JP4701627B2 - Electric motor control device - Google Patents

Description

  The present invention relates to an electric motor control device that uses a prime mover as a power source and performs variable speed control of an electric motor using a generator and a semiconductor power conversion device.

Conventionally, when variable speed control of an electric motor using a semiconductor power converter, when protecting equipment against an overload exceeding a normal load, the output voltage and output current of the power converter, that is, the voltage and current of the electric motor, or This is achieved by limiting the voltage and torque of the motor to predetermined values.
This is probably because if the voltage or torque of the motor is limited, the input power input from the power source is also limited to a predetermined value, and it is not necessary to limit the input power directly. The reason for this will be described next.

  When variable speed control of an electric motor is performed using a semiconductor power converter, the relationship between the motor terminal voltage and the maximum torque that can be output with respect to the rotational speed generally has the characteristics shown in FIGS. Here, a solid line indicates a continuous rating characteristic, and a broken line indicates a short-time rating (for example, 1 minute) overload characteristic. Below is a supplementary explanation of these characteristics. For convenience of description, continuous rated torque and output are described as 100%, and short-time overload torque and output are described as 200%.

The magnetic flux of the electric motor is desirably controlled to a value close to the limit that leads to magnetic saturation, so that the magnetic flux can be maximized to reduce the size of the electric motor. Since the terminal voltage of the electric motor is almost proportional to the relation between the magnetic flux and the speed, if the magnetic flux is constant, the rotational speed and the terminal voltage are almost proportional.
The rotational speed Nb when the terminal voltage of the motor reaches the rated voltage is called the base speed, and the maximum voltage that can be output by the power converter is equal to the rated voltage or higher by several% to 10%. It is common to design. When the base rotational speed is increased from the base speed, the terminal voltage is controlled to be substantially constant by weakening the magnetic flux in inverse proportion to the rotational speed. This control is called field-weakening control or field-weakening control. As a result, the terminal voltage and magnetic flux characteristics of the motor are as shown in FIG.

  If the magnetic flux of the electric motor is regarded as a vector, the torque of the electric motor is proportional to the product of the magnetic flux and a current component orthogonal thereto. This current component is called a torque current in the case of an AC motor. In AC motor vector control, torque is controlled by changing torque current. The output of the motor is proportional to the product of torque and rotational speed. As a result, the torque and motor output characteristics with respect to the rotational speed are as shown in FIG. As shown in the figure, the output of the motor is proportional to the rotational speed up to the base speed Nb, and is controlled to be constant above the base speed Nb.

  When the power supply voltage falls below a predetermined value, the maximum voltage that can be outputted by the power converter is lowered. Therefore, the desired voltage cannot be outputted, and the output voltage may be distorted in a square wave shape to cause abnormal vibration and noise. This problem may be designed in advance so that the maximum voltage that can be output by the power converter is high, but there is a disadvantage that the power converter becomes large and expensive. As a method for solving this, for example, the technical contents of Patent Document 1 and Patent Document 2 have been proposed. Although the means are different in the methods proposed in the patent documents 1 and 2, they coincide in that the terminal voltage of the motor is lowered as a result of weakening the magnetic flux of the motor at high speed.

  Examples of characteristics in this case are shown in FIGS. Here, for the sake of simplicity, only the case of short-time rating is shown, the broken line represents the maximum 200% torque and 200% output characteristics, and the thick solid line represents the characteristics when the power supply voltage decreases. As shown in FIG. 12, only when the power supply voltage falls below a predetermined value, the effective value of the terminal voltage is lowered, and the disadvantage that the output voltage is distorted into a square wave is solved. As a result, the output of the electric motor becomes like the thick line in FIG. 13, and the upper limit of the output decreases. That is, when the power supply voltage decreases, the upper limit of the output of the electric motor also decreases, so that it is possible to avoid an excessive overload state due to an excessive input current of the power converter.

FIG. 14 is a block diagram showing a configuration of a variable speed device for an electric motor when a conventional prime mover is used as a power source. However, the prime mover is a part such as a car engine. For example, a prime mover is a machine that generates power by changing various energy existing in nature into mechanical work such as reciprocating motion and rotational motion. It can be said.
The generator 2 coupled to the prime mover 1 generates AC power corresponding to the power of the prime mover 1, and the AC power is rectified by a rectifier (DC power supply) 3 and converted to DC power. The AC motor 5 is driven and controlled while the DC power is converted into an AC signal such as a sine wave by the inverter 4.

  By the way, there is an application that requires a large torque at a low speed, and an ice propulsion ship electric propulsion is one example. FIG. 15 and FIG. 16 show examples of characteristics of electric propulsion for icebreakers. The solid line is the continuous rating and the broken line is the short-time rated overload characteristics. These characteristics are different from the case of FIG. 10 and FIG. 11 described above, in which a short-time overload is required only at a base speed Nb or less. The icebreaker requires a large torque during icebreaking, but it cannot be crushed due to the characteristics of ice torque at high speed rotation, and has torque characteristics corresponding to breaking ice at medium speed or less.

