JP7108834B2 - power generator - Google Patents

Description

The present invention relates to a power generator used as a power source for home electric appliances such as electric washing machines, air conditioners, and refrigerators used in general households, offices, businesses, and transportation.

Conventionally, there has been disclosed a power generating device that detects step-out by providing a first speed estimating unit and a second speed estimating unit that uses a different estimation method from the first speed estimating unit (see, for example, Patent Document 1). The first speed estimator estimates a rotational speed such that an axial error Δθ or Δθm of a rotor of an electric motor using permanent magnets converges to zero, and outputs a first estimated rotational speed. The second speed estimator controls the electric motor such that the first estimated rotation speed follows the speed command, and outputs a second estimated rotation speed estimated by a different estimation method.

FIG. 13 is a block diagram of a conventional power generation device described in Patent Document 1. As shown in FIG.

As shown in FIG. 13, the power generation device of Patent Document 1 includes an electric motor 1 having a permanent magnet, a PWM inverter 2, coordinate converters 3 and 4, a current control section 5, a speed control section 6, a magnetic flux control section 7, a It has a first speed estimator 8 , an integrator 9 , a second speed estimator 10 and an out-of-step determination unit 11 . A first speed estimator 8 estimates the rotation speed of the rotor of the electric motor 1 and controls the electric motor 1 so that the obtained first estimated rotation speed ωe follows the speed command ω*. The second speed estimator 10 estimates the rotation speed of the rotor of the electric motor 1 using an estimation method different from that of the first speed estimator 8 . The step-out determination unit 11 compares the estimated second estimated rotation speed ω2e obtained by the second speed estimation unit 10 with the first estimated rotation speed ωe or the speed command ω*. Then, step-out of the electric motor 1 is detected based on the comparison result, and the rotation of the electric motor 1 is controlled.

Further, when the motor is started, the input active power is calculated based on the correlation value of the current value input from the current detection unit and the voltage command value applied to the motor. A power generator that detects shaft lock (i.e., step-out) is disclosed (e.g.,
See Patent Document 2).

FIG. 14 is a block diagram of a conventional power generation device described in Patent Document 2. As shown in FIG.

As shown in FIG. 14 , the power generation device of Patent Document 2 has Idc and Iqc, which are correlation values of electric current values of the electric motor, and a voltage command value V*dc corresponding to the voltage applied to the electric motor, when the electric motor is started. V*qc is calculated by the input active power calculator 12 . The input active power calculation unit 12 outputs the obtained input active power value Pi to the shaft lock determination unit 13 . A speed command value ω1* is also input to the shaft lock determination unit 13 . When the inputted input active power value Pi is smaller than the threshold value under the condition of the speed command value ω1*, the shaft lock determination unit 13 determines that the shaft lock of the motor has occurred, and stops driving the motor. Let Thus, the power generation device of Patent Document 2 constitutes the shaft lock detection section 14 .

In other words, the above conventional power generation device is capable of decelerating when the speed of the motor having permanent magnets is considerably high, the induced electromotive force generated in the windings is sufficiently high, and the winding resistance and induction coefficient are relatively small. It is intended for tone detection. Therefore, if the above-described conditions are not met, there is a risk of making an erroneous determination in step-out detection. For example, as an erroneous judgment, there is a case where it is determined that there is a step-out even though it is in a normal operating state in which there is actually no step-out. Conversely, there are cases where it is determined that the engine is in a normal operating state even though it is actually out of step.

However, conventional power generators do not have a configuration for detecting out-of-step that can deal with erroneous determinations.

In other words, in the power generation device of Patent Document 1, when the induced electromotive force generated by the low-speed rotation of the electric motor is small, even if the axis error Δθ or Δθm is calculated to be a minute value near zero, The actual axis error may be large. In addition, when the winding resistance is large and torque is required during operation (powering), the voltage drop due to the winding resistance is large, and the variation due to the fluctuation of the winding resistance and the change in the winding resistance due to temperature also becomes large. Therefore, the reliability of the second estimated rotational speed estimated by the second speed estimator 10 is lowered. Specifically, it becomes impossible to make a determination from the voltage of the δ-axis component, for example.

That is, during operation (powering) that requires torque at low speed, the induced electromotive force generated by the rotation of the motor is small and the voltage drop due to the winding resistance is large. Furthermore, fluctuations due to fluctuations in winding resistance and changes in winding resistance due to temperature increase. As a result, the reliability of the second estimated rotational speed estimated by the second speed estimator 10 is lowered, making it difficult to determine, for example, the voltage of the δ-axis component.

Further, in the power generation device of Patent Document 2, similarly to the above, in the case of design specifications with large winding resistance, the reliability of shaft lock detection is lowered. Furthermore, when the torque required immediately after starting is large, the power consumed by the winding resistance (copper loss) increases regardless of whether the shaft is locked or not. Therefore, it becomes difficult to determine whether or not the shaft is locked based on the output difference of the input active power calculator 12 .

On the other hand, when the required torque is small, the input power to the motor when the shaft is not locked is also small. Therefore, it is difficult to determine the state of axis lock based on a smaller threshold than a small input power.

In recent years, more and more electric motors have aluminum wires instead of copper wires used for windings. Therefore, the winding resistance tends to increase further. This makes it even more difficult to determine the step-out.

