JP5996031B1 - Control device for rotating electrical machine - Google Patents

Abstract

Even when alternator power generation control is performed by a synchronous rectification method, a control device for a rotating electrical machine capable of continuously switching the power generation control method while reducing a shock at the time of power generation control switching is obtained. When switching a power generation control method to an alternator power generation control, a first inverter power generation control by an asynchronous PWM signal generation unit (251), a second inverter power generation control by a synchronous PWM signal generation unit (252), and a synchronous rectification power generation. The control unit (253) is configured to sequentially switch to alternator power generation control. [Selection] Figure 1

Description

  The present invention relates to a control device for a rotating electrical machine that performs switching control of a plurality of power generation methods in accordance with the rotational speed when a rotating electrical machine having a winding set is driven as a generator.

  Conventionally, as a control method for a rotating electrical machine driven as a generator, an alternator power generation control that generates power by an electromotive force generated by the rotation of the rotating electrical machine, and an armature current that is phase-controlled from the inverter to the rotating electrical machine Inverter power generation control is known in which power generation is performed by boosting chopper control.

  Here, in the alternator power generation control, power cannot be generated unless the electromotive force of the rotating electrical machine is higher than the DC voltage applied to the inverter. Therefore, power cannot be generated unless the rotational speed of the rotating electrical machine is increased. On the other hand, in the inverter power generation control, since the electromotive force is boosted by the chopper control by flowing a phase-controlled armature current from the inverter to the motor, it is possible to generate power even when the rotational speed of the rotating electrical machine is low. Therefore, a technique for performing power generation control of a rotating electrical machine by combining both power generation control methods has been proposed (see, for example, Patent Document 1).

  Specifically, in the prior art described in Patent Document 1, when the rotational speed of the rotating electrical machine reaches a specific switching rotational speed, power generation control switching from inverter power generation control to alternator power generation control is performed. Moreover, in order to reduce the shock which arises at the time of such power generation control switching, a hysteresis is provided in the switching rotational speed.

Japanese Patent Laid-Open No. 2004-15847

  However, in the prior art described in Patent Document 1, the period of the switching control of the switching element of the inverter is not taken into consideration before and after the power generation control switching from the inverter power generation control to the alternator power generation control. Therefore, when alternator power generation control is performed by the synchronous rectification method, there is a problem that a shock occurs when power generation control is switched.

  The present invention has been made to solve the above-described problems. Even when alternator power generation control is performed by the synchronous rectification method, the power generation is continuously performed while reducing the shock at the time of power generation control switching. It is an object of the present invention to obtain a control device for a rotating electrical machine that can switch a control method.

  The rotating electrical machine control device according to the present invention is a rotating electrical machine control device that performs switching control of a plurality of power generation methods in accordance with the rotational speed of the rotating electrical machine when the rotating electrical machine having a winding set is driven as a generator. In addition, a switching element section in which a plurality of circuits having switching elements on each of the high potential side and the low potential side is connected in parallel, and a phase voltage command to each phase of the winding set is generated according to a control command to the rotating electrical machine A voltage command generation unit that outputs the generated phase voltage command, a switching signal generation unit that generates a switching control signal and performs switching control of each switching element of the switching element unit on and off according to the generated switching control signal, A switching signal comprising a current sensor for detecting a phase current flowing in each phase of the winding set and a rotation sensor for detecting the number of rotations. The generating unit generates an asynchronous carrier wave so that the carrier frequency becomes the set carrier frequency, and performs an amplitude comparison between the phase voltage command input from the voltage command generating unit and the generated asynchronous carrier wave. Asynchronous PWM signal generation unit that performs first inverter power generation control that generates a switching control signal, and a phase difference between a phase voltage command and a synchronous carrier wave is constant, and a pulse for one cycle of the electrical angle of the phase voltage command The synchronous PWM signal is generated as a switching control signal by generating a synchronous carrier wave while sequentially changing the number from the initial setting pulse number to 1 pulse in a decreasing direction and comparing the phase voltage command with the generated synchronous carrier wave. A synchronous PWM signal generator for performing the second inverter power generation control to be generated, and a phase current detected by the current sensor A synchronous rectification power generation control unit that performs alternator power generation control that generates a synchronous rectification signal as a switching control signal in accordance with the positive and negative of the first and second rotation speeds detected by the rotation sensor is smaller than the first set rotation speed, Inverter power generation control is performed, and when the rotational speed reaches the first set rotational speed, the second inverter power generation control is performed by switching from the first inverter power generation control to the second inverter power generation control. When the second set rotational speed is reached, the alternator power generation control is further switched from the second inverter power generation control to the alternator power generation control.

