperature limit is the temperature at which the output of the rotating electrical machine starts to be limited and the carrier frequency is low and the maximum temperature of the rotating electrical machine is determined at the magnet temperature, the temperature difference of the rotating electrical machine is the difference between the coil temperature and the magnet temperature . It is preferable that a restriction start temperature storage unit that stores a temperature at which output restriction is started is lowered and the output restriction unit changes a temperature at which output restriction of the rotating electrical machine is started according to the carrier frequency.

  With the above configuration, the rotating electrical machine control system acquires the magnet temperature based on the carrier frequency and the coil temperature, and limits the output of the rotating electrical machine in consideration of the magnet temperature in addition to the coil temperature. Thus, overheating of the coil and the magnet can be prevented by considering the influence of the carrier frequency in addition to the coil temperature for the output restriction of the rotating electrical machine.

  In the rotating electrical machine control system, the temperature difference that is the difference between the coil temperature and the magnet temperature is stored in association with the carrier frequency and the torque of the rotating electrical machine, and the magnet temperature is determined based on the temperature difference and the coil temperature. The estimated magnet temperature is compared with the acquired coil temperature to extract the higher temperature, and the output of the rotating electrical machine is limited based on the higher temperature. Thereby, overheating of the coil and the magnet can be prevented.

  Further, in the rotating electrical machine control system, based on the relationship between the carrier frequency, the coil temperature, and the magnet temperature obtained in advance, the temperature at which the output restriction of the rotating electrical machine related to the carrier frequency is started is stored, and according to the carrier frequency. To change the temperature at which the output restriction of the rotating electrical machine is started. Thereby, overheating of the coil and the magnet can be prevented.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, it is assumed that one motor / generator having a motor function and a generator function is used as the rotating electrical machine connected to the power supply circuit, but two motors / generators may be used. In that case, it is possible to use one rotating electrical machine having only a motor function and one rotating electrical machine having only a generator function.

  The power supply circuit connected to the rotating electrical machine is described as using a power storage device, a voltage converter, a smoothing capacitor, and an inverter, but other elements may be added as necessary. For example, it is good also as a structure which has a system main relay, a DC / DC converter, a low voltage power supply, etc.

  The numerical values such as carrier frequency, torque, temperature difference between the coil temperature and the magnet temperature described below are examples for explanation, and can be appropriately changed according to the specifications of the rotating electrical machine. For example, although the following description will be made using typically 5 kHz and 1 kHz as carrier frequencies, other frequencies may be used as a matter of course.

  Below, the same code | symbol is attached | subjected to the same element in all the drawings, and the overlapping description is abbreviate | omitted. In the description in the text, the symbols described before are used as necessary.

  FIG. 1 is a diagram illustrating a rotating electrical machine control system 10 extracted from a hybrid vehicle control system that controls the operation of a hybrid vehicle equipped with a rotating electrical machine. The rotating electrical machine control system 10 has a function of controlling the operation of the rotating electrical machine in accordance with a required torque given by an accelerator or the like in relation to the traveling of the vehicle. It has a function.

  The rotating electrical machine control system 10 includes a power supply circuit 12, a rotating electrical machine 14, an inverter ECU (Electric Control Unit) 40 that controls the operation of an inverter 24 included in the power supply circuit 12, and the operations of these components as a whole. The control part 50 controlled as follows is comprised.

  The power supply circuit 12 includes a power storage device 16, a power storage device-side smoothing capacitor 18, a voltage converter 20, an inverter-side smoothing capacitor 22, and an inverter 24.

  The power storage device 16 is a chargeable / dischargeable high voltage secondary battery. As the power storage device 16, for example, a lithium ion assembled battery or a nickel hydride assembled battery having a terminal voltage of about 200 V, a capacitor, or the like can be used.

  The voltage converter 20 is a circuit that is disposed between the power storage device 16 and the inverter 24 and has a voltage conversion function. The voltage converter 20 can include a reactor and a switching element that operates under the control of the control unit 50. As the voltage conversion function, the voltage on the power storage device side is boosted using the reactor energy storage action and supplied to the inverter side, and the power from the inverter side is stepped down to the power storage device side and supplied as charging power It has a step-down function. Note that the present invention can be applied even when the voltage converter or the like does not have a boosting function.