There is also a power generating device in which a light-emitting element, a light-receiving element, a Hall element, or the like is provided in an electric motor, and signals relating to the speed and position of a permanent magnet are used as appropriate. That is, the power generator performs estimation by interpolating discrete speed/position information. However, when estimating while interpolating, there may be a delay in detection of step-out of the motor, and detection may be difficult. Therefore, it is difficult to determine whether the power generator is out of step.

JP 2007-282389 A JP 2013-146162 A

SUMMARY OF THE INVENTION The present invention provides a power generator capable of appropriately judging the out-of-step state of an electric motor and restarting it early when the out-of-step state is detected.

The power generator of the present invention supplies a current to the windings of the motor, and has a power supply circuit having a characteristic that the phase of the current to the permanent magnet differs when the magnitude of the electromotive force differs. It is configured to restart after sometimes changing the frequency of the current.

According to this configuration, it is possible to reduce erroneous detection of step-out even in the case of a specification in which the winding resistance of the motor is large, or in the case of driving conditions such as low speed and low induced electromotive force. In addition, the motor can be restarted appropriately and quickly from the out-of-step state. Accordingly, it is possible to provide a power generator capable of suppressing waste of electric energy and time.

FIG. 1 is a block diagram of a power generator according to Embodiment 1 of the present invention. FIG. 2 is a circuit diagram of an inverter circuit of the power generator in the same embodiment. FIG. 3 is a configuration diagram of an electric motor and a load in the same embodiment. FIG. 4 is a vector diagram of the power generator in the same embodiment. FIG. 5A is a velocity waveform diagram during normal operation of the power generator in the same embodiment. FIG. 5B is a velocity waveform diagram in a state in which step-out occurs during operation of the power generator according to the embodiment. FIG. 6A is a phase waveform diagram during normal operation of the power generator in the same embodiment. FIG. 6B is a phase waveform diagram in a state in which step-out occurs during operation of the power generator according to the embodiment. FIG. 7 is a vector diagram of the power generator in the same embodiment. FIG. 8 is a vector diagram of a power generator according to Embodiment 2 of the present invention. FIG. 9A is a velocity waveform diagram during normal operation of the power generator in the same embodiment. FIG. 9B is a velocity waveform diagram in a state in which step-out occurs during operation of the power generator according to the same embodiment. FIG. 10A is a phase waveform diagram during normal operation of the power generator in the same embodiment. FIG. 10B is a phase waveform diagram of a state in which step-out has occurred during operation of the power generator according to the same embodiment. FIG. 11 is a block diagram of a power generator according to Embodiment 3 of the present invention. FIG. 12 is a vector diagram of the power generator in the same embodiment. FIG. 13 is a block diagram of a conventional power generation device described in Patent Document 1. As shown in FIG. FIG. 14 is a block diagram of a conventional power generation device described in Patent Document 2. As shown in FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the present invention is not limited by this embodiment.

(Embodiment 1)
First, the configuration of the power generator according to Embodiment 1 of the present invention will be described with reference to FIG.

FIG. 1 is a block diagram of a power generator according to Embodiment 1 of the present invention.

As shown in FIG. 1, the power generator of the present embodiment includes an electric motor 18 having windings 15, 16 and 17, a power supply circuit 19 for supplying current to the windings 15, 16 and 17, and the like. .

The power supply circuit 19 includes a winding current control section 20 for controlling the currents of the windings 15, 16 and 17, a first electromotive force calculation section 21, an adder 22, a first predetermined value generation section 23, a speed signal generation section. 24, an integrator 25, a speed commander 26, a subtractor 27, a current command value generator 28, a restart signal generator 29, and the like. The winding current control section 20 includes subtractors 30 and 31, a voltage signal output section 32, a two-to-three phase conversion section 33, a current signal output section 34, an inverter circuit 35, and the like.

The power generator of this embodiment is configured as described above.

Next, the inverter circuit 35 of the power generator of this embodiment will be described with reference to FIG.

FIG. 2 is a circuit diagram of the inverter circuit 35 of the power generator of the same embodiment.

As shown in FIG. 2, the inverter circuit 35 includes a DC power supply 37, switching elements 38, 39, 40, 41, 42, 43, a drive circuit 44, a PWM modulation section 45a, a current detection section 46, and the like. . The DC power supply 37 is composed of a circuit for voltage doubler rectification of a 100 V AC commercial power supply, and outputs a DC voltage of about 280 V to the switching elements 38 , 39 , 40 , 41 , 42 and 43 , for example. The switching elements 38, 39, 40, 41, 42, 43 are composed of, for example, IGBTs (insulated gate bipolar transistors) with diodes connected between collector terminals and emitter terminals. Switching elements 38 and 41, switching elements 39 and 42, and switching elements 40 and 43 are each connected in series. Furthermore, the pair of switching elements 38, 41, the pair of switching elements 39, 42, and the pair of switching elements 40, 43 connected in series are connected in parallel with each other. The emitter terminal of each switching element 38,39,40 is connected to the collector terminal of the corresponding switching element 41,42,43. Three-phase voltages VU, VV, and VW of U, V, and W are output to the electric motor 18 from the respective connection points.

A drive circuit 44 is connected to respective gate terminals of the switching elements 38 , 39 , 40 , 41 , 42 , 43 . Drive circuit 44 drives switching elements 38, 39, 40, 41, 42, and 43 based on drive signals UP, UN, VP, VN, WP, and WN from PWM modulation section 45a included in microcomputer 45. ON/OFF driving is performed according to a predetermined order.