  According to the present invention, when the power generation control method is switched to the alternator power generation control, the second inverter power generation control by the synchronous PWM signal generation unit is switched to the alternator power generation control by the synchronous rectification power generation control unit. As a result, even when alternator power generation control is performed by a synchronous rectification method, a control device for a rotating electrical machine that can continuously switch power generation control methods while reducing shock at the time of power generation control switching is obtained. Can do.

It is a block diagram which shows the rotary electric machine control system in Embodiment 1 of this invention. FIG. 2 is an explanatory diagram for explaining an operation of an asynchronous PWM signal generation unit in FIG. 1. FIG. 2 is an explanatory diagram for explaining an operation of a synchronous PWM signal generation unit in FIG. 1. FIG. 2 is an explanatory diagram for explaining an operation of a synchronous PWM signal generation unit in FIG. 1. FIG. 2 is an explanatory diagram for explaining an operation of a synchronous PWM signal generation unit in FIG. 1. It is explanatory drawing for demonstrating operation | movement of the synchronous rectification electric power generation control part of FIG. It is explanatory drawing for demonstrating the switching operation | movement of the electric power generation control system by the switching signal generation part of FIG. It is explanatory drawing for demonstrating the method of setting the 2nd setting rotation speed in Embodiment 2 of this invention.

  Hereinafter, a control device for a rotating electrical machine according to the present invention will be described with reference to the drawings according to a preferred embodiment. In the description of the drawings, the same portions or corresponding portions are denoted by the same reference numerals, and redundant description is omitted.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram showing a rotating electrical machine control system according to Embodiment 1 of the present invention. In FIG. 1, the rotating electrical machine control system includes a rotating electrical machine 1 and a rotating electrical machine control device 2. Hereinafter, the control device 2 of the rotating electrical machine is simply referred to as the control device 2.

  The rotating electrical machine 1 functions as an electric motor and a generator, and is driven as an electric motor or a generator according to the control of the control device 2. The rotating electrical machine 1 includes a winding set 11 and a rotation sensor 12.

  The winding set 11 has each phase winding composed of a U-phase winding, a V-phase winding, and a W-phase winding. In FIG. 1, one winding group 11 is illustrated, but the number of winding groups 11 of the rotating electrical machine 1 is not particularly limited, and the type of connection of the winding group 11 is not particularly limited. It may be of any kind. Moreover, in this Embodiment 1, although the case where this invention is applied to a synchronous motor with a magnet is illustrated, it is also applied to a synchronous motor with a field winding that generates a magnetomotive force by energizing a field coil without using a magnet. The present invention can be applied.

  The rotation sensor 12 detects the rotor position corresponding to the rotation phase of the rotating electrical machine 1 and the rotational speed of the rotating electrical machine 1, and outputs the detected rotor position and rotational speed to the control device 2. In the following, the rotational speed of the rotating electrical machine 1 is simply abbreviated as the rotational speed. As the rotation sensor 12, a conventional sensor can be used, and the type of sensor is not particularly limited.

  The control device 2 performs overall control of the rotating electrical machine control system, and is configured using, for example, a microcomputer.

  The control device 2 includes a switching element unit 21, a current sensor 22, a current command generation unit 23, a voltage command generation unit 24, and a switching signal generation unit 25.

  The DC power supply 3 outputs a DC voltage to the switching element unit 21. For example, a battery can be used as the DC power source 3.

  The smoothing capacitor 4 is provided in a state of being connected in parallel to the DC power source 3 in order to suppress fluctuations in the bus current and realize a stable DC current.

  In the switching element unit 21, three half-bridge circuits having semiconductor switching elements on the high potential side and the low potential side are connected in parallel. Specifically, the switching element unit 21 includes a high potential side switching element composed of switching elements Sup, Svp and Swp and a low potential side switching element composed of switching elements Sun, Svn and Swn.

