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That is, based on the inverter voltage Vc and the coolant temperature ta at the point of the start of the stalled state of the vehicle, the torque limit unit 15 determines whether the requested torque Tn for each of the rotating electrical machines MG 1 and MG 2 at that point is less than or equal to the continuously operable torque Tc steps 22 and Thus, it is determined whether the operation control of the rotating electrical machines MG 1 and MG 2 can be continued continuously with the requested torque Tn even after the stall starting point. Specifically, the torque limit unit 15 refers to the inverter voltage Vc and the coolant temperature ta at that point simultaneously with the determination of the stalled state, determines whether the requested torque Tn is equal to or lower than the continuously operable torque Tc shown in FIG.

In the case where the requested torque Tn is a torque by which the continuous operation is possible step 23 : No , since the load on the rotating electrical machines MG 1 and MG 2 is small even though in the stalled state, the conducted electricity amount of the switching element is small and the heating value is small. Therefore, the control device ECU performs the operation control of the rotating electrical machines MG 1 and MG 2 with the requested torque Tn step With this configuration, the operation control is performed such that the continuously operable torque Tc determined based on the inverter voltage Vc and the coolant temperature ta and the requested torque Tn are compared, and the rotating electrical machine generates the requested torque Tn based on the comparison result.

Thus, the operation control of the rotating electrical machines MG 1 and MG 2 can be performed in accordance with the requested torque Tn determined by the driving condition determination unit 12 while sufficiently protecting the inverter In. As a result, a driving state suitable for the vehicle in which the torque limitation is not applied can be maintained in a state where the protection of the inverter In is ensured. On the other hand, when the requested torque Tn is higher than the continuously operable torque Tc step 23 : Yes , since the load on the rotating electrical machines MG 1 and MG 2 is large, the conducted electricity amount of the switching element is large and the heating value is large.

Therefore, the rotating electrical machines MG 1 and MG 2 are controlled with the requested torque Tn at the stall starting point, for the continuously operable time Ti 0 determined based on the requested torque Tn and the inverter voltage Vc and the coolant temperature ta at that point. Specifically, based on the requested torque Tn at the stall starting point, the inverter voltage Vc, and the coolant temperature ta, the continuously operable time Ti 0 with the requested torque Tn is obtained according to the map as shown in FIG. That is, in the case where the requested torque Tn at the stall starting point is Tn 0 , the inverter voltage is Vc 0 , and the coolant temperature is ta 0 , the continuously operable time is obtained as time 0 from FIG.

Accordingly, the continuously operable time Ti 0 with the requested torque Tn increases as the inverter voltage Vc decreases, and the continuously operable time Ti 0 with the requested torque Tn increases as the coolant temperature ta decreases. The control device ECU controls the rotating electrical machines MG 1 and MG 2 with the requested torque Tn at the stall starting point until the obtained continuously operable time Ti 0 has elapsed steps 25 , 26 , and Specifically, if the timer is zero, the timer starts counting up, and the operation control of the rotating electrical machines MG 1 and MG 2 is performed with the requested torque Tn step 27 until the timer reaches the continuously operable time Ti 0 step 26 : No.

When the timer reaches the continuously operable time Ti 0 step 26 : Yes , the torque limit unit 15 performs the operation control of the rotating electrical machines MG 1 and MG 2 with the limit torque Tr that is the torque reduced from the requested torque Tn. Specifically, the limit torque Tr which is lower than the current requested torque Tn by the reduction amount AT obtained in accordance with the inverter voltage Vc and the coolant temperature ta is determined step As the limit torque Tr, the continuously operable torque Tc described above may be employed.

Obviously, the limit torque Tr may be a torque lower than the continuously operable torque Tc. In this manner, the rotating electrical machines MG 1 and MG 2 are operated with the limit torque Tr in which the torque is reduced. As shown later in FIGS. Next, the change of the torque in the rotating electrical machines MG 1 and MG 2 in a time region in the case where the torque limit control described above is performed will be described.

Condition Monitoring of Rotating Electrical Machines

In the description below, the inverter voltage Vc and the coolant temperature ta will be described separately for an easier understanding. In the drawings, the abscissa shows the time, and the ordinate shows the inverter temperature or the torque. The zero point of the abscissa corresponds to the occurrence point of the stall. In the ordinate, a temperature limit value t 1 is shown as a limit value of the temperature accepted by the inverter.