The current detection unit 46 includes shunt resistors 47, 48, and 49 connected to respective emitter terminals of the switching elements 41, 42, and 43 on the low potential side, an amplifier 50, and the like. The current detector 46 detects voltages generated in the shunt resistors 47 , 48 , 49 while the driving circuit 44 turns on the switching elements 41 , 42 , 43 . Amplifier 50 amplifies the sensed voltage. Then, it outputs to the microcomputer 45 an analog voltage signal corresponding to the current flowing through each of the three phases and IU, IV, and IW corresponding to its digital conversion value. Based on the input IU, IV, and IW, the microcomputer 45 outputs drive signals UP, UN, VP, VN, WP, and WN to the drive circuit 44 from the PWM modulation section 45a.

In addition to the above configuration, the current detection unit 46 detects a current value from a direct current from two or more phase windings out of three-phase windings with a core and a magnetic detection element, for example, DCCT (DC A configuration may be employed in which detection is performed by a method called Current Transformer.

Also, the current detection unit 46 may be configured with only one shunt resistor described above. In this case, the current value is detected individually during the ON time based on the corresponding relationship with the ON time of the switching element on the low potential side of each phase. As a result, all three-phase current values can be detected with only one shunt resistor.

As described above, the inverter circuit 35 of the power generator of the present embodiment is configured.

Next, the configuration of the electric motor 18 and the load 63 of the power generator of the present embodiment will be described with reference to FIG.

FIG. 3 is a configuration diagram of the electric motor 18 and the load 63 in the same embodiment.

As shown in FIG. 3, the electric motor 18 includes a first object 51, a second object 52, and so on. The first object 51 is generally called a stator and consists of windings 15,16,17. The second object 52 is generally called a rotor and is rotatably supported with respect to the first object 51 . The second object 52 is formed by bonding permanent magnets 56 , 57 , 58 , 59 to the surface of an iron core 55 , for example. In the present embodiment, the second object 52 is magnetized so that the outer sides of the permanent magnets 56 and 58 are N poles, and the outer sides of the permanent magnets 57 and 59 are S poles. be.

That is, the electric motor 18 is configured such that the second object 52 is rotatably arranged with respect to the first object 51 and can move relative to the first object 51 in the rotational direction. Therefore, the state of interlinkage between the magnetic fluxes from the permanent magnets 56, 57, 58, and 59 and the windings 15, 16, and 17 due to relative motion (that is, rotational motion) between the first and second objects is It changes depending on the angle of rotation. As a result, an electromotive force (or referred to as an induced electromotive force) is generated in the windings 15 , 16 and 17 that are the first object 51 .

The shaft 60 is configured integrally with the second object 52 and provided rotatably. Shaft 60 is connected to load 63 via coupling 61 and shaft 62 with clutches 65 , 66 . At this time, the torque of the second object 52 is transmitted to the load 63 by engaging the clutches 65 and 66 of the coupling 61 .

In the above embodiment, the first object 51 is fixed and the second object 52 is relatively moved (rotated), but the configuration is not limited to this. For example, the second object 52 may be fixed and the first object 51 may be moved relative to each other. In this case, the shaft 60 is preferably provided on the first object 51 . Furthermore, the relative motion may be a linear motion other than the rotational motion.

Further, in the above embodiment, the configuration in which the three-phase windings 15, 16, and 17 are provided in the first object 51 and the four permanent magnets 56, 57, 58, and 59 are provided in the second object 52 has been described as an example. However, it is not limited to this. For example, either the first object 51 or the second object 52 may be provided with both windings and permanent magnets. In this case, the other side has a configuration in which neither windings nor permanent magnets are provided. However, for example, it may be configured to have a claw pole or the like that constitutes a magnetic circuit. According to this configuration, relative motion between the first object 51 and the second object 52 changes the degree of interlinkage between the magnetic flux emitted from the permanent magnet and the winding. In other words, since an electromotive force can be generated by relative motion, the above configuration is also an effective configuration.

As described above, the electric motor 18 and the load 63 of the power generator of the present embodiment are configured.

Next, the control operation of the winding current control section 20 of the power generator having the above configuration will be described with reference to FIG.

The winding current control unit 20 of the power supply circuit 19 performs control by a method generally called vector control.

That is, the analog voltage signals supplied to the windings 15, 16, 17 of the electric motor 18 and IU, IV, IW corresponding to the digital conversion values thereof are output by the current signal output unit 34 to the estimated d-axis (γ-axis) and the estimated q 3-phase to 2-phase conversion is performed on the orthogonal coordinates of the axis (δ-axis). Then, the values of the voltage on the γ-axis and the δ-axis are converted through the two-to-three-phase converter 33 to control the electric motor 18 .

Specifically, the two-to-three-phase conversion unit 33 calculates an estimated d-axis voltage Vγ (hereinafter sometimes abbreviated as Vγ), an estimated q-axis voltage Vδ (hereinafter sometimes referred to as Vδ) and a phase signal θ which is an estimated phase output from an integrating section 25, which will be described later, are converted into Vu, Vv, and Vw. Note that Vγ corresponds to the first phase component of the winding voltage. Vu, Vv, and Vw in formula (1) are synonymous with VU, VV, and VW described above.