It should be noted that the short-time overload torque increases in inverse proportion to the rotational speed from the base speed Nb. In this case, although the upper limit of the torque is 200%, as described above, the output of the motor is proportional to the product of the torque and the rotational speed, so the output of the motor does not exceed the 100% output that is the continuous rating. Correspondingly, the output of the prime mover and generator will not exceed the continuous rating. As a result, the prime mover and the generator do not need overload characteristics, and the prime mover and the generator can be miniaturized.
Japanese Patent Laid-Open No. 5-260762 Japanese Patent Application Laid-Open No. 10-164883

  By the way, in the conventional motor control device, when the rotational speed of the prime mover 1 falls below a predetermined value, the voltage of the generator 2 also falls accordingly. Alternatively, when there is a sudden load fluctuation, the voltage of the generator 2 is lowered transiently. In the methods proposed in Patent Document 1 and Patent Document 2, the output voltage of the inverter is square by reducing the upper limit of the terminal voltage of the electric motor 5 only when the voltage of the generator 2 drops below a predetermined value. It is possible to solve the drawbacks of undulating distortion.

  However, applications having the characteristics shown in FIGS. 15 and 16, for example, applications where the motor 5 requires a large torque at a low speed, such as icebreaker electric propulsion, in other words, the motor 5 is short only when the motor speed is lower than the base speed Nb. In applications where overload characteristics are required, the disadvantage that the prime mover 1 and the generator 2 are overloaded when the rotational speed of the prime mover 1 and the voltage of the generator 2 are reduced below a predetermined value cannot be solved. In other words, in applications where the motor requires a large torque at a low speed, if the rotational speed of the prime mover 1 or the voltage of the generator 2 falls below a predetermined value, the prime mover 1 or the generator 2 is overloaded. .

  The reason for this will be described with reference to FIG. In FIG. 17, only the torque and output characteristics at the time of short-time rating are shown for simplicity, the broken line is the normal characteristic, and the thick solid line is the characteristic when the power supply voltage is lowered. For example, when the power supply voltage drops to the rated 80% voltage, the conventional control performs the flux weakening control from about 80% of the base speed Nb described above. In this case, the output is limited to 80% or less at 80% or more of the base speed Nb, but is 100% at 60% or 80% of the base speed Nb. When the power supply voltage is 80% of the rating and the output is 100%, the power supply current is about 125% of the rating, and the power supply is overloaded.

  On the other hand, the prime mover 1 has a characteristic close to a constant torque characteristic, and if the rotational speed of the prime mover 1 decreases, the output limit also decreases. Therefore, it is desirable to limit the output in accordance with the rotational speed of the prime mover 1, but the conventional control method cannot restrict the output of the motor 5, that is, the upper limit of the output of the prime mover 1, so the output has a predetermined upper limit. When the value exceeds the value, the rotational speed of the prime mover 1 suddenly stalls and stops. Since the electric motor 5 is also rapidly stopped according to the operation of the prime mover 1, there is a problem in that it may interfere with a device in which the electric motor 5 is used.

  The present invention has been made in view of such problems, and in applications where the motor requires a large torque at a low speed, even when the rotational speed of the prime mover or the voltage of the generator falls below a predetermined value, the prime mover or The generator can be prevented from being overloaded, and the upper limit of the output of the prime mover can be limited to prevent a rapid stop of the motor in response to a sudden stall stop of the prime mover. It is an object of the present invention to provide an electric motor control device that can eliminate an obstacle to applied equipment.

In order to achieve the above object, an electric motor control apparatus according to claim 1 of the present invention includes a prime mover that is a power source, a generator that generates alternating current power according to the power of the prime mover, and the alternating current power of the generator. An electric motor speed sensor for detecting the rotational speed of the motor; and a rotational speed of the prime mover. An absolute value function device for calculating an absolute value of the motor rotation speed detected by the motor speed sensor, and an absolute value of the motor rotation speed output from the absolute value function device as a magnetic flux command source signal. in a divider for dividing, and means for calculating a composed magnetic flux command value in a multiplier for multiplying the rotation speed of the prime mover detected by the engine speed sensor to the output of該除adder, A speed regulator to which a deviation between the degree set value and the motor rotation speed detected by the motor speed sensor is input, an upper limiter for limiting an upper limit of a torque command value output from the speed regulator with a torque limit value, A divider for calculating a torque current command value by dividing a torque command value output from the upper limiter with an upper limit limited by the magnetic flux command value; and a device in which the motor is used with an absolute value of the motor rotation speed. a divider for dividing the first rotational speed that is determined to meet the specifications, by multiplying the rotation speed of the detected prime mover by said prime mover speed sensor to the output of該除adder calculates the torque limit value And a means for calculating a torque current command value constituted by a multiplier and a means for driving the power converter based on the magnetic flux command value and the torque current command value. .

  According to this configuration, the upper limit of the torque of the electric motor is inversely proportional to the speed of the electric motor and limited in proportion to the rotational speed of the prime mover, so that the prime mover can be prevented from being overloaded. Furthermore, since the magnetic flux of the motor is inversely proportional to the rotational speed of the motor and controlled in proportion to the rotational speed of the prime mover, it is possible to avoid distortion of the motor voltage due to a voltage drop of the generator.