  A connection point connecting the pair of switching elements Sup and Sun is connected to one end of the U-phase winding. A connection point connecting the pair of switching elements Svp and Svn is connected to one end of the V-phase winding. Furthermore, the connection point of the pair of switching elements Swp and Swn is connected to one end of the W-phase winding.

  Each switching element of the switching element unit 21 is controlled to be turned on and off in accordance with a switching control signal input from a switching signal generation unit 25 described later. Thus, by controlling the switching of each switching element of the switching element unit 21, the rotating electrical machine 1 can be controlled.

  The current sensor 22 detects a current that is passed through each phase of the rotating electrical machine 1. Specifically, the current sensor 22 detects a U-phase current as a current flowing through the U-phase winding, detects a V-phase current as a current flowing through the V-phase current, and a W-phase current as current flowing through the W-phase winding. Is detected. Further, the current sensor 22 outputs the detected phase currents to the voltage command generation unit 24 and the switching signal generation unit 25.

  The current command generator 23 converts a torque command input as a control command to the rotating electrical machine 1 into a current command, and outputs the converted current command to the voltage command generator 24. Note that a current command may be directly input to the voltage command generation unit 24 as a control command to the rotating electrical machine 1.

  The voltage command generator 24 outputs each phase voltage command according to the rotor position input from the rotation sensor 12, each phase current input from the current sensor 22, and the current command input from the current command generator 23. Generate. Specifically, the voltage command generation unit 24 controls each phase by proportional-integral control so that the deviation between the current command input from the current command generation unit 23 and each phase current input from the current sensor 22 becomes zero. Calculate the voltage command. As described above, the voltage command generator 24 calculates each phase voltage command by current feedback control.

  The switching signal generation unit 25 generates a switching control signal for performing switching control of each switching element of the switching element unit 21 on and off in accordance with each phase voltage command input from the voltage command generation unit 24. The switching signal generation unit 25 includes an asynchronous PWM signal generation unit 251, a synchronous PWM signal generation unit 252, and a synchronous rectification power generation control unit 253.

  The asynchronous PWM signal generation unit 251 operates when the rotating electrical machine 1 is driven as an electric motor or driven as a generator, and performs asynchronous PWM control. Further, when performing asynchronous PWM control, the asynchronous PWM signal generation unit 251 generates an asynchronous PWM signal as a switching control signal in accordance with each phase voltage command input from the voltage command generation unit 24, and switches the generated switching control signal. Output to the element unit 21.

  The synchronous PWM signal generation unit 252 operates when the rotating electrical machine 1 is driven as an electric motor or driven as a generator, and performs synchronous PWM control. Further, when performing synchronous PWM control, the synchronous PWM signal generator 252 generates a synchronous PWM signal as a switching control signal in accordance with each phase voltage command input from the voltage command generator 24, and switches the generated switching control signal Output to the element unit 21.

  Here, when the rotating electrical machine 1 is driven as a generator, the electromotive force of the rotating electrical machine 1 is small in a region where the rotational speed is low, so that sufficient generated power is supplied to the DC power source 3 only by rectifying the electromotive force. I can't. Therefore, each of the asynchronous PWM signal generation unit 251 and the synchronous PWM signal generation unit 252 performs switching control of each switching element of the switching element unit 21 on and off as inverter power generation control, thereby generating the electromotive force of the rotating electrical machine 1. After boosting the voltage, the generated power is supplied to the DC power source 3.

  Hereinafter, the inverter power generation control performed by the asynchronous PWM signal generation unit 251 is referred to as first inverter power generation control, and the inverter power generation control performed by the synchronous PWM signal generation unit 252 is referred to as second inverter power generation control.

  Asynchronous PWM signal generation unit 251 generates an asynchronous PWM signal as a switching control signal in accordance with each phase voltage command input from voltage command generation unit 24 as the first inverter power generation control. The synchronous PWM signal generation unit 252 generates a synchronous PWM signal as a switching control signal in accordance with each phase voltage command input from the voltage command generation unit 24 as the second inverter power generation control.