The current signal output unit 34 calculates an estimated d-axis current Iγ (hereinafter sometimes abbreviated as Iγ) and an estimated q-axis current Iδ (hereinafter sometimes abbreviated as Iγ) from Iu, Iv, and Iw and the phase signal θ using equation (2). , Iδ), that is, three-phase to two-phase conversion. Note that Iγ corresponds to the first phase component of the winding current, and Iδ corresponds to the second phase component of the winding current. Iu, Iv, and Iw in formula (2) are synonymous with IU, IV, and IW described above.

As noted above, vector control first divides the current into two components in rectangular coordinates. Then, the voltage component on the orthogonal coordinates is adjusted and controlled so that each of the two current components has a predetermined value. Therefore, the winding current control unit 20 of the power supply circuit 19 of the present embodiment is highly applicable to the above vector control configuration. As a result, it is possible to operate the power generator while appropriately suppressing the phase shift to near zero.

Specifically, the winding current control unit 20 outputs an estimated d-axis current command value Iγr (hereinafter sometimes abbreviated as Iγr) and an estimated q-axis current command value Iδr (hereinafter sometimes abbreviated as Iγr) from the current command value generation unit 28 , Iδr). Note that Iγr corresponds to the first current command value, and Iδr corresponds to the second current command value.

Then, the winding current control unit 20 adjusts Vγ and Vδ so that the error between Iγ and Iδ output from the current signal output unit 34 and the received Iγr and Iδr becomes zero. That is, the winding current control section 20 operates as an error amplifier.

Note that the estimated d-axis current command value Iγr is set to zero in the present embodiment. As a result, for example, in a surface magnet motor (SPM) configured by bonding permanent magnets 56, 57, 58, and 59 to the surface of an iron core 55, the d-axis current, which is not involved in torque generation (power generation), is zero. not). As a result, the required torque can be secured with the minimum current value. Therefore, loss due to current in the winding, ie copper loss, can be minimized. As a result, highly efficient operation of the surface magnet motor is possible. At this time, the estimated d-axis current Iγ becomes almost zero. As a result, the operation of the electric motor 18 can be controlled with the value of the estimated q-axis current Iδ adjusted according to the required torque.

That is, in the present embodiment, Vγ and Vδ are adjusted so that Iγ and Iδ, which are two components of the orthogonal coordinate γδ rotating in synchronization with the phase signal θ, are equal to Iγr and Iδr, respectively. . Finally, the inverter circuit 35 adjusts the three-phase voltages VU, VV, and VW applied to the windings 15, 16, and 17 forming the first body 51 of the electric motor 18. FIG.

As described above, the winding current control section 20 of the power generator operates.

Next, the operation of generating the speed signals ω1 and ω2 and the phase signal θ of the electric motor 18 will be described.

First, the first electromotive force calculator 21 shown in FIG. 1 calculates a first electromotive force εγ (hereinafter referred to as (sometimes abbreviated as εγ). Note that εγ corresponds to the first phase component of the electromotive force.

Here, Ra is the resistance value of the windings 15, 16 and 17, and L is the inductance value (induction coefficient) of the windings 15, 16 and 17. At this time, both the resistance value Ra and the inductance value L are values on rectangular coordinates.

Electric motor 18 of the present embodiment is configured to have permanent magnets 56 , 57 , 58 , 59 on the surface of iron core 55 . Therefore, the inductance value L can be expressed as a constant value. However, in the case of a motor configuration in which permanent magnets are embedded deep in the iron core, the inductance value L varies with the phase (angle) in the dq coordinates. In this case, the first electromotive force εγ of the γ-axis component is calculated using the inductance value Lq on the q-axis instead of the inductance value L in the above equation (3).

In addition, in Equation (3), if Iγ is set to zero and the electric motor 18 is controlled with a value close to its command value, the second term on the right side may be omitted in some cases. Also, p indicating time differentiation may be omitted if not necessary. Furthermore, for low speed conditions where ω is small, the third term of equation (3) may be omitted. That is, in the equation (3), the first electromotive force εγ can be obtained by appropriately selecting elements within a range within a sufficient phase shift.

Here, the phase relationship between current and voltage during operation of the power generator will be described with reference to FIG.

FIG. 4 is a vector diagram in a normal operating state in the power generator of the same embodiment.

In FIG. 4, vector A indicates an electromotive force vector when the electromotive force is large, vector B indicates an electromotive force vector when the electromotive force is small, and vector I indicates a current vector.

In the present embodiment, the speed signal generator 24 shown in FIG. 1 decreases the speed signals ω1 and ω2 when the input value μ is positive. On the other hand, when the input value μ is negative, the speed signal generator 24 functions to increase the speed signals ω1 and ω2. The integrator 25 time-integrates the speed signal ω1 from the speed signal generator 24 to generate the phase signal θ. The phase signal θ is input to the two-to-three phase conversion section 33 and the current signal output section 34 . As a result, in the steady state, the velocity signal generator 24 operates to keep the input value μ at a very small value close to zero.

In this embodiment, the speed signals ω1 and ω2 are estimated speed signals due to sensorless control. Specifically, the speed signal ω1 is a value for the purpose of speed control. On the other hand, the speed signal ω2 is a value intended to keep the phase signal θ, which is the integrated value of the integrating section 25, stable. In other words, since the speed signals ω1 and ω2 have different purposes, they are slightly different so that the error amplification gain and the response to the input value μ can be optimized. At this time, the lower limit values of the speed signals ω1 and ω2 are set to zero.