According to a second aspect of the present invention, there is provided an electric motor control apparatus comprising: a prime mover that is a power source; a generator that generates alternating current power according to the power of the prime mover; and the alternating current power of the generator is converted to direct current power. In an electric motor control device having a power conversion device that converts the DC power into electric power for driving and controlling the electric motor, an electric motor speed sensor that detects a rotation speed of the electric motor, and a power generation voltage of the motor is detected and calculated. A generated voltage calculator, an absolute value function unit for calculating the absolute value of the motor rotation speed detected by the motor speed sensor, and a magnetic flux command source signal divided by the absolute value of the motor rotation speed output from the absolute value function unit Means for calculating a magnetic flux command value, and a multiplier for multiplying the output of the divider by a value in which the upper limit of the generated voltage calculated by the generated voltage calculator is limited; A speed regulator to which a deviation between a constant value and a motor rotational speed detected by the motor speed sensor is input; an upper limiter for limiting an upper limit of a torque command value output from the speed regulator by a torque limit value; and the upper limit A divider that calculates a torque current command value by dividing a torque command value with a limited upper limit output from the limiter by the magnetic flux command value, and specifications of a device in which the motor is used with an absolute value of the motor rotation speed. A divider that divides the first rotational speed determined to satisfy, and the output of the divider is multiplied by a value that limits the upper limit of the generated voltage calculated by the generated voltage calculator, and the torque limit value is obtained. It means for calculating a composed torque current command value and the calculated multipliers, characterized in that a means for driving the power conversion device based on the magnetic flux command value and the torque current command value There.

  According to this configuration, the upper limit of the torque of the electric motor is inversely proportional to the speed of the electric motor and limited in proportion to the voltage of the generator, so that the generator can be prevented from being overloaded. Further, since the magnetic flux of the electric motor is inversely proportional to the rotational speed of the electric motor and is controlled in proportion to the voltage of the generator, it is possible to avoid the distortion of the electric motor voltage due to the voltage drop of the generator.

According to a third aspect of the present invention, there is provided an electric motor control apparatus comprising: a prime mover that is a power source; a generator that generates alternating current power according to the power of the prime mover; and the alternating current power of the generator is converted to direct current power. An electric motor control device having a power conversion device that converts the DC power into electric power for driving and controlling the electric motor, an electric motor speed sensor that detects the rotational speed of the electric motor, and a prime mover speed sensor that detects the rotational speed of the prime mover When the generated voltage calculator for calculating by detecting the generated voltage of the motor, the upper limit of the computed power generation voltage by the rotation speed and the generated voltage calculator of the prime mover detected by the engine speed sensor is limited value And a selector that selects a value having a small ratio to the rating, and an absolute value function unit that calculates the absolute value of the motor rotation speed detected by the motor speed sensor. A divider that divides the magnetic flux command source signal by the absolute value of the motor rotation speed output from the absolute value function unit, and the upper limit of the generated voltage calculated by the generated voltage calculator is limited to the output of the divider Means for calculating a magnetic flux command value composed of a multiplier for multiplying the value, a speed regulator for inputting a deviation between a speed setting value and the motor rotational speed detected by the motor speed sensor, and the speed regulator An upper limit limiter that limits the upper limit of the torque command value output from the torque limit value, and a torque command value that is limited from the upper limit output from the upper limiter is divided by the magnetic flux command value to calculate a torque current command value A divider that divides a first rotational speed determined to satisfy a specification of a device in which the electric motor is used by an absolute value of the electric motor rotational speed, and an output of the divider by the selector Selected Means for calculating a torque current command value comprising a multiplier for multiplying the calculated value to calculate the torque limit value, and means for driving the power converter based on the magnetic flux command value and the torque current command value It is characterized by having.

According to this configuration, among the value of either the value limit is restricted rotation speed and the generator voltage of the prime mover, the direction of the voltage of the generator to a small percentage of rated generator Since the upper limit of the torque of the motor is limited by the voltage, priority is given to the overload protection of the generator, and as a result, the overload of the prime mover is also protected. That is, the prime mover and the generator can be prevented from being overloaded.
According to a fourth aspect of the present invention, there is provided a motor control apparatus comprising: a prime mover that is a power source; a generator that generates AC power according to the power of the prime mover; and a rectifier that converts the AC power of the generator into DC power . When the rotational speed of the at motor control apparatus having an inverter for converting the power to a DC power by converting drives and controls the motor with a rectifier, a motor speed sensor for detecting a rotational speed of the motor, before Kihara motivation a prime mover speed sensor for detecting a voltage sensor for detecting an input voltage of the inverter, the motor speed upper limitation value of the sensor in the rotation speed of the prime mover detected input voltage of the inverter detected by the voltage sensor And a selector that selects a value that has a small ratio to the rating, and an absolute value of the motor rotation speed detected by the motor speed sensor. An absolute value function unit to calculate, a divider for dividing the magnetic flux command source signal by the absolute value of the motor rotation speed output from the absolute value function unit, and an output of the inverter detected by the voltage sensor at the output of the divider Means for calculating a magnetic flux command value composed of a multiplier for multiplying a value whose upper limit of the input voltage is limited, and a speed at which a deviation between the speed set value and the motor rotation speed detected by the motor speed sensor is input A controller, an upper limiter for limiting an upper limit of the torque command value output from the speed controller by a torque limit value, and a torque command value for which the upper limit is output from the upper limiter is divided by the magnetic flux command value. A divider that calculates a torque current command value, and a divider that divides the first rotational speed determined to satisfy the specifications of the device in which the electric motor is used by the absolute value of the electric motor rotational speed; Means for calculating a torque current command value constituted by a multiplier for calculating the torque limit value by multiplying an output of the divider by a value selected by the selector; the magnetic flux command value and the torque current command value And a means for driving the inverter based on the above.