  The synchronous rectification power generation control unit 253 operates when the rotating electrical machine 1 is driven as a generator, and performs alternator power generation control.

  Here, when the rotating electrical machine 1 is driven as a generator, the electromotive force of the rotating electrical machine 1 is large in a region where the rotational speed is high, and therefore it is not necessary to boost the electromotive force. Therefore, the synchronous rectification power generation control unit 253 supplies the generated power to the DC power supply 3 by rectifying the electromotive force of the rotating electrical machine 1 by the synchronous rectification method as the alternator power generation control.

  As an alternator power generation control, the synchronous rectification power generation control unit 253 generates a synchronous rectification signal as a switching control signal according to the positive / negative of each phase current input from the current sensor 22.

  When driving the rotating electrical machine 1 as a generator, the switching signal generating unit 25 controls the rotating electrical machine 1 by outputting a switching control signal to the switching element unit 21 while switching the power generation control method.

  That is, when driving the rotating electrical machine 1 as a generator, first, the first inverter power generation control by the asynchronous PWM signal generation unit 251 is performed. Subsequently, the second inverter power generation control is performed by switching to the second inverter power generation control by the synchronous PWM signal generation unit 252. Furthermore, the alternator power generation control is performed by switching to the alternator power generation control by the synchronous rectification power generation control unit 253. Such switching of the power generation control method is performed according to the rotation speed input from the rotation sensor 12.

  Next, control performed by each of the asynchronous PWM signal generation unit 251 and the synchronous PWM signal generation unit 252 when the rotating electrical machine 1 is driven as an electric motor or a generator will be described with reference to FIGS.

  FIG. 2 is an explanatory diagram for explaining the operation of the asynchronous PWM signal generation unit 251 of FIG. 3, 4, and 5 are explanatory diagrams for explaining the operation of the synchronous PWM signal generation unit 252 of FIG. 1.

  As shown in FIG. 2, the asynchronous PWM signal generation unit 251 performs amplitude comparison between the phase voltage command input from the voltage command generation unit 24 and the generated carrier wave.

  Asynchronous PWM signal generation unit 251 asynchronously outputs a switching control signal for switching on and off each switching element of switching element unit 21 according to the comparison result, that is, the amplitude relationship between the phase voltage command and the carrier wave. A PWM signal is generated.

  As shown in FIGS. 3 to 5, the synchronous PWM signal generation unit 252 also compares the amplitude of the phase voltage command input from the voltage command generation unit 24 and the generated carrier wave, similarly to the asynchronous PWM signal generation unit 251. To generate a synchronous PWM signal as a switching control signal.

  Hereinafter, the carrier wave generated by the asynchronous PWM signal generation unit 251 is referred to as an asynchronous carrier wave, and the carrier wave generated by the synchronous PWM signal generation unit 252 is referred to as a synchronous carrier wave.

  Next, generation of an asynchronous carrier wave by the asynchronous PWM signal generation unit 251 and generation of a synchronous carrier wave by the synchronous PWM signal generation unit 252 will be described.

  The asynchronous PWM signal generation unit 251 generates a triangular wave having a preset carrier frequency as an asynchronous carrier wave. The phase difference between the phase voltage command input from the voltage command generation unit 24 and the asynchronous carrier wave generated by the asynchronous PWM signal generation unit 251 is an arbitrary value.

  On the other hand, the synchronous PWM signal generation unit 252 generates a synchronous carrier wave having a constant phase difference from the phase voltage command input from the voltage command generation unit 24 while changing the carrier frequency in accordance with the electrical angular frequency.

  Here, the synchronous PWM signal generation unit 252 changes the carrier frequency of the synchronous carrier wave so that the phase difference between the phase voltage command and the PWM carrier wave is constant. When the phase difference between the phase voltage command and the synchronous carrier wave is constant, the relationship of the following formula (1) is established between the carrier frequency of the synchronous carrier wave and the electrical angular frequency of the phase voltage command. . However, N is an integer greater than or equal to 0.