The input value μ is obtained by adding the output Vb of the first predetermined value generating section 23 and the output value εγ of the first electromotive force calculating section 21 (corresponding to the first electromotive force in equation (3)). It is the value added by the unit 22 . Therefore, in a steady state in which the electric motor 18 is not out of step and normally operated, feedback control is performed so that the γ component (that is, the output value εγ) of vector A and vector B shown in FIG. 4 becomes -Vb. state.

In this embodiment, the first predetermined value is set to a positive value such as the output Vb of the first predetermined value generator 23=+0.5V. Therefore, both vector A and vector B shown in FIG. 4 are vectors tilted to the left. At this time, compared with vector A having a large electromotive force, vector B having a small electromotive force becomes a vector tilted further to the left.

In this case, the electromotive force vectors A and B are generated by the permanent magnets 56 , 57 , 58 , 59 and the winding 15 due to the relative motion (rotational motion) between the first body 51 and the second body 52 of the electric motor 18 . , 16 and 17 are generated by the temporal change of the flux linkage. That is, vector A and vector B always occur on the q-axis.

At this time, the q-axis for vector A and vector B are the qA-axis and the qB-axis, respectively. On the other hand, the d-axis for vector A and vector B is the dA-axis and the dB-axis that are 90 degrees behind the q-axis.

As shown in FIG. 4, both vector A and vector B are in the counterclockwise direction indicated by arrow G from the .delta.-axis. That is, the q-axis leads the δ-axis in phase. In other words, the δ-axis lags the q-axis in phase in the clockwise direction indicated by the arrow H. Therefore, it can be expressed that the estimated phase signal θ is delayed. Moreover, vector B is more in the counterclockwise direction than vector A. Therefore, the vector B has a larger delay of the phase signal θ than the vector A.

On the other hand, the current vector I (hereinafter sometimes referred to as current I) is Iγr=0 as described above. Therefore, the current vector I is always controlled on the δ axis. That is, the orthogonal coordinates (dB, qB) for vector B with a small electromotive force lag the orthogonal coordinates (dA, qA) for vector A with a large electromotive force in phase with the current vector I.

Here, the magnitude of the electromotive force E [V] generated in the winding due to the rotation of the permanent magnet is expressed by Equation (4). That is, the electromotive force E [V] is the speed of the relative motion between the first object 51 and the second object 52, that is, the operating speed (rotational speed) of the electric motor 18, expressed as the electrical angular velocity ω [rad/s]. value and the magnetic flux Ψa [Wb] of the permanent magnets 56 , 57 , 58 , 59 .

Therefore, the power supply circuit 19 has the characteristic that the phase of the current to the permanent magnet differs when the electromotive force E differs.

Here, in the power supply circuit 19, the following three confirmation methods are exemplified as methods for confirming that the phases of the currents differ when the electromotive force E differs.

A first confirmation method is to perform a test in which the electrical angular velocity ω is changed, and to change the operating speed of the electric motor 18 . In this case, even if the magnetization state of the permanent magnet is constant, the electromotive force E changes in proportion to the electrical angular velocity ω when the operating speed is changed between high and low. Therefore, the phase of the current I on the dq plane, that is, the change in the phase of the current I with respect to the permanent magnet is confirmed. At this time, if a change in the phase of the current is confirmed, it can be determined that the configuration of the power supply circuit 19 of the present embodiment is functioning effectively.

In the second confirmation method, first, two electric motors having different magnetization strengths of permanent magnets and different values of magnetic flux Ψa are prepared. Then, the motor is tested at the same speed, ie, the same electrical angular velocity ω, and the same load.

As in the second confirmation method, the third confirmation method first prepares two electric motors having different values of the magnetic flux Ψa. Then, the test is performed by adjusting the load torque so that the magnitude of the current is constant while setting the electric motor at the same speed, that is, the same electrical angular velocity ω.

In other words, in the case of the second and third confirmation methods, the values of the magnetic flux Ψa are different, so even with the same electrical angular velocity ω, the electromotive force E is different. At this time, if a change in the phase of the current I with respect to the permanent magnet can be confirmed, it can be judged that the configuration of the power supply circuit 19 of the present embodiment is functioning effectively.

In addition, in the case of the second and third confirmation methods, as described above, confirmation is performed under the conditions of the same speed (ω value) and different magnitudes of the electromotive force E. FIG. Therefore, for example, in the case of a configuration in which an element in which the phase of the current I on the estimated coordinates is changed as a function of the electrical angular velocity ω is added, whether the components of the power supply circuit 19 of the present embodiment function effectively may be difficult to confirm. However, even in the case of the configuration in which the element that changes the phase of the current I is added, the configuration of the power supply circuit 19 of the present embodiment functions reliably through tests under conditions where the magnitude of the electromotive force E is different. It is useful to confirm that

In the second confirmation method, when the degree of magnetization strength of the permanent magnet is different, the phenomenon that the Iq value changes occurs, that is, the load torque appears under a constant condition. impact occurs. That is, in the second confirmation method, since the load is the same, the magnitude of the current I (absolute value of the vector) changes due to the difference in magnetization strength (the magnitude of the torque with respect to the current, that is, the torque constant). different values. Therefore, an influence such as an error in the calculation of the first electromotive force occurs. However, according to the third confirmation method, since the above influence can be removed, appropriate confirmation becomes possible.