According to this configuration, among the value of either the value limit is restricted rotation speed and the inverter input voltage of the prime mover, for example, towards the inverter input voltage is a percentage of the rated small, the inverter Since the upper limit of the torque of the motor is limited by the input voltage, priority is given to the overload protection of the generator, and as a result, the overload of the prime mover is also protected. That is, the prime mover and the generator can be prevented from being overloaded.

The electric motor control device according to claim 5 of the present invention, in claim 4, the output side of the selector, among the value limit is restricted input voltage of the rotational speed and the inverter of the prime mover, When the upper limit of the torque of the electric motor is limited with a smaller ratio with respect to each rating, if the value to be limited is reduced, the value is smoothly reduced with a large time constant, and the limitation is performed. A feature is that a time constant control unit is provided for rapidly changing the value with a small time constant when the value increases.

According to this arrangement, when any of the values of the upper limit is restricted rotation speed Do及 beauty inverter input voltage of the prime mover is reduced by smoothly reducing the value with a large time constant, the torque of the motor in this parameter Limit the upper limit of. Also, when the value with the upper limit restricted increases, the value is changed rapidly with a small time constant, and the upper limit of the torque of the motor is restricted with this value. That is, when lowering the torque limit value, the desired value can be output only for a predetermined time that can be allowed by the prime mover or the generator by taking a predetermined time limit and reducing the limit value. Or the continuous overload of a generator can be prevented.

  As described above, according to the present invention, in applications where the motor requires a large torque at a low speed, even when the rotational speed of the prime mover or the generator voltage drops below a predetermined value, the prime mover or the generator is overloaded. In addition, by making it possible to limit the upper limit of the output of the prime mover, it is possible to prevent a sudden stop of the motor in response to a sudden stall stop of the prime mover, thereby preventing troubles in the applicable equipment of the motor. There is an effect that it can be eliminated.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, parts corresponding to each other in all the drawings in this specification are denoted by the same reference numerals, and description of the overlapping parts will be omitted as appropriate.
(First embodiment)
FIG. 1 is a block diagram showing a configuration of an electric motor control device according to a first embodiment of the present invention.
In the present embodiment, a case where the rectifier 3 and the inverter 4 are used as a power converter, the induction motor 5 is used as an electric motor, and vector control is used for controlling the induction motor 5 will be described as an example. It is assumed that various control amounts are standardized with predetermined values, and various proportional coefficients are omitted.

AC power is generated by a generator 2 coupled to the prime mover 1, and this is rectified by a rectifier 3 and converted to DC power. An inverter 4 is connected to the rectifier 3, and the induction motor 5 is driven by the inverter 4.
This configuration is the same as that of the conventional example, but in the present embodiment, a current sensor 6 and a speed sensor 7 coupled to the rotor of the induction motor 5 are connected to the induction motor 5. The speed sensor 8 is coupled to the two rotors.

In the motor control device 100-1, ω * is a speed set value (second rotational speed), and the speed regulator 11 amplifies a deviation between the speed set value ω * and the speed ω detected by the speed sensor 7. To do. The output of the speed adjuster 11 corresponds to a torque command, and the upper limit of the value is limited to T _LIM * (torque limit value). The value limited by the upper limiter 12 is the torque command value T *. The torque current command value I _T * is calculated by dividing T * by the magnetic flux command value Ψ * of the induction motor 5 by the divider 13.

On the other hand, the original signal Ψ ** of the magnetic flux command value Ψ * is divided by the divider 14 by the absolute value ω _ABS of the speed ω, and the value obtained by this division is multiplied by the rotational speed ω _G of the prime mover 1 by the multiplier 15. The output is limited by the upper limiter 16 to obtain the magnetic flux command value Ψ *.
For the absolute value ω _ABS of the rotational speed ω of the induction motor 5, the absolute value function unit 18 obtains the absolute value of the rotational speed ω of the induction motor 5 from the speed sensor 7, and this value is limited by the lower limiter 19. Can be obtained. The lower limiter 19 is provided so as not to cause an overflow in the operations of the divider 14 and the divider 20.

In the divider 20, the rotation speed (first rotation speed) ω ₀ determined to satisfy the specifications of the equipment in which the induction motor 5 is used is divided by the absolute value ω _ABS of the speed to calculate T _LIM **. To do. By multiplying this T _LIM ** by the multiplier 21 by the rotational speed ω _G of the prime mover 1 from the speed sensor 8, the upper limit value of the value obtained thereby is limited by the upper limit limiter 22. _{Find LIM} *.