A power storage device side smoothing capacitor 18 provided between the power storage device 16 and the voltage converter 20;
The inverter-side smoothing capacitor 22 provided between the voltage converter 20 and the inverter 24 is a capacitor having a function of suppressing and smoothing fluctuations in voltage and current.

  The inverter 24 is a circuit that performs power conversion between AC power and DC power. The inverter 24 includes a plurality of switching elements that operate under the control of the control unit 50. In FIG. 1, corresponding to each of the three-phase coils 30 of the rotating electrical machine 14, a portion called an upper arm in which the switching element and the diode are connected in parallel, and similarly, a lower part in which the switching element and the diode are connected in parallel. The inverter 24 is shown as a configuration in which three sets of circuits in which parts called arms are connected in series are connected in parallel.

  The inverter 24 is controlled to operate under the inverter ECU 40. In the example of FIG. 1, the respective switching signals for the six switching elements and the carrier frequency f are supplied from the inverter ECU 40, whereby a desired three-phase output current is output as a three-phase drive current for the rotating electrical machine 14.

  The inverter 24 can perform both AC-DC conversion and DC-AC conversion. When the rotating electrical machine 14 functions as a generator, the inverter 24 has an AC / DC conversion function that converts AC three-phase regenerative power from the rotating electrical machine 14 into DC power and supplies it as a charging current to the power storage device side. Further, in the case where the rotating electrical machine 14 functions as a motor, when the vehicle is in power running, the inverter 24 converts the DC power from the power storage device side into AC three-phase driving power and supplies the rotating electrical machine 14 as driving power. In addition, when the vehicle is braking, it has an AC / DC conversion function that converts AC three-phase regenerative power from the rotating electrical machine 14 into DC power and supplies it as a charging current to the power storage device.

  The rotating electrical machine 14 is a motor generator (MG) mounted on the vehicle, and functions as a motor when electric power is supplied from the power supply circuit 12, and is driven by an engine (not shown) or when the vehicle is braked. This is a three-phase synchronous rotating electric machine that functions as a generator. Of course, in addition to this, the present invention can be applied to, for example, a single-phase synchronous rotating electric machine.

The rotating electrical machine 14 includes a stator around which a three-phase coil is wound and a rotor having a permanent magnet. For example, when functioning as a motor, each phase current of the three-phase drive current output from the inverter 24 is supplied to each phase coil 30 of the three-phase coil of the stator to generate a rotating magnetic field in the stator. Due to the cooperative action of the rotating magnetic field and the permanent magnet, a rotating torque is generated in the permanent magnet, that is, the rotor, and a desired torque _Tq is output from the output shaft of the rotor to the axle of the vehicle.

In this case, the coil 30, the coil thermometer is provided for detecting the coil temperature T _C. As the coil thermometer, for example, a temperature sensor such as a thermistor can be used. The coil thermometer may be provided in only one representative coil among the plurality of coils, or may be provided in each of two or more coils.

The inverter ECU 40 is a control device having a function of controlling the operation of the inverter 24 and can substantially control the operation of the rotating electrical machine 14. The inverter ECU 40 first receives a command for the torque T _q of the rotating electrical machine 14 and a command for the rotational speed N from the control unit 50. Then, the six switching operations of the inverter 24 are performed so that the inverter 24 outputs a three-phase drive current for operating the rotating electrical machine 14 at the torque T _q and the rotation speed N under a preset carrier frequency f. A switching signal for the element is generated. In this way, the inverter ECU 40 controls the operation of the inverter 24.

  Here, the carrier frequency f set in the inverter ECU 40 is preferably as low as possible from the viewpoint of preventing overheating of the inverter 24 and improving the fuel efficiency of the hybrid vehicle using the rotating electrical machine 14. However, when the carrier frequency f is set to a low frequency, the ripple component superimposed on the drive current I output from the inverter 24 increases accordingly. As a result, the iron loss in the operation of the rotating electrical machine 14 increases, and the temperature of the magnet rises.