Further, thin solid lines extending in the horizontal direction show the torques of the rotating electrical machines MG 1 and MG 2 , and show the requested torque Tn and the limit torque Tr. In this embodiment, it is assumed that the temperature increase rate of the switching element forming the inverter In increases as the inverter voltage Vc increases.

In the drawing, a bold dotted line corresponds to a state where the inverter voltage Vc is high and the temperature increase is rapid. In this state, the temperature reaches the temperature limit value t 1 in a short period of time. Thus, the continuously operable time Ti 0 time 1 in this case is short. A bold solid line corresponds to a state where the inverter voltage Vc is low and the temperature increase is moderate.

In this state, the temperature reaches the temperature limit value t 1 at a slower rate. Thus, the continuously operable time Ti 0 time 2 in this case is longer compared to the case where the inverter voltage Vc is high. For example, in the case where the vehicle climbing a slope is brought to the stalled state with an equal balance of a backward force due to its weight and a forward force by the torque of the rotating electrical machine MG 2 and the requested torque Tn at that point is larger than the continuously operable torque Tc with respect to the inverter voltage Vc at that point, the continuously operable time time 1 is obtained and the timer starts to count up.

Basic Concepts of Electrical Rotating Machines L-4.1

Until the timer reaches the continuously operable time time 1 , the torque of the rotating electrical machine is maintained as the requested torque Tn. When the timer reaches the continuously operable time time 1 , a limit torque Tr 1 is determined, and the torque of the rotating electrical machine is gradually decreased to the limit torque Tr 1. A case where the inverter voltage Vc is low follows approximately the same pattern.

However, in the case where the inverter voltage Vc is low, the continuously operable time time 2 increases as described above, and a limit torque Tr 2 is set as a torque higher than the limit torque Tr 1 of the case where the inverter voltage Vc is high but naturally lower than the requested torque Tn. When the continuously operable time time 2 has elapsed, the torque of the rotating electrical machine is decreased from the requested torque Tn to the limit torque Tr.

Thus, driving with the requested torque Tn originally requested for the rotating electrical machine MG 2 is made possible for a longer period of time continuously operable time as the inverter voltage Vc decreases, and the rotating electrical machine MG 2 can further be operated with a torque close to the requested torque Tn also after the continuously operable time Ti 0 corresponding to the requested torque Tn has elapsed.

This means that the time during which a hybrid vehicle can be operated with the requested torque Tn requested for the rotating electrical machine MG 2 while the engine E is operated in a suitable state at the optimum fuel efficiency is significantly increased from the related art, and therefore this is highly advantageous.

In a situation where the coolant temperature ta differs, the temperature of the inverter In generally differs. In the drawing, a bold dotted line shows a state where the coolant temperature ta is high and the temperature of the inverter at the stall occurrence point is high, and a bold solid line shows a state where the coolant temperature ta is low and the temperature of the inverter at the stall occurrence point is low.

In the case where the coolant temperature ta is high, the increase rate of the temperature is faster than in the case where the coolant temperature ta is low. In the state where the coolant temperature ta is high, the temperature reaches the temperature limit value t 1 in a short period of time. Thus, the continuously operable time Ti 0 time 3 in this case is short.

On the other hand, in a situation where the coolant temperature ta is low, the temperature reaches the temperature limit value t 1 at a slower rate since the temperature of the inverter is naturally low. Thus, the continuously operable time Ti 0 time 4 in this case is longer compared to the case where the coolant temperature is high. For example, in the case where the vehicle climbing a slope is brought to the stalled state with an equal balance of a backward force due to its weight and a forward force by the torque of the rotating electrical machine MG 2 , and the requested torque Tn at that point is larger than the continuously operable torque Tc with respect to the coolant temperature ta at that point, the continuously operable time time 3 is obtained step 24 and the timer starts to count up.

Until the timer reaches the continuously operable time time 3 , the torque of the rotating electrical machine is maintained as the requested torque Tn. When the continuously operable time time 3 is reached, a limit torque Tr 3 is determined, and the torque of the rotating electrical machine is gradually decreased to the limit torque Tr 3. A case where the coolant temperature is low follows approximately the same pattern.

However, in the case where the coolant temperature ta is low, the continuously operable time time 4 increases as described above, and a limit torque Tr 4 is set as a torque higher than the limit torque Tr 3 of the case where the coolant temperature ta is high. When the continuously operable time time 4 has elapsed, the torque of the rotating electrical machine is decreased from the requested torque Tn to the limit torque Tr 4.