The calculation result of the torque limit value T _LIM * is shown in FIG. In the figure, the thin solid line is an example when the rotational speed ω _G of the prime mover 1 is the rated value (100%), and the thick solid line is an example when the rotational speed ω _G is 80% of the rated value. The short-time rated torque is 200%. When the rotational speed ω _G of the prime mover 1 is 100%, the speed (first rotational speed) ω ₀ becomes a speed 0.5 Nb that is 50% of the base speed Nb, and the torque limit value decreases from this speed. On the other hand, when the rotational speed ω _G of the prime mover 1 is reduced to 80%, the torque limit value is reduced from a speed 0.4 Nb that is 40% of the base speed Nb, thereby preventing overload of the prime mover 1.

The above is a part related to the present invention. In the other respects, the inverter 4 is controlled by the same vector control and PWM (pulse width modulation) control as in the prior art. This part will be briefly described.
When the torque current command value I _T * and the magnetic flux command value Ψ * are input to the vector calculator 23, the vector calculator 23 is based on the principle of vector control and the slip frequency of the induction motor 5 input from the current sensor 6. And the magnetizing current command value that contributes to the magnetic flux generation, and the actual values of the torque current and the magnetizing current are calculated from the phase current of the induction motor 5. Furthermore, current control is performed by feedback control via the pulse width controller 24 from these current command values and detected values.
These configurations are described in, for example, the publication of Nikkan Kogyo Shimbun published by Takayoshi Nakano, “Vector Control of AC Motors”. The output of the current regulator corresponds to the voltage command, and the inverter 4 is controlled by PWM control of this signal by the pulse width controller 24.

FIG. 3 is a diagram illustrating an example of a calculation result of the torque current command value I _T * obtained by the control of the electric motor control device 100-1.
In FIG. 3, as in FIG. 2, the thin solid line is an example when the rotational speed ω _G of the prime mover 1 is the rated value (100%), and the thick solid line is the case where the rotational speed ω _G is 80% of the rated value. It is an example. The short-time rated torque is 200%. Corresponding to the torque limit value in FIG. 2, when the rotational speed ω _G of the prime mover 1 is 100%, the torque current is reduced from 50% of the base speed Nb. When the rotational speed ω of the electric motor 5 is equal to or higher than the base speed Nb, the torque current is constant because the flux-weakening control is started from the same speed. When the rotational speed ω _G of the prime mover 1 decreases to 80%, the torque current decreases from a speed 0.4 Nb, which is 40% of the base speed Nb, and is constant when the rotational speed ω of the motor 5 is equal to or higher than 80% of the base speed Nb. Become. This is because the flux-weakening control is started from 80% of the base speed Nb. In this way, the desired control is achieved.

Thus, according to the electric motor control device 100-1 of the first embodiment, in an application where the electric motor 5 is required to have a short-time overload characteristic only at a base speed Nb or less, such as ice breaker electric propulsion, it is possible to restrict the upper limit of the flux and torque of the motor 5 in accordance with the rotational speed omega _G prime mover 1, even when the rotation speed omega _G and voltage of the generator 2 of the engine 1 becomes lower than a predetermined value, the prime mover 1 And the generator 2 can be prevented from being overloaded. Thereby, the prime mover 1 and the generator 2 can be reduced in size.

Furthermore, since the torque of the electric motor 5 is limited to the minimum necessary, the torque is not limited even if the rotational speed ω _{G of the} prime mover 1 decreases, for example, when the rotational speed of the electric motor 5 is equal to or lower than a predetermined speed. In addition, by providing a time limit characteristic for limiting the torque of the electric motor 5, a desired torque can be obtained in a short time, thereby preventing troubles in the operation of the electric motor 5.

(Second Embodiment)
FIG. 4 is a block diagram showing the configuration of the motor control device according to the second embodiment of the present invention.
The difference between the motor control device 100-2 of the second embodiment and the motor control device 100-1 of the first embodiment will be described.
In the motor control device 100-2, the voltage of the generator 2 is detected instead of the rotational speed ω _G of the prime mover 1. In order to do this, the generated voltage calculator 25 is connected between the voltage output side of the generator 2 and the multipliers 15, 21. However, an upper limiter 26 is provided after the generated voltage calculator 25. Then, the generated voltage calculator 25 calculates the magnitude V _G of the generated voltage from the voltage of the generator 2 and inputs this V _G to the multipliers 15 and 21 via the upper limiter 26. The upper limiter 26 performs an operation of limiting the voltage so that the upper limit of the torque is not changed even when the voltage of the generator 2 becomes 100% or more.

Thus, according to the electric motor control apparatus 100-2 of the second embodiment, in an application where the electric motor 5 is required to have a short-time overload characteristic only at a base speed Nb or less, such as ice breaker electric propulsion, Since the upper limit of the magnetic flux and torque of the electric motor 5 can be limited according to the voltage of the generator 2, even when the rotational speed ω _{G of} the prime mover 1 or the voltage of the generator 2 falls below a predetermined value, It is possible to prevent the machine 2 from being overloaded. Thereby, the prime mover 1 and the generator 2 can be reduced in size.
Further, since the torque of the electric motor 5 is limited to the minimum necessary, the torque is not limited even if the voltage of the generator 2 decreases, for example, when the rotational speed of the electric motor 5 is equal to or lower than a predetermined speed. In addition, by providing a time limit characteristic for limiting the torque of the electric motor 5, a desired torque can be obtained in a short time, thereby preventing troubles in the operation of the electric motor 5.