The state of the relationship between the coil temperature T _C and the magnet temperature T _M with respect to the carrier frequency f will be described with reference to FIGS. FIG. 2 is a diagram qualitatively explaining an example of the structure related to the coil and magnet of the rotating electrical machine 14 and the state of the ripple component superimposed on the drive current I when the carrier frequency f is changed. FIG. 3 is a diagram qualitatively explaining the relationship between the coil temperature T _C and the magnet temperature T _M when the carrier frequency f is changed.

  Although FIG. 2 is an example, the upper part shows a state where the carrier frequency f = 5 kHz, and the lower part shows a state where the carrier frequency f is reduced to f = 1 kHz. In each of the drawings, the diagram on the right side is a cross-sectional view in a plane perpendicular to the axial direction of the rotating electrical machine 14. As shown here, in the rotating electrical machine 14, each phase coil 30 of a three-phase coil is wound around a cylindrical stator 26. A rotor 28 is disposed in the inner circumferential space of the cylindrical stator 26. A magnet 32 is disposed on the outer periphery of the rotor 28.

As described above, each phase drive current I is supplied from the inverter 24 to each phase coil 30 of the three-phase coil, thereby generating a rotating magnetic field as indicated by an arrow on the stator 26. Due to the electromagnetic cooperative action between the rotating magnetic field and the magnet 32 of the rotor 28, the rotor 28 generates a rotational torque indicated by an arrow, which is output from the output shaft of the rotating electrical machine 14 as a torque _Tq .

The state of the waveform of the drive current I output from the inverter 24 is shown on the left side in each figure. The diagram on the left side of each stage in FIG. 2 shows how the amplitude of the ripple component increases when the carrier frequency f in the inverter 24 becomes lower than when the carrier frequency f is higher. And the temperature of the magnet 32 rises with the increase in this ripple component. Therefore, as shown on the right side of each stage in FIG. 2, when the carrier frequency f is high, even if the coil temperature T _C is higher than the magnet temperature T _M , the coil temperature T _The magnet temperature _TM is higher than _C.

FIG. 3 is a diagram illustrating changes in the coil temperature T _C and the magnet temperature T _M with respect to the torque T _q of the rotating electrical machine 14 when the carrier frequency f is high and low. As shown in these figures, both the coil temperature T _C and the magnet temperature T _M increase as the torque T _q of the rotating electrical machine 14 increases. As shown in the left diagram of FIG. 3, when the carrier frequency f is high, the coil temperature T _C is higher than the magnet temperature T _M. On the other hand, as shown in the diagram on the right side of FIG. 3, when the carrier frequency f decreases, the magnet temperature T _M becomes higher than the coil temperature T _C.

Thus, with the change of the carrier frequency f, the coil temperature T _C and the magnet temperature T _M show different behaviors. Therefore, simply detecting the temperature of the coil 30 may overlook the temperature rise of the magnet 32, and the overheating of the rotating electrical machine 14 cannot be prevented.

Referring back to FIG. 1 again, the accelerator 42 connected to the control unit 50 is a means for acquiring a request for acceleration or the like from the user when the hybrid vehicle is traveling. Specifically, by acquiring the accelerator depression degree by means for detecting the accelerator depression degree, and transmitting the accelerator depression degree to the control unit 50 through an appropriate signal line, the control unit 50 determines the degree of torque required by the user. You can get it. Based on the torque requested by the user, control unit 50 outputs a command for torque _Tq of rotating electrical machine 14 to inverter ECU 40.

The storage unit 44 connected to the control unit 50 has a function of storing a program and the like, but particularly has a function of storing a map used for operation control of the rotating electrical machine 14 here. One of the stored maps is a temperature difference map 46 relating to the temperature difference between the coil temperature T _C and the magnet temperature T _M. Another map is a limit start temperature map 48 related to the limit start temperature T ₀ of the carrier frequency f and the output of the rotating electrical machine 14.