In addition, in the second and third confirmation methods, the strength of magnetization of the permanent magnet can be confirmed by the following method.

First, the drive motor and the shaft of the motor to be tested are connected via a coupling or the like. In the connected state, the two motors are rotated at the same speed. At this time, the voltage between the open input terminals is measured or observed with a measuring instrument such as a voltmeter, a digital power meter, or an oscilloscope. This makes it possible to confirm the strength of the magnetization of the permanent magnet.

Further, in the first to third confirmation methods, the phase of the current I to the permanent magnet can be confirmed by the following method.

First, for example, an optical ABZ rotary encoder is attached to the shaft of an electric motor. At this time, the origin of the ABZ rotary encoder is made coincident with the electrical angle θ=0, that is, the phase in the same direction as the magnetic flux generated by the magnetomotive force supplied from the N pole and the U phase. Then, the phase of the current vector I from the current waveform of one phase or the current values of the three phases is analyzed. This makes it possible to confirm the phase of the current I with respect to the permanent magnet.

In addition, in the first to third confirmation methods, the frequency of the current can be confirmed with an oscilloscope or the like. The confirmed frequency of the current becomes a speed signal that is the estimated speed ω2 inside the power supply circuit 19 .

As described above, if the difference in the phase of the current I due to the difference in the electromotive force E is confirmed by any of the first to third confirmation methods, the configuration of the power supply circuit 19 of the present embodiment functions. can confirm that there is

That is, at the time of step-out, the phase of the current I to the permanent magnet changes from that before step-out in the process in which the rotation of the electric motor 18 decreases to zero. This causes the frequency of the current to fluctuate (ie the estimated speed to decrease or increase). As a result, it is possible to obtain the effect of the present invention that it is possible to appropriately detect the step-out of the electric motor 18 from the change in the estimated speed.

Further, in the present embodiment, the motor with weaker magnetization of the permanent magnet has an advanced phase (arrow G) in the d-axis and the q-axis, as indicated by the vector B shown in FIG. Therefore, the phase of the current I with respect to the dq coordinates tends to lag behind (arrow H).

As a result, whether or not the configuration of the power supply circuit 19 of the present embodiment is properly established can be properly confirmed as described below.

Specifically, when the permanent magnets 56, 57, 58, and 59 are in a standard magnetized state, rotating the electric motor 18 at a speed of 35 r/min, for example, generates an electromotive force E of 5 V, for example. In this case, the phase of the current I lags behind the q-axis by 5.7 degrees. On the other hand, when the electric motor 18 is rotated under the same conditions with the strength of magnetization of the permanent magnet reduced by 30%, for example, an electromotive force E of 3.5 V is generated. . In this case, the phase lag of the current I from the q-axis is 8.2 degrees. That is, the phase of the current I is further delayed by 2.5 degrees due to the 30% drop in the electromotive force E. Thereby, it can be confirmed that the configuration of the power supply circuit 19 of the present embodiment is established normally.

Next, speed control of the electric motor 18 during operation of the power generator will be described with reference to FIGS. 5A and 5B.

FIG. 5A is a velocity waveform diagram during normal operation of the power generator in the same embodiment. FIG. 5B is a velocity waveform diagram in a state in which step-out occurs during operation of the power generator according to the embodiment. That is, FIG. 5A shows the velocity waveform in the normal state, that is, in a steady state without step-out. On the other hand, FIG. 5B shows the speed waveform when the speed of the electric motor 18 is suppressed to zero in the middle of the operation due to, for example, an overload, and out of step. In FIGS. 5A and 5B, the command speed is indicated by a dashed line, and the speed signal ω2, which is the estimated speed, is indicated by a solid line.

The power generator shown in FIG. 5A has sufficient speed control. Therefore, it can be seen that the speed signal ω2 is kept around 35 r/min, which is substantially the same as the command speed.

On the other hand, the power generator shown in FIG. 5B is overloaded at t=t1, and the speed of the electric motor 18 becomes zero. At this time, the speed signal .omega.2 gradually decreases to the lower limit of zero at t=t2. Then, at the timing of t=t2, the power supply circuit 19 detects that the electric motor 18 is out of step.

When the out-of-step state is detected, the restart signal generator 29 shown in FIG. After that, the restart signal generator 29 outputs a restart command to the speed command unit 26 within a predetermined time after t=t2. As a result, the motor 18, which has been out of step, is restarted from zero speed and returns to normal speed.

Here, the reason why the speed signal ω2 decreases when the speed of the electric motor 18 becomes zero will be explained below.

First, when the electromotive force becomes zero, there is no solution for the speed signal ω2 that keeps the γ component (Vb) of the electromotive force E at -0.5V as indicated by vectors A and B in FIG. The absence of a solution means that there is no phase where the γ component (first electromotive force εγ) is -0.5V in any phase of the electromotive force E on the γδ plane. Therefore, the direction of the arrow G shown in FIG. 4, ie, the phase of the current I from the q-axis is gradually delayed. As a result, the speed signal ω2, which is the estimated speed, finally becomes zero.

Further, in the electric motor 18 of the present embodiment, the electromotive force E is 0.5 V when the actual operating speed is 4 r/min. Therefore, when the operating speed further decreases from 4 r/min due to step-out, the above-described "no solution" state is assured.