(Third embodiment)
FIG. 5 is a block diagram showing a configuration of an electric motor control device according to the third embodiment of the present invention.
The difference between the motor control device 100-3 of the third embodiment and the motor control device 100-2 of the second embodiment will be described.
In the motor control unit 100-3, in place of the power voltage V _G, and to detect the input voltage Ed of the inverter 4. In order to do this, the generated voltage calculator 25 is removed, the voltage sensor 9 is connected between the rectifier 3 and the inverter 4, and the input voltage Ed detected by the voltage sensor 9 is limited by the upper limiter 26. 15 and 21.

Thus, according to the electric motor control device 100-3 of the third embodiment, in an application in which the electric motor 5 is required to have a short-time overload characteristic only at a base speed Nb or less, such as ice breaker electric propulsion, Since the upper limit of the magnetic flux and torque of the electric motor 5 can be limited according to the input voltage Ed of the inverter 4, even when the rotational speed ω _{G of} the prime mover 1 or the voltage of the generator 2 falls below a predetermined value, the prime mover 1 or It is possible to prevent the generator 2 from being overloaded. Thereby, the prime mover 1 and the generator 2 can be reduced in size.

(Fourth embodiment)
FIG. 6 is a block diagram showing a configuration of an electric motor control device according to the fourth embodiment of the present invention.
The difference between the motor control device 100-4 of the fourth embodiment and the motor control device 100-1 of the first embodiment will be described.
In the motor control device 100-4, the generated voltage calculator 25 is connected between the voltage output side of the generator 2 and the multiplier 15, the ratio of the rotational speed ω _G of the prime mover 1 to the rating, among the ratio to the rated power voltage V _G from the voltage calculator 25, a selector 27 for selecting and outputting the parameters of the person ratio is small to divider 21, speed sensor 8, the power generation voltage calculator 25 and divide Connected between vessels 21. However, an upper limiter 26 is provided after the generated voltage calculator 25.

In such a configuration, for example, when the rotational speed ω _G of the prime mover 1 is 90% of the rating and the voltage of the generator 2 is 80% of the rating, the voltage V _{G of the} generator 2 is selected by the selector 27. To the multiplier 21. As a result, the overload protection of the generator 2 is prioritized, and as a result, the overload of the prime mover 1 can be protected.
As described above, according to the motor control device 100-4 of the fourth embodiment, the ratio of each parameter of the rotational speed ω _G of the prime mover 1 and the voltage V _G of the generator 2 to each rating. Since the upper limit of the torque of the electric motor 5 is limited by the smaller parameter, the overload protection of the generator 2 or the prime mover 1 has priority, and as a result, the other overload can be protected.

(Fifth embodiment)
FIG. 7 is a block diagram showing the configuration of the motor control device according to the fifth embodiment of the present invention.
The difference between the motor control device 100-5 of the fifth embodiment and the motor control device 100-4 of the fourth embodiment will be described.
In the motor control unit 100-4, in place of the power voltage V _G, and to supply the input voltage Ed of the inverter 4 to the selector 27. In order to do this, the generator voltage calculator 25 is removed, the voltage sensor 9 is connected between the rectifier 3 and the inverter 4, and the input voltage Ed detected by the voltage sensor 9 is limited by the upper limiter 26 while being selected. 27.

The selector 27 selects a parameter having a smaller ratio from the ratio of the rotational speed ω _G of the prime mover 1 to the rating and the ratio of the input voltage Ed of the inverter 4 to the divider 21 and outputs the selected parameter.
In such a configuration, for example, when the rotational speed ω _G of the prime mover 1 is 90% of the rating and the input voltage Ed of the inverter 4 is 80% of the rating, the selector 27 selects the input voltage Ed of the inverter 4. To the multiplier 21. As a result, the overload protection of the generator 2 is prioritized, and as a result, the overload of the prime mover 1 can be protected.

As described above, according to the motor control device 100-5 of the fifth embodiment, the ratio of each of the parameters of the rotational speed ω _G of the prime mover 1 and the input voltage Ed of the inverter 4 to each rating is as follows. Since the upper limit of the torque of the electric motor 5 is limited by the smaller parameter, the overload protection of the generator 2 or the prime mover 1 has priority, and as a result, the other overload can be protected.

(Sixth embodiment)
FIG. 8 is a block diagram showing the configuration of the motor control device according to the sixth embodiment of the present invention.
The motor control device 100-6 of the sixth embodiment is different from the motor control device 100-5 of the fifth embodiment in that a time constant control unit is provided between the selector 27 and the divider 21. 28 is connected.
As shown in FIG. 9, the time constant control unit 28 controls the output so that the output is smoothly reduced with a large time constant when the input is decreased, and the output is rapidly changed with a small time constant when the input is increased. As a result, for example, when the rotational speed ω _{G of the} prime mover 1 decreases from a predetermined value, the torque of the electric motor 5 does not rapidly decrease, but almost the desired torque is obtained for a while, and the torque is limited only in a steady state. The Further, if the rotational speed of the prime mover returns to a predetermined value, the torque limit is quickly released.