The temperature difference map 46 is obtained by mapping the relationship shown in FIG. 3 in advance. The temperature difference map 46 stores a temperature difference ΔT = T _M −T _C which is a difference between the coil temperature T _C and the magnet temperature T _M in association with the carrier frequency f and the torque T _q of the rotating electrical machine 14. Temperature difference map 46, as a search and a torque T _q of the carrier frequency f rotary electric machine 14 key, as long as it can find the temperature difference [Delta] T, another map format, the carrier frequency f and the torque T _q and the temperature difference A look-up table format in which the relationship with ΔT is tabulated may be used, or a relationship equation format in which the temperature difference ΔT is output by inputting the carrier frequency f and the torque T _q of the rotating electrical machine 14 may be used.

The limit start temperature map 48 stores a limit start temperature T ₀ for starting output limitation of the rotating electrical machine 14 in association with the carrier frequency f. The limit start temperature T ₀ is a temperature lower than that, and the torque T _q output from the rotating electrical machine 14 is set as a predetermined maximum allowable torque. When the temperature exceeds the limit start temperature T ₀ , This is a temperature that limits the torque T _q output from the rotating electrical machine 14 to a gradually lower torque from the allowable torque. That is, when the limit start temperature T ₀ is exceeded, the upper limit of the torque T _{q that} can be output by the rotating electrical machine 14 is limited to be small. Specifically, the magnitude of the three-phase drive current output from the inverter 24 is limited. As a result, overheating of the rotating electrical machine 14 is prevented.

The limit start temperature T ₀ can be obtained in advance based on the characteristics of the rotating electrical machine 14 and the data shown in FIG. That is, higher carrier frequency f, when the coil temperature T _C determined maximum temperature of the rotary electric machine 14 may be an allowable limit temperature of the coil temperature T _C which has been conventionally used as limit start temperature T ₀ . Carrier frequency f is low, when a magnet temperature T _M maximum temperature of the rotary electric machine 14 is determined, instead of the acceptable limits the temperature of the coil temperature T _C which has been conventionally used, the coil temperature T _C and the magnet temperature T _M difference amount corresponding to the temperature difference ΔT = T _M -T _C is the assumed to lower the limit start temperature T _0. In this way, the limit start temperature T ₀ can be obtained in advance for each carrier frequency f.

The restriction start temperature map 48 only needs to be able to search for the restriction start temperature T ₀ using the carrier frequency f as a search key. In addition to the map format, the relationship between the carrier frequency f and the restriction start temperature T ₀ is tabulated. A look-up table format may be used, or a relational expression format that outputs the limit start temperature T ₀ by inputting the carrier frequency f may be used.

  In FIG. 1, a control unit 50 is a general ECU having a function of controlling the operation of each element constituting the hybrid vehicle as a whole. The control unit 50 has a function of controlling the operation of the rotating electrical machine 14 in accordance with the required torque given by the accelerator 42 in relation to the traveling of the vehicle, but here, in particular, a function of performing an operation control related to preventing overheating of the rotating electrical machine 14. Have Such a control unit 50 can be configured by a computer or the like suitable for mounting on a vehicle. Note that the function of the inverter ECU 40 may be part of the function of the control unit 50, and the storage unit 44 may be built in the control unit 50.

Control unit 50, based on the carrier frequency f and the coil temperature T _C, configured to include an output limiting module 52 for output limitation of the rotary electric machine 14. Further, for one of the functions executed by the output limiting module 52, the temperature difference ΔT is searched from the temperature difference map 46 using the carrier frequency f and the torque T _q of the rotating electrical machine 14 as search keys, and the searched temperature difference ΔT. And a magnet temperature estimation module 54 for estimating the magnet temperature T _M based on the coil temperature T _C.

  Such a function can be realized by software, specifically, by executing a rotating electrical machine control program in the hybrid vehicle control program. Some of these functions may be realized by hardware.

There are two types of functions executed by the output restriction module 52 of the control unit 50, and overheating of the rotating electrical machine 14 can be effectively prevented regardless of which function is executed. Hereinafter, as a first function, the magnet temperature T _M is estimated based on the temperature difference ΔT = T _M −T _C stored in advance in the storage unit 44, and the output of the rotating electrical machine 14 is limited based on the estimated temperature. This will be described first, and then, as a second function, it will be described that the output of the rotating electrical machine 14 is directly limited based on the carrier frequency f.

  4 and 5 are diagrams for explaining the first function of output restriction. FIG. 4 is a diagram showing a flow of data accompanying the output restriction process, and FIG. 5 is a diagram showing a state of output restriction.