Thus, driving with the requested torque Tn originally requested for the rotating electrical machine MG 2 is made possible for a longer period of time continuously operable time as the coolant temperature ta decreases, and the rotating electrical machine can further be operated with a torque close to the requested torque Tn also after the continuously operable time Ti 0 corresponding to the requested torque Tn has elapsed.

This means that the time range during which a hybrid vehicle can be operated with the requested torque requested for the rotating electrical machine while the engine is operated in a suitable state at the optimum fuel efficiency is significantly increased from the related art, and therefore this is highly advantageous. Although the inverter voltage Vc and the coolant temperature ta have been separately described above, the torque limit control may be performed in consideration of both of them.

In this case, factors causing different coolant temperatures correspond to different positions of intercepts of temperature on the ordinate side and different inclination angles as shown in FIG. In the temperature behavior shown by a slope line in FIG.

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Magnetomechanical coupled FE simulations of rotating electrical machines

More specifically, the lines of different slopes shown in FIG. Thus, temperature slope lines are drawn with different inclinations in accordance with the inverter voltage. As a result, the time for reaching the temperature limit value is determined in accordance with the temperature slope line. Thus, the torque limit control from the requested torque to the limit torque can be executed, and an appropriate torque is set also for the limit torque in accordance with the inverter voltage and the coolant temperature. However, since the present invention covers systems including a rotating electrical machine of which the drive control is performed by an inverter, the drive source may be only the rotating electrical machine.

That is, it may be applied to an electric vehicle as the vehicle having the so-called rotating electrical machine as the drive source. However, the present invention may be applied to an arbitrary hybrid vehicle including a single rotating electrical machine having a mode of operating as a motor. However, in order to protect the inverter and particularly to protect individual switching elements, the torque limit control may be applied to a system including a control device specifically, the driving condition determination unit which obtains the torque requested for the rotating electrical machine and the torque limit unit of the present invention for the purpose of appropriately protecting the inverter, regardless of the occurrence of the stalled state, even in a normal driving state not in the stalled state.

However, for example, it is also acceptable that a torque within a certain range with respect to the continuously operable torque is set as a torque limit control starting torque, and the torque limit control is started with the torque limit control starting torque as the reference. However, the torque reduction may be performed before the elapse of the continuously operable time.

However, by employing an arbitrary torque lower than the requested torque in the present driving situation as the limit torque, the inverter can be protected to some degree. However, they may be obtained from arithmetic expressions obtained in advance. A rotating electrical machine control system is obtained which can operate a rotating electrical machine with an operation condition required for the rotating electrical machine with minimum torque limitation and which can sufficiently protect an inverter that controls the rotating electrical machine.

According to an exemplary aspect of the invention, the torque limit unit limits reduces the torque of the rotating electrical machine as necessary, and changes a limit of the torque in accordance with the voltage which is also a voltage applied to the rotating electrical machine controlled by the inverter applied to the frequency conversion portion provided in the inverter.

Normally, in a system including a rotating electrical machine, the torque requested for the rotating electrical machine is a torque in accordance with the intended purpose of the employed system. For example, in the case of an electric vehicle, the rotating electrical machine is required to generate a torque that generates a driving force required for the vehicle. In the case of a hybrid vehicle, the rotating electrical machine operating as a motor is required to generate a torque in an amount according to the driving state. According to a study by the inventors of the present invention, the voltage applied to the frequency conversion portion provided in the inverter influences the temperature of the switching element forming the frequency conversion portion.

For example, the inverter voltage closely relates to a continuously operable torque which is a torque that causes no problem in the inverter and consequently the switching element when the rotating electrical machine controlled by the inverter is continuously operated with a predetermined torque, and to a continuously operable time that causes no problem in the inverter when the rotating electrical machine is operated with a torque higher than the continuously operable torque.

As the inverter voltage decreases, the continuously operable torque increases significantly, and the continuously operable time increases significantly in a similar manner. Thus, in the present invention, the form of the torque limit control executed by the torque limit unit depends on the inverter voltage. Accordingly, the rotating electrical machine can be used in a region well before the torque limitation is to be applied in terms of the inverter voltage or the degree of torque limitation can be reduced further more compared to the related art.