Thus, according to the electric motor control device 100-6 of the sixth embodiment, the parameter of either the rotational speed ω _G of the prime mover 1 selected by the selector 27 or the input voltage Ed of the inverter 4 is decreased. Sometimes the parameter is smoothly reduced with a large time constant, and the upper limit of the torque of the electric motor 5 is limited by this parameter. Further, when the parameter increases, the parameter is rapidly changed with a small time constant, and the upper limit of the torque of the electric motor 5 is limited by this parameter. That is, when lowering the torque limit value, the desired torque can be output only for a predetermined time that can be allowed by the prime mover 1 or the generator 2 by reducing the limit value by taking a predetermined time limit. And the continuous overload of the motor | power_engine 1 or the generator 2 can be prevented.

  In the above description, the case of vector control of the induction motor 5 has been described as each embodiment. However, it can be applied to vector control of a synchronous motor and control of a DC motor by adding a field circuit. it can. Moreover, a cycloconverter etc. other than the inverter 4 can be applied to the power converter.

It is a block diagram which shows the structure of the electric motor control apparatus which concerns on the 1st Embodiment of this invention. FIG. 5 is a relationship diagram between a rotation speed of an electric motor and a torque limit value. It is a relationship diagram between the rotational speed of a motor and a torque current command value. It is a block diagram which shows the structure of the electric motor control apparatus which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the electric motor control apparatus which concerns on the 3rd Embodiment of this invention. It is a block diagram which shows the structure of the electric motor control apparatus which concerns on the 4th Embodiment of this invention. It is a block diagram which shows the structure of the electric motor control apparatus which concerns on the 5th Embodiment of this invention. It is a block diagram which shows the structure of the electric motor control apparatus which concerns on the 6th Embodiment of this invention. It is a figure which shows the signal state of the output with respect to the input by which the time constant is controlled by the time constant control part of the electric motor control apparatus which concerns on 6th Embodiment. It is a relationship diagram of the rotational speed of the motor and the terminal voltage / magnetic flux when the motor is controlled at a variable speed. FIG. 6 is a relationship diagram between the rotational speed and torque of the motor when the motor is controlled at a variable speed. It is a related figure of the rotational speed of a motor, terminal voltage, and magnetic flux in the case of weakening the magnetic flux of an electric motor at the time of high speed, and reducing the terminal voltage of an electric motor. FIG. 6 is a relationship diagram between the rotational speed and torque of the motor when the magnetic flux of the motor is further weakened to reduce the terminal voltage of the motor at high speed. It is a block diagram which shows the structure of the variable speed apparatus of the motor in the case of making the conventional prime mover into a motive power source. It is a related figure of the rotational speed of a motor in the case of variable speed control of the conventional motor, and terminal voltage and magnetic flux. It is a related figure of the rotational speed and torque of a motor in the case of variable speed control of the conventional motor. It is a related figure of the rotational speed and torque at the time of short-time rating of the conventional electric motor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor | power_engine 2 Generator 3 Rectifier 4 Inverter 5 Induction motor 6 Current sensor 7, 8 Speed sensor 9 Voltage sensor 11 Speed regulator 12, 16, 22, 26 Upper limiter 13, 14, 20 Divider 15,21 Multiplier 18 Absolute 18 Value function unit 19 Lower limiter 24 Pulse width controller 25 Generated voltage calculator 27 Selector 28 Time constant control unit 100-1 to 100-6 Motor controller ω Speed of motor ω * Speed set value (second speed) )
T _LIM * torque limit value T * torque command value [psi * flux command value I _T * torque current value [psi ** flux command value [psi * of the original signal omega _ABS rotational speed of the absolute value omega _G prime mover of the motor speed of the omega ₀ Rotational speed (first rotational speed)
T _LIM ** Value of ω ₀ divided by ω _ABS Nb Base speed V _G Power generation voltage Ed Inverter input voltage

Claims (5)