In FIG. 4, data of the currently set carrier frequency f is transmitted from the inverter 24 to the control unit 50. The data from the coil thermometer provided in the coil 30 of the rotating electrical machine 14 of the coil temperature T _C is transmitted to the control unit 50. The control unit 50 refers to the temperature difference map 46 in the storage unit 44 and searches for the temperature difference ΔT = T _M −T _C. This search is performed by acquiring the corresponding temperature difference ΔT using the transmitted carrier frequency f and the current torque T _q of the rotating electrical machine 14 ascertained by the control unit 50 as search keys. Then, the control unit 50 estimates the magnet temperature T _M as T _M = ΔT + T _C from the acquired ΔT and the transmitted coil temperature T _C. This procedure is executed by the function of the magnet temperature estimation module 54 of the control unit 50.

Data of the estimated magnet temperature T _M is output to Hi select section 56. The Hi select unit 56 is also supplied with the coil temperature T _C data transmitted from the rotating electrical machine 14. Hi select section 56 has a function of which of the input T _M and T _C is determined whether a high temperature, and outputs the temperature to extract the higher temperature. Based on the extracted higher temperature, the output of the rotating electrical machine 14 is limited.

As an example, it is assumed that T _C = 140 ° C., the carrier frequency f = 1 kHz, and the torque T _q of the rotating electrical machine 14 is 150 Nm. According to the temperature difference map 46 shown in FIG. 4, ΔT = + 5 ° C. That is, by reducing the carrier frequency f, the magnet temperature T _M is higher than the coil temperature T _C. The magnet temperature T _M is estimated to be + 5 ° C. + 140 ° C. = 145 ° C. The Hi selection unit 56 compares T _C = 140 ° C. with T _M = 145 ° C. and outputs the temperature on the high temperature side. In this case, T _M = 145 ° C. is output.

FIG. 5 is a diagram illustrating a state in which output restriction is performed at the extracted higher temperature. Here, the horizontal axis represents the coil temperature T _C , and the vertical axis represents the torque T _q of the rotating electrical machine 14. The left diagram shows the case where the carrier frequency f = 5 kHz, and the right diagram shows the case where the carrier frequency is changed to f = 1 kHz.

As described above, the diagram on the left is a case where the carrier frequency is sufficiently high such that f = 5 kHz, and the coil temperature T _C is higher than the magnet temperature T _M. At this time, the output is limited based on the coil temperature T _C as in the prior art. That is, the limit start temperature T ₀ that is the temperature at which the output limit starts is set as T _C. The diagram on the right side shows the case where the carrier frequency f = 1 kHz and the magnet temperature T _M is higher than the coil temperature T _C. At this time, the output is limited based on the estimated magnet temperature T _M instead of the coil temperature T _C actually measured by the coil thermometer. That is, the restriction start temperature T ₀ that is the temperature at which output restriction starts is defined as T _M.

Thus, according to the first function of the output limiting module 52 of the control unit 50, the magnet temperature T _M is estimated based on the temperature difference ΔT = T _M −T _C stored in advance in the storage unit 44. Then, the magnet temperature T _M is compared with the coil temperature T _C, and the output of the rotating electrical machine 14 is limited using the higher temperature as the limit start temperature. Thereby, even if the carrier frequency f is changed, overheating of the coil 30 and the magnet 32 can be prevented.

6 and 7 are diagrams for explaining the second function of output restriction. Figure 6 is similar to FIG. 4 is a diagram showing the flow of data associated with the output restriction processing, FIG. 7, similarly to FIG. 5, it is a diagram showing a state of the output limit.

In FIG. 6, data of the currently set carrier frequency f is transmitted from the inverter 24 to the control unit 50. The data from the coil thermometer provided in the coil 30 of the rotating electrical machine 14 of the coil temperature T _C is transmitted to the control unit 50. Up to this point, the contents are the same as those described in FIG.

The controller 50 refers to the limit start temperature map 48 in the storage unit 44 and searches for the limit start temperature T ₀ corresponding to the carrier frequency f. This search is performed by obtaining the corresponding limit start temperature T ₀ using the transmitted carrier frequency f as a search key. Based on the acquired limit start temperature T ₀ , the output of the rotating electrical machine 14 is limited.