    Carrier frequency = 3 × N × electrical angular frequency (1)

  That is, the synchronous PWM signal generation unit 252 generates a synchronous carrier wave while changing the carrier frequency so as to satisfy Expression (1). Specifically, as shown in FIG. 3, if a 15-pulse synchronous carrier wave is generated, the carrier frequency becomes 15 times the electrical angular frequency. Further, as shown in FIG. 4, if a three-pulse synchronous carrier wave is generated, the carrier frequency becomes three times the electrical angular frequency. Further, as shown in FIG. 5, if a single pulse synchronous carrier wave is generated, the carrier frequency and the electrical angular frequency coincide.

  Further, when considering a switching element that is switching-controlled according to the switching control signal generated by the synchronous PWM signal generation unit 252, switching occurs at the intersection of the synchronous carrier wave and the phase voltage command. Therefore, as can be seen from FIGS. 3 to 5, the number of times of switching decreases as the number of pulses of the synchronous carrier wave decreases. Further, as shown in FIG. 5, when the number of pulses is one, the switching element is switched on and off only twice for one electrical angle cycle.

  Next, the operation of the synchronous rectification power generation control unit 253 will be described with reference to FIG. FIG. 6 is an explanatory diagram for explaining the operation of the synchronous rectification power generation control unit 253 of FIG. The synchronous rectification power generation control unit 253 generates a synchronous rectification signal as a switching control signal according to the positive / negative of each phase current input from the current sensor 22 in order to perform the alternator power generation control by the synchronous rectification method.

  Here, the synchronous rectification method is such that the switching element is switched on and off in accordance with the direction of the current flowing in each phase of the rotating electrical machine 1, so that the resistance is smaller than the on-resistance of the parasitic diode instead of the parasitic diode. In this method, a current flows through the switching element. By performing power generation control by such a synchronous rectification method, power generation efficiency can be increased, and loss of generated power generated in the switching element unit 21 can be reduced.

  Specifically, the synchronous rectification power generation control unit 253 performs power generation control so that switching occurs when the phase of the phase current input from the current sensor 22 is 0 deg and 180 ded, as shown in FIG. . That is, the synchronous rectification power generation control unit 253 generates a synchronous rectification signal as a switching control signal according to the sign of each phase current input from the current sensor 22.

  Here, as can be seen from FIGS. 5 and 6, in the alternator power generation control, switching control is performed in the same cycle as when one pulse of the synchronous carrier wave is used in the second inverter power generation control.

  Therefore, when switching the power generation control method from the inverter power generation control to the alternator power generation control, by switching from the second inverter power generation control to the alternator power generation control, switching control of the same cycle before and after the switching can be realized. it can. Therefore, it is possible to continuously switch the power generation control method while reducing the shock at the time of switching compared to the conventional case.

  Next, the switching operation of the power generation control method by the switching signal generation unit 25 will be further described with reference to FIG. FIG. 7 is an explanatory diagram for explaining the switching operation of the power generation control method by the switching signal generation unit 25 of FIG. Note that FIG. 7 illustrates a case where the torque command is a constant negative value, that is, −T, and the rotational speed increases with time. In FIG. 7, at time T2 when the rotation speed reaches the first set rotation speed N1, the first inverter power generation control is switched to the second inverter power generation control, and at time T3 when the rotation speed reaches the second set rotation speed N2. The case where it is set to switch from the second inverter power generation control to the alternator power generation control is illustrated. The first set speed N1 and the second set speed N2 that is larger than the first set speed N1 are set in advance.

  In the period from time T1 to T2, since the rotation speed is in a region lower than the first set rotation speed N1, the first inverter power generation control by the asynchronous PWM signal generation unit 251 is performed. The first set rotational speed N1 may be set in advance in consideration of the advantages of applying the synchronous PWM method described below.

  Here, in a region where the rotational speed is low, one electrical angle cycle of the phase voltage command is very long compared to the carrier cycle of the carrier wave. Therefore, when the synchronous PWM method is applied, the number of pulses is greatly increased, so that the switching operation of the switching element is similar to that when the asynchronous PWM method is applied. Therefore, it can be said that there is no advantage in applying the synchronous PWM method when the rotation speed is low.

  Therefore, when the rotational speed is low, the asynchronous PWM signal generation unit 251 performs the first inverter power generation control, so that the asynchronous PWM signal is output to the switching element unit 21 as a switching control signal.