A prime mover that is a power source, a generator that generates alternating current power according to the power of the prime mover, and the alternating current power of this generator is converted into direct current power, and this direct current power is converted into electric power for drive control of the motor In the electric motor control device having the power conversion device to
An electric motor speed sensor for detecting the rotational speed of the electric motor;
A prime mover speed sensor for detecting a rotational speed of the prime mover;
An absolute value function unit for calculating the absolute value of the motor rotation speed detected by the motor speed sensor, a divider for dividing the magnetic flux command source signal by the absolute value of the motor rotation speed output from the absolute value function unit, It means for calculating a composed magnetic flux command value in a multiplier for multiplying the rotation speed of the prime mover detected by the engine speed sensor to the output of the divider,
A speed regulator to which a deviation between the speed setting value and the motor rotation speed detected by the motor speed sensor is input; an upper limiter for limiting an upper limit of a torque command value output from the speed regulator by a torque limit value; A divider for calculating a torque current command value by dividing a torque command value output from the upper limiter with an upper limit limited by the magnetic flux command value; and a device in which the motor is used with an absolute value of the motor rotation speed. a divider for dividing the first rotational speed that is determined to meet the specifications, by multiplying the rotation speed of the detected prime mover by said prime mover speed sensor to the output of該除adder calculates the torque limit value Means for calculating a torque current command value comprising a multiplier for
An electric motor control device comprising: means for driving the power converter based on the magnetic flux command value and the torque current command value. A prime mover that is a power source, a generator that generates alternating current power according to the power of the prime mover, and the alternating current power of this generator is converted into direct current power, and this direct current power is converted into electric power for drive control In the electric motor control device having the power conversion device to
An electric motor speed sensor for detecting the rotational speed of the electric motor;
A generated voltage calculator for detecting and calculating the generated voltage of the prime mover;
An absolute value function unit for calculating the absolute value of the motor rotation speed detected by the motor speed sensor, a divider for dividing the magnetic flux command source signal by the absolute value of the motor rotation speed output from the absolute value function unit, Means for calculating a magnetic flux command value composed of a multiplier that multiplies the output of the divider by a value that limits the upper limit of the generated voltage calculated by the generated voltage calculator;
A speed regulator to which a deviation between the speed setting value and the motor rotation speed detected by the motor speed sensor is input; an upper limiter for limiting an upper limit of a torque command value output from the speed regulator by a torque limit value; A divider for calculating a torque current command value by dividing a torque command value output from the upper limiter with an upper limit limited by the magnetic flux command value; and a device in which the motor is used with an absolute value of the motor rotation speed. A divider that divides a first rotational speed determined to satisfy the specification, and the torque limit obtained by multiplying the output of the divider by a value that limits the upper limit of the generated voltage calculated by the generated voltage calculator. Means for calculating a torque current command value composed of a multiplier for calculating a value;
An electric motor control device comprising: means for driving the power converter based on the magnetic flux command value and the torque current command value . A prime mover that is a power source, a generator that generates alternating current power according to the power of the prime mover, and the alternating current power of this generator is converted into direct current power, and this direct current power is converted into electric power for drive control of the motor In the electric motor control device having the power conversion device to
An electric motor speed sensor for detecting the rotational speed of the electric motor;
A prime mover speed sensor for detecting a rotational speed of the prime mover;
A generated voltage calculator for detecting and calculating the generated voltage of the prime mover;
Wherein a value upper limit is limited to the calculated power generation voltage motor speed sensor rotation speed of the prime mover detected by the by the generated voltage calculator is input selector for selecting a value ratio is less to the rated among the respective When,
An absolute value function unit for calculating the absolute value of the motor rotation speed detected by the motor speed sensor, a divider for dividing the magnetic flux command source signal by the absolute value of the motor rotation speed output from the absolute value function unit, Means for calculating a magnetic flux command value composed of a multiplier that multiplies the output of the divider by a value that limits the upper limit of the generated voltage calculated by the generated voltage calculator;
A speed regulator to which a deviation between the speed setting value and the motor rotation speed detected by the motor speed sensor is input; an upper limiter for limiting an upper limit of a torque command value output from the speed regulator by a torque limit value; A divider for calculating a torque current command value by dividing a torque command value output from the upper limiter with an upper limit limited by the magnetic flux command value; and a device in which the motor is used with an absolute value of the motor rotation speed. A divider that divides the first rotational speed determined to satisfy the specification, and a multiplier that calculates the torque limit value by multiplying the output of the divider by a value selected by the selector. Means for calculating a torque current command value,
An electric motor control device comprising: means for driving the power converter based on the magnetic flux command value and the torque current command value. A prime mover that is a power source, a generator that generates AC power according to the power of the prime mover, a rectifier that converts the AC power of the generator into DC power, and the motor that drives the DC power converted by the rectifier. In an electric motor control device having an inverter that converts electric power to
An electric motor speed sensor for detecting the rotational speed of the electric motor;
A prime mover speed sensor for detecting a rotational speed of the front Kihara motivation,
A voltage sensor for detecting an input voltage of the inverter;
The prime mover speed sensor and the rotational speed of the prime mover detected value of the upper limit is restricted for the input voltage of the inverter detected by the voltage sensor is inputted, a selector for selecting values ratio is small relative to the rated among the respective ,
An absolute value function unit for calculating the absolute value of the motor rotation speed detected by the motor speed sensor, a divider for dividing the magnetic flux command source signal by the absolute value of the motor rotation speed output from the absolute value function unit, Means for calculating a magnetic flux command value constituted by a multiplier that multiplies the output of the divider by a value in which the upper limit of the input voltage of the inverter detected by the voltage sensor is limited;
A speed regulator to which a deviation between the speed setting value and the motor rotation speed detected by the motor speed sensor is input; an upper limiter for limiting an upper limit of a torque command value output from the speed regulator by a torque limit value; A divider for calculating a torque current command value by dividing a torque command value output from the upper limiter with an upper limit limited by the magnetic flux command value; and a device in which the motor is used with an absolute value of the motor rotation speed. A divider that divides the first rotational speed determined to satisfy the specification, and a multiplier that calculates the torque limit value by multiplying the output of the divider by a value selected by the selector. Means for calculating a torque current command value,
An electric motor control device comprising: means for driving the inverter based on the magnetic flux command value and the torque current command value. The output side of the selector, among the value limit is restricted rotation speed and the input voltage of the inverter of the motor, the value of the direction ratio is small for each of the rating, the upper limit of torque of the electric motor When limiting, when the value to be limited is reduced, the value is smoothly reduced with a large time constant, and when the value to be limited is increased, the time constant is abruptly changed with a small time constant. The motor control device according to claim 4, further comprising a control unit.

Images