Thus, while the inverter is appropriately protected, the rotating electrical machine can be operated in a requested suitable state as much as possible. According to an exemplary aspect of the invention, whether to apply the torque limitation is determined based on the relation with the continuously operable torque, and the continuously operable torque is associated with the inverter voltage.

As described above, in the study conducted by the inventors, the continuously operable torque has a strong relation with the inverter voltage. Thus, by performing the torque limit control when the requested torque is higher than the continuously operable torque obtained in accordance with the inverter voltage, and by operating the rotating electrical machine in accordance with the requested torque when the requested torque is lower than the continuously operable torque, the inverter can be protected in consideration of the inverter voltage and the operation of the rotating electrical machine requested from the control device side can be realized.

According to an exemplary aspect of the invention, the continuously operable torque in accordance with the inverter voltage decrease as the inverter voltage increases. This is because the torque acceptable for the rotating electrical machine decreases since the inverter specifically, each switching element tends to generate heat along with an increase in the inverter voltage.

Thus, the possibility of executing the torque limit control increases as the inverter voltage increases, and decreases as the inverter voltage decreases. However, compared to cases of the related art where the torque limit control has been performed irrespective of the inverter voltage, unnecessary application of the torque limitation can be prevented whereas appropriate torque limitation can be applied when necessary.

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According to an exemplary aspect of the invention, by limiting the torque to the limit torque lower than the requested torque and setting the limit torque as a torque equal to or lower than the continuously operable torque, the heat generation of the inverter can be suppressed to reliably protect the inverter. According to an exemplary aspect of the invention, a reduction amount from the requested torque to the limit torque is changed in accordance with the inverter voltage and that the reduction amount increase as the inverter voltage increases.

As described above, the necessity for the torque limitation increases as the inverter voltage increases.

By causing the reduction amount to depend on the inverter voltage in the case where the torque is reduced to the limit torque lower than the requested torque and increasing the reduction amount as the inverter voltage increases, an increase in the inverter temperature which tends to occur due to high inverter voltage can be well suppressed.

According to an exemplary aspect of the invention, the torque limit control takes a form of decreasing the torque of the rotating electrical machine to the limit torque that is the torque lower than the requested torque after the continuously operable time has elapsed. In this case, the rotating electrical machine is operated with the requested torque until the continuously operable time has elapsed, and the continuously operable time itself is in accordance with the inverter voltage.

In the case where the rotating electrical machine is operated with the requested torque and the requested torque is higher than the continuously operable torque described above, the continuously operable time acceptable for the inverter and consequently the rotating electrical machine with the requested torque naturally has a limit, and the continuously operable time has a close relation with the inverter voltage.

Thus, in this configuration, an accurate torque limit control can be performed by obtaining the continuously operable time in accordance with the inverter voltage and reducing the torque after this time has elapsed.


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In the study conducted by the inventors, compared to the continuously operable time determined based on only the torque value, the temperature of the inverter, and the coolant temperature, the time can be made longer, and a time in which the rotating electrical machine can be operated with a requested torque preferable for the system can be made longer by taking the inverter voltage into consideration as a determination factor.

The continuously operable time decreases as the inverter voltage increases. This is because, when operated at a constant torque, the time decreases as the inverter voltage increases. Further, by employing a configuration in which the torque is continuously changed over time when the torque is reduced from the requested torque to the limit torque, a sudden change in the torque generated by the rotating electrical machine does not occur. Thus, a shock or the like does not occur. According to an exemplary aspect of the invention, by providing the voltage conversion portion in the inverter, it becomes possible to increase the DC voltage from the DC power supply and pass on the DC voltage to the frequency conversion portion to increase the operation range of the rotating electrical machine.

According to an exemplary aspect of the invention, by adding a factor of the cooling capability of the cooling unit to the factor of the inverter voltage when executing the torque limit control, an accurate torque limit control in consideration of both factors can be executed, and the operation state of the rotating electrical machine requested by the system can be ensured while reliably protecting the inverter. Further, by structuring a vehicle drive system including the rotating electrical machine control system described above, and a stall detection unit which detects a stalled state of a vehicle, in which the torque limit unit is operated in a case where the stall detection unit detects that the vehicle is in the stalled state, the problem in the inverter protection which tends to occur at the time of a stall can reliably be avoided.