  Subsequently, as the number of rotations increases, one electrical angle cycle of the phase voltage command is shortened, so that it is not necessary to greatly increase the number of pulses when applying the synchronous PWM method. Therefore, at time T2 when the rotational speed reaches the first set rotational speed N1, the first inverter power generation control by the asynchronous PWM signal generation unit 251 is switched to the second inverter power generation control by the synchronous PWM signal generation unit 252. Further, in the period from time T2 to T3, the second inverter power generation control by the synchronous PWM signal generation unit 252 is performed.

  Here, when switching from the first inverter power generation control to the second inverter power generation control, when switching to the second inverter power generation control in a state where the number of pulses of the synchronous carrier wave is small, the carrier frequency before and after the switching changes suddenly and the current pulsation increases. turn into. In order to suppress such current pulsation, the number of pulses of the synchronous carrier wave when switching to the second inverter power generation control is set to be large.

  Further, when switching from the second inverter power generation control to the alternator power generation control, as described above, in order to realize the switching control of the same period before and after switching, the number of pulses of the synchronous carrier wave is set to 1 pulse. .

  Therefore, the number of pulses of the synchronous carrier wave generated by the synchronous PWM signal generation unit 252 is 15 pulses when the rotational speed reaches the first set rotational speed N1, and from 15 pulses to 9 pulses, 3 pulses according to the rotational speed. And the change pattern is set so as to be 1 pulse when the rotational speed reaches the second set rotational speed N2.

  Here, the case where the initial setting pulse number is set to 15 pulses is exemplified as the pulse number of the synchronous carrier wave when the rotation speed reaches the first setting rotation speed N1, but the initial setting pulse number is exemplified. The numerical value is merely an example, and the numerical value can be changed as appropriate. In addition, a change pattern is illustrated in which the number of pulses of the synchronous carrier wave is sequentially changed from 15 pulses to 9 pulses and 3 pulses according to the number of rotations until the number of pulses of the synchronous carrier wave becomes one pulse. The change pattern is only an example. That is, the change pattern can be appropriately changed as long as the change pattern is such that the number of pulses of the synchronous carrier wave becomes 1 pulse when the rotation speed reaches the second set rotation speed N2.

  Subsequently, as the rotational speed is further increased, the electromotive force of the rotating electrical machine 1 is increased. Therefore, at time T3 when the rotation speed reaches the second set rotation speed N2, the second inverter power generation control by the synchronous PWM signal generation unit 252 is switched to the alternator power generation control by the synchronous rectification power generation control unit 253. Further, after time T3, alternator power generation control by the synchronous rectification power generation control unit 253 is performed.

  As described above, when the rotating electrical machine 1 is driven as a generator, the first inverter power generation control, the second inverter power generation control, and the alternator power generation control are sequentially switched according to the rotational speed of the rotating electrical machine 1.

  In the first embodiment, when the rotation speed reaches the first set rotation speed N1, switching from the first inverter power generation control to the second inverter power generation control is performed, and the rotation speed is changed to the second set rotation speed N2. The case where the switching from the second inverter power generation control to the alternator power generation control is performed if it arrives is illustrated. However, hysteresis may be provided in at least one of the first set speed N1 and the second set speed N2. Thereby, it is possible to suppress frequent switching in the vicinity of the set rotational speed at which hysteresis is provided, and as a result, it is possible to realize suppression of shock due to switching.

  In the first embodiment, the number of pulses of the synchronous carrier wave generated by the synchronous PWM signal generation unit 252 is exemplified in accordance with the number of rotations. However, according to the current command generated by the current command generation unit 23 You may make it change sequentially. In this case, the current command generated by the current command generator 23 is input to the synchronous PWM signal generator 252. Further, the number of pulses of the synchronous carrier wave generated by the synchronous PWM signal generation unit 252 may be sequentially changed according to the torque command input to the current command generation unit 23. In this case, a torque command is input to the synchronous PWM signal generation unit 252.

  In the first embodiment, the case where the switching from the second inverter power generation control to the alternator power generation control is performed when the rotation speed reaches the second set rotation speed N2 is illustrated. However, switching from the second inverter power generation control to the alternator power generation control is performed at a timing when the rotation speed reaches the second set rotation speed N2 and the phase voltage command generated by the voltage command generation unit 24 becomes zero. You may do it. Thereby, it becomes possible to further reduce the shock caused by switching.

  As described above, according to the first embodiment, the asynchronous carrier wave is generated so that the carrier frequency becomes the set carrier frequency, and the amplitude comparison between the phase voltage command input from the voltage command generation unit and the generated asynchronous carrier wave is performed. Asynchronous PWM signal generation unit that performs first inverter power generation control that generates an asynchronous PWM signal as a switching control signal, and the phase difference between the phase voltage command and the synchronous carrier wave is constant, and the electrical angle of the phase voltage command Synchronized by generating a synchronized carrier wave while sequentially changing the number of pulses per cycle from the initial number of pulses to 1 pulse in a decreasing direction, and comparing the amplitude of the phase voltage command with the generated synchronized carrier wave A synchronous PWM signal generator for performing second inverter power generation control for generating a PWM signal as a switching control signal, and a current sensor A synchronous rectification power generation control unit for an alternator power generation control that generates a switching control signal synchronous rectification signal according polarity of the detected phase current I is configured to have a.

  In addition, when the rotation speed detected by the rotation sensor is smaller than the first set rotation speed, the first inverter power generation control is performed, and when the rotation speed reaches the first set rotation speed, the first inverter power generation control When switched to 2-inverter power generation control, second inverter power generation control is performed, and when the rotational speed reaches a second set rotational speed greater than the first set rotational speed, the second inverter power generation control is further switched to alternator power generation control. Then, alternator power generation control is performed.

  As a result, even when alternator power generation control is performed by the synchronous rectification method, it is possible to continuously switch the power generation control method while reducing a shock at the time of power generation control switching.

Embodiment 2. FIG.
In the second embodiment of the present invention, a more optimal setting method of the second set rotational speed N2 for switching from the second inverter power generation control to the alternator power generation control will be described with reference to FIG. FIG. 8 is an explanatory diagram for explaining a method of setting the second set rotational speed N2 in the second embodiment of the present invention. In the second embodiment, the description of the same points as in the first embodiment will be omitted, and the description will focus on the points different from the first embodiment.

  In FIG. 8, the change characteristic of the power generation torque that can be generated by the alternator power generation control with respect to the rotation speed of the rotating electrical machine 1 and the power generation torque that can be generated by the second inverter power generation control with respect to the rotation speed of 1 of the rotating electrical machine. The change characteristics are also illustrated. Since the power generation torque characteristic shown in FIG. 8 is known in advance according to the type of the rotating electrical machine 1, the second set rotational speed N2 is set with reference to such a power generation torque characteristic.

  As shown in FIG. 8, regarding the power generation torque that can be generated by the alternator power generation control, power generation is not possible unless the electromotive force of the rotating electrical machine 1 is higher than the DC voltage applied to the switching element unit 21, so that the rotational speed is In the low region, the power generation torque is 0 Nm. In addition, when the rotational speed increases, the power generation torque increases in the region until the rotational speed reaches the rotational speed Nb. On the other hand, since the generated current is limited, the power generation torque is increased in the region where the rotational speed is higher than the rotational speed Nb. Get smaller.

  Subsequently, with respect to the power generation torque that can be generated by the second inverter power generation control, the power generation torque increases as the rotational speed decreases, and the power generation torque decreases as the rotational speed increases due to the power generation current restriction. Further, as the rotational speed increases, the loss in the switching element unit 21 increases as compared with the alternator power generation control due to the influence of switching on and off of the switching element according to the PWM signal. Therefore, in a region where the rotational speed is higher than the rotational speed Na, the power generation torque is smaller than in the alternator power generation control. Therefore, as shown in FIG. 8, there is an intersection P between the characteristic line of the power generation torque that can be generated by the alternator power generation control and the characteristic line of the power generation torque that can be generated by the second inverter power generation control.