At this time, the estimated speed corresponding to the speed signal ω2 is observed from the outside as the frequency of the current, as described above. Therefore, as a threshold value for determining the occurrence of step-out, for example, the point in time when the operating speed state of 3 r/min or less continues for 0.5 seconds can be set.

Note that the threshold is not limited to the above, and can be arbitrarily set. For example, the difference between the command speed and the estimated speed ω2, or the point in time when the absolute value of the difference becomes large, may be set as the threshold. In other words, if the difference between the command speed and the estimated speed ω2 is different from zero by the threshold value or more regardless of the sign, step-out detection is executed. Alternatively, the threshold may be set at a point in time when the commanded speed is multiplied by a predetermined ratio and the threshold speed exits the range, or at a point in time when the duration of these states reaches a predetermined time. Furthermore, a time integral of the difference between the command speed and the estimated speed may be set as the threshold. In other words, it is possible to set various threshold values according to the state of the applied power generator.

Further, in the above embodiment, the lower limit of the speed signal ω2, which is the estimated speed, is set to zero, and step-out is detected when the speed signal ω2 becomes zero. However, the present invention is not limited to this. For example, both the positive and negative values of the estimated speed are valid values, and the positive and negative values can be taken depending on the direction of rotation. Then, step-out may be detected when the positive/negative sign of the estimated speed changes. Even in this case, step-out may be detected by setting a restriction that prohibits the estimated speed from becoming opposite in sign. Further, it may be configured to detect step-out when the sign of the estimated speed becomes opposite to that of the estimated speed or when this state continues for a predetermined time. In other words, the above configuration is also effective for detecting out-of-step in the present embodiment.

Further, in the above-described embodiment, the configuration in which the speed signal ω2, which is the estimated speed, is externally measured as the frequency of the current has been described as an example. Specifically, for example, at least one line current of the three-phase electric motor 18 is measured using a measuring instrument such as a current probe and an oscilloscope. As a result, the estimated frequency of the measured line current can be used as the speed signal ω2, which is the estimated speed.

Next, phase waveforms of the electric motor 18 during operation of the power generator will be described with reference to FIGS. 6A and 6B.

FIG. 6A is a phase waveform diagram during normal operation of the power generator in the same embodiment. FIG. 6B is a phase waveform diagram in a state in which step-out occurs during operation of the power generator according to the same embodiment. That is, FIG. 6A shows the phase waveform in the normal state, that is, in a steady state without step-out. On the other hand, FIG. 6B shows the phase waveform when the speed of the electric motor 18 is suppressed to zero in the middle of the operation due to, for example, an overload, and is out of step. Specifically, FIGS. 6A and 6B show waveform diagrams of the phase of the current I with respect to the q-axis.

As shown in FIG. 6A, the power generator is in a state where the phase lag of the current I has a constant lag of approximately 5.7 degrees in the steady state.

On the other hand, as shown in FIG. 6B, when step-out occurs at t=t1, the phase lag of the current I gradually increases after t=t1. Then, at the time t=t2 when the speed signal ω2=0, the phase delay of the current I stabilizes at a constant value of 85 degrees, for example, as shown below. The phase lag of the current I is the value obtained by time-integrating the difference (speed difference) between the actual speed and the estimated speed ω2, as described above. That is, when the motor is out of step, the actual speed and the estimated speed ω2 become zero, so the speed difference becomes zero. As a result, the time integral of the velocity difference also becomes zero. As a result, a phenomenon in which the phase changes with time does not occur, and the phase difference converges to a constant value.

That is, in the power generator of the present embodiment, the phase delay of the current I from the q-axis settles at a constant value during normal operation and during out-of-step. That is, for example, even if a monitoring time is provided after t=t2 shown in FIG. 6B to determine whether the state of the speed signal ω2=0 continues, the phase delay of the current I with respect to the q-axis during the monitoring time is constant. . Therefore, sufficient time such as 0.2 seconds can be set as the monitoring time. This makes it possible to more reliably detect out-of-step. Moreover, since the phase delay of the current I settles down to a constant value, noise generation is suppressed.

The noise is generated, for example, by the continued rotation of the current vector, that is, by the positive and negative alternating torque acting on the mechanism when there is rotation on the dq plane. Therefore, if the phase delay is kept constant, no alternating torque will be generated, and static (direct current) torque will suffice. This eliminates one of the noise generating elements. As a result, noise generation can be suppressed.

Another example of the control operation of the power generator of the present embodiment will be described below with reference to FIG.

FIG. 7 is a vector diagram in a normal operating state in the power generator of the same embodiment. Specifically, it is a vector diagram in a state in which the setting of the current command value generator 28 shown in FIG. 1 is slightly changed from that in FIG.

In other words, as shown in FIG. 7, the current command value generator 28 sets the current I in the second quadrant on the γδ coordinates, not on the δ axis. Specifically, for example, the estimated d-axis current command value Iγr is set to −0.1A and the estimated q-axis current command value Iδr=+1.0A. In other words, the current I is set so as to lead the phase by 5.7 degrees with respect to the δ axis. As a result, the phase of the current I substantially coincides with the q-axis. That is, the phase of the electromotive force E and the phase of the current I match. At this time, the phase of the current I has a delay of 5.7 degrees with respect to the dq coordinates on the γδ coordinates. On the other hand, the phase of the current I matches the phase of the electromotive force E of the motor 18 . In this case, since the magnitude (vector length) of the current I is minimized, losses such as copper loss are minimized. Thereby, the electric motor 18 can be driven with high efficiency.