According to an exemplary aspect of the invention, the driving force on one side distributed by the power distribution mechanism is transmitted to a wheel while the driving force on another side is transmitted to the first rotating electrical machine, and a driving force generated by the second rotating electrical machine is transmitted to the wheel.

The control device determines the rotational speed and the requested torque requested for each of the first rotating electrical machine and the second rotating electrical machine. A larger voltage of a first voltage determined based on the rotational speed and the requested torque requested for the first rotating electrical machine and a second voltage determined based on the rotational speed and the requested torque requested for the second rotating electrical machine is assumed as the inverter voltage.

The vehicle drive system of this configuration includes the drive source for example, the engine other than the pair of rotating electrical machines, and the pair of rotating electrical machines. In a so-called hybrid vehicle which performs power distribution in split form, the operation of the pair of rotating electrical machines is realized in a form satisfying the rotational speed and torque requested for the rotating electrical machines.

Further, a system having a form in which the voltage necessary for each of the pair of rotating electrical machines is obtained by the voltage conversion portion of a single inverter can easily be realized. According to an exemplary aspect of the invention, a hybrid vehicle in which power distribution in split form is performed using a single planetary gear mechanism can easily be realized. Further, also in the hybrid vehicle in which power distribution in split form is performed, the problem in the inverter protection which tends to occur at the time of a stall can reliably be avoided by structuring the vehicle drive system including the stall detection unit which detects the stalled state of the vehicle, in which the torque limit unit is operated in the case where the stall detection unit detects that the vehicle is in the stalled state.

In the present invention, an accurate temperature estimation in correspondence with the inverter voltage can be executed by employing a temperature estimation method for a frequency conversion portion in a rotating electrical machine control system including a DC power supply, a rotating electrical machine, an inverter provided between the DC power supply and the rotating electrical machine to control current flowing in the rotating electrical machine, and a control device which determines a rotational speed as a rotational speed requested for the rotating electrical machine and a requested torque as a torque requested for the rotating electrical machine, in which the inverter is operated based on the rotational speed and the requested torque determined by the control device.

The temperature estimation method includes estimating that a temperature increase rate of a switching element forming the inverter is faster with a higher inverter voltage which is a voltage applied to the frequency conversion portion provided in the inverter. Effective date : Year of fee payment : 4.

A rotating electrical machine includes a DC power supply; a rotating electrical machine; an inverter provided between the DC power supply and the rotating electrical machine to control current flowing in the rotating electrical machine; and a control device that: determines a rotational speed as a rotational speed requested for the rotating electrical machine and a requested torque as a torque requested for the rotating electrical machine; and limits a torque of the rotating electrical machine.

Torque Limit Unit The torque limit unit 15 is a unit that assumes the torque of the rotating electrical machine to be a limit torque Tr lower than a requested torque Tn determined by the driving condition determination unit 12 described above under a predetermined condition.

British Standards Institution - Committee

Start of Torque Limit Control The torque limit unit 15 executes the torque limit control of limiting the torque of the rotating electrical machine in the case where the requested torque Tn requested for the rotating electrical machine is higher than the continuously operable torque Tc as a torque with which the rotating electrical machine can be operated continuously and which is determined based on the inverter voltage and the coolant temperature.

Torque limit control Further, the torque limit control by the torque limit unit 15 causes the torque of the rotating electrical machine to be limited to the limit torque Tr which is a torque lower than the requested torque Tn after the continuously operable time Ti 0 , which is changed in accordance with the inverter voltage Vc and the coolant temperature ta, has elapsed.

Higher Education and Professional Books. Applied Sciences and Other Technologies Books. Enter pincode. Usually delivered in days? Pyrhonen Juha. Primary importance is devoted to Fault Detection and Diagnosis FDI of electrical machine and drive systems in modern industrial automation. The widespread use of Machine Learning techniques has made it possible to replace traditional motor fault detection techniques with more efficient solutions that are capable of early fault recognition by using large amounts of sensory data.

However, the detection of concurrent failures is still a challenge in the presence of disturbing noises or when the multiple faults cause overlapping features. The contribution of this work is to propose a novel methodology using multi-label classification method for simultaneously diagnosing multiple faults and evaluating the fault severity under noisy conditions.

Performance of various multi-label classification models are compared. Current and vibration signals are acquired under normal and fault conditions. The applicability of the proposed method is experimentally validated under diverse fault conditions such as unbalance and misalignment.

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