  Therefore, by setting the rotation speed Na corresponding to the intersection point P to the second set rotation speed N2, when the rotation speed reaches the rotation speed Na, the second inverter power generation control is switched to the alternator power generation control. In this case, since the range of the power generation torque that can be generated by the second inverter power generation control and the range of the power generation torque that can be generated by the alternator power generation control coincide with each other, fluctuations in the power generation torque generated by switching can be suppressed.

  As described above, according to the second embodiment, when the power generation torque that can be generated by the second inverter power generation control and the power generation torque that can be generated by the alternator power generation control coincide with each other, The second set rotational speed N2 is switched from the power generation control to the alternator power generation control. Thereby, the fluctuation | variation of the electric power generation torque which generate | occur | produces by switching from 2nd inverter electric power generation control to alternator electric power generation control can be suppressed.

  DESCRIPTION OF SYMBOLS 1 Rotating electrical machine 2 Rotating electrical machine control device 3 DC power supply 4 Smoothing capacitor 11 Winding set 12 Rotation sensor 21 Switching element unit 22 Current sensor 23 Current command generator 24 Voltage command generator 25 Switching signal generation unit, 251 asynchronous PWM signal generation unit, 252 synchronous PWM signal generation unit, 253 synchronous rectification power generation control unit.

Claims (5)

A control device for a rotating electrical machine that performs switching control of a plurality of power generation methods according to the number of rotations of the rotating electrical machine when the rotating electrical machine having a winding set is driven as a generator,
A switching element portion in which a plurality of circuits each having a switching element on each of a high potential side and a low potential side are connected in parallel;
A voltage command generation unit that generates a phase voltage command to each phase of the winding set according to a control command to the rotating electrical machine, and outputs the generated phase voltage command;
A switching signal generation unit that generates a switching control signal and performs switching control of each switching element of the switching element unit on and off according to the generated switching control signal;
A current sensor for detecting a phase current flowing in each phase of the winding set;
A rotation sensor for detecting the number of rotations;
With
The switching signal generator is
An asynchronous carrier wave is generated so that the carrier frequency becomes a set carrier frequency, and an asynchronous PWM signal is generated by comparing the amplitude of the phase voltage command input from the voltage command generation unit and the generated asynchronous carrier wave. An asynchronous PWM signal generation unit for performing first inverter power generation control generated as the switching control signal;
The phase difference between the phase voltage command and the synchronous carrier wave is constant, and the synchronous carrier is sequentially changed in the decreasing direction from the initial number of pulses to one pulse in the phase voltage command with respect to one electrical angle cycle. A synchronous PWM signal generation unit that performs a second inverter power generation control that generates a wave and generates a synchronous PWM signal as the switching control signal by performing an amplitude comparison between the phase voltage command and the generated synchronous carrier wave;
A synchronous rectification power generation control unit that performs alternator power generation control that generates a synchronous rectification signal as the switching control signal in accordance with the polarity of the phase current detected by the current sensor;
Have
When the rotation speed detected by the rotation sensor is smaller than the first set rotation speed, the first inverter power generation control is performed, and when the rotation speed reaches the first set rotation speed, the first inverter power generation is performed. The control is switched from the control to the second inverter power generation control to perform the second inverter power generation control, and when the rotation speed reaches a second set rotation speed larger than the first set rotation speed, the second inverter power generation control A control device for a rotating electrical machine that further switches to the alternator power generation control and performs the alternator power generation control. The synchronous PWM signal generator is
In response to the rotation speed or the control command, the number of pulses for one electrical angle cycle of the phase voltage command is sequentially changed in a decreasing direction from the initial setting pulse number to one pulse,
The control device for a rotating electrical machine according to claim 1, wherein the control command is a current command or a torque command. 3. The rotating electrical machine according to claim 1, wherein when the rotational speed reaches the second set rotational speed and the phase voltage command becomes zero, the second inverter power generation control is further switched to the alternator power generation control. Control device. The rotation speed of the rotating electrical machine when the power generation torque that can be generated by the second inverter power generation control and the power generation torque that can be generated by the alternator power generation control coincide with each other is set as the second set rotation speed. 4. The control device for a rotating electrical machine according to any one of items 1 to 3. The control device for a rotating electrical machine according to any one of claims 1 to 4, wherein a hysteresis is provided in at least one of the first set rotation speed and the second set rotation speed.

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