That is, as compared with the vector control shown in FIG. 4, the efficiency reduction and the step-out tolerance reduction due to the phase delay of the current I are suppressed. As a result, it is possible to realize a power generator with higher efficiency and higher stability.

Even in this case, if different electromotive forces are provided at the same speed, the phase of the current I with respect to the q-axis determined by the permanent magnets 56, 57, 58, and 59 will be is delayed as the electromotive force becomes smaller. That is, the drop in electromotive force and the change in the phase delay of the current I are the same as in the case of FIG.

Also, the operation when the electric motor 18 is out of step is the same as the operation described with reference to FIGS. 5A and 5B. That is, step-out is detected when the speed signal ω2 becomes zero. Then, the electric motor 18 can be restarted via the restart signal generator 29 shown in FIG. This can reduce the generation of noise, unnecessary current, or unnecessary time.

In the above-described embodiment, an example of a configuration in which Vb is added to εγ and feedback control is performed so that the input value μ=0 has been described, but the present invention is not limited to this. For example, the difference between εγ and −0.5V may be used as the error voltage, and feedback control may be performed so that the error voltage becomes 0V. Even in this case, control can be performed with the same operation as in the above embodiment. Therefore, both are effective as a configuration of feedback control.

As described above, the power generator of the present embodiment includes the windings 15, 16, and 17 forming the first object 51, the permanent magnets 56, 57, and 58 forming the second object 52, 59. Further, the power generator includes the electric motor 18 that generates an electromotive force in the windings due to the relative motion of the first object 51 and the second object 52, and the electric motor 18 that supplies current to the windings and the magnitude of the electromotive force is different. It has a power supply circuit 19 having characteristics in which the currents to the permanent magnets are out of phase. The power supply circuit 19 is configured to restart the electric motor 18 after changing the current frequency (estimated speed ω2) at the time of step-out from that before step-out. As a result, it is possible to appropriately determine the occurrence of a step-out state in a short time even under the condition that the winding resistance is large and the speed is low. Then, when the out-of-step state is detected, the engine can be restarted early to recover the original function of the power generator.

On the other hand, if it takes a long time to detect a state of out-of-step under low-speed conditions, the stop time of the power generator becomes longer. Therefore, the completion of the operation of the power generation device is delayed according to the stop time, and the time until restarting becomes longer. As a result, loss of electrical energy and time occurs.

That is, according to the configuration of the present embodiment, it is possible to determine the occurrence of a step-out state in a short time and restart the engine even under low-speed conditions, thereby suppressing the loss of electrical energy and time.

(Embodiment 2)
A power generator according to Embodiment 2 of the present invention will be described below with reference to FIG. 1 and FIG. 8 .

FIG. 8 is a vector diagram in a normal operating state of the power generator according to Embodiment 2 of the present invention.

The power generator of the present embodiment differs from the first embodiment in that the output Vb of the first predetermined value generator 23 is set to -0.5 V (equivalent to the first predetermined value), ie, a negative value. different. Other parts are equivalent to the constituent elements of the first embodiment.

In FIG. 8, vector A is an electromotive force vector when the electromotive force is large, vector B is an electromotive force vector when the electromotive force is small, and vector I is a current vector.

In the present embodiment, the speed signal generator 24 shown in FIG. 1 decreases the speed signals ω1 and ω2 when the input value μ is positive. On the other hand, when the input value μ is negative, the speed signal generator 24 has a function of increasing the speed signals ω1 and ω2. The integrating section 25 shown in FIG. 1 time-integrates the speed signal ω1 from the speed signal generating section 24 to generate the phase signal θ.
The phase signal θ is input to the two-to-three phase conversion section 33 and the current signal output section 34 . As a result, in the steady state, the velocity signal generator 24 operates to keep the input value μ at a very small value close to zero.

In this embodiment, the first predetermined value is set to a negative value such as the output Vb of the first predetermined value generator 23=-0.5V. At this time, -Vb=+0.5V. Therefore, vector A and vector B shown in FIG. 8 are both vectors tilted to the right. At this time, compared with vector A having a large electromotive force, vector B having a small electromotive force is a vector tilted further to the right. That is, the vector B is on the delayed side of the arrow H direction more than the vector A. Therefore, the vector B leads the phase signal θ more than the vector A.

On the other hand, the current vector I (hereinafter sometimes referred to as current I) is Iγr=0 in the present embodiment as in the first embodiment. Therefore, the current vector I is always controlled on the δ axis. That is, the orthogonal coordinates (dB, qB) for vector B with a small electromotive force lead the current vector I in phase relative to the orthogonal coordinates (dA, qA) for vector A with a large electromotive force.

It should be noted that confirmation of whether or not the configuration of the vector control of the present embodiment is correct can be similarly confirmed by the test using the electric motor 18 having different magnetization strengths of the permanent magnets, as described in the first embodiment. , explanation is omitted.

Next, speed control of the electric motor 18 during operation of the power generator will be described with reference to FIGS. 9A and 9B.

FIG. 9A is a velocity waveform diagram during normal operation of the power generator in the same embodiment. FIG. 9B is a velocity waveform diagram in a state where step-out occurs during operation