As an example, if the carrier frequency f = 5 kHz, T ₀ = 150 ° C. according to the limit start temperature map 48 shown in FIG. On the other hand, when the carrier frequency f = 1 kHz, T ₀ = 120 ° C.

FIG. 7 is a diagram illustrating a state in which output restriction is performed based on the obtained restriction start temperature T ₀ . The figure on the left is the case where the carrier frequency f = 5 kHz, the coil temperature T _C is higher than the magnet temperature T _M , and the limit start temperature T ₀ is 150 ° C. At this time, it means that the limit start temperature T ₀ on the basis of coil temperature T _C is determined, in practice, the output restriction based on the coil temperature T _C is performed. The diagram on the right side shows the case where the carrier frequency f = 1 kHz, the magnet temperature T _M is higher than the coil temperature T _C , and the limit start temperature T ₀ is 120 ° C. At this time, since the limit start temperature T ₀ will be defined on the basis of the estimated magnet temperature T _M, in practice, the output restriction based on the estimated magnet temperature T _M is performed.

Thus, according to the second function of the output restriction module 52 of the control unit 50, the output of the rotating electrical machine 14 is based on the restriction start temperature T ₀ for each carrier frequency f stored in the storage unit 44 in advance. Restrictions are made. Thereby, even if the carrier frequency f is changed, overheating of the coil 30 and the magnet 32 can be prevented.

It is a figure which shows the structure of the rotary electric machine control system of embodiment which concerns on this invention. It is a figure explaining the example of the structure relevant to the coil and magnet of a rotary electric machine, and the mode of the ripple component superimposed on the drive current when a carrier frequency is changed. It is a figure explaining qualitatively the relationship between coil temperature when changing a carrier frequency, and magnet temperature. In embodiment which concerns on this invention, it is a figure which shows the data flow about the 1st function of output restrictions. In embodiment which concerns on this invention, it is a figure explaining the mode of output restriction | limiting about the 1st function of output restriction | limiting. In embodiment concerning this invention, it is a figure which shows the data flow about the 2nd function of output restriction | limiting. In embodiment which concerns on this invention, it is a figure explaining the mode of output restriction | limiting about the 2nd function of output restriction | limiting.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Rotating electrical machine control system, 12 Power supply circuit, 14 Rotating electrical machine, 16 Power storage device, 18 Power storage device side smoothing capacitor, 20 Voltage converter, 22 Inverter side smoothing capacitor, 24 Inverter, 26 Stator, 28 Rotor, 30 Coil, 32 Magnet , 40 inverter ECU, 42 accelerator, 44 storage unit, 46 temperature difference map, 48 limit start temperature map, 50 control unit, 52 output limit module, 54 magnet temperature estimation module, 56 Hi select unit.

Claims (1)

An inverter operating at a predetermined carrier frequency;
A rotating electric machine operated by an inverter and having a magnet and a coil;
Coil temperature acquisition means for acquiring the coil temperature of the rotating electrical machine;
Based on the coil temperature, when the carrier frequency is high and the coil temperature is higher than the magnet temperature and the maximum temperature of the rotating electrical machine is determined by the coil temperature, using the relationship between the carrier frequency, the coil temperature, and the magnet temperature obtained in advance, When the carrier frequency is low and the magnet temperature is higher than the coil temperature and the maximum temperature of the rotating electrical machine is determined by the magnet temperature, an output limiting unit that limits the output of the rotating electrical machine based on the magnet temperature;
A temperature difference storage unit that stores a temperature difference that is a difference between the coil temperature and the magnet temperature in association with the carrier frequency and the torque of the rotating electrical machine;
Means for searching the temperature difference from the temperature difference storage unit using the carrier frequency and torque which are the operating conditions of the rotating electrical machine as search keys, and estimating the magnet temperature based on the searched temperature difference and the coil temperature;
A comparing means for comparing the estimated magnet temperature with the acquired coil temperature and extracting the higher temperature;
With
The output limiting unit limits the output of the rotating electrical machine based on the temperature set higher by the comparison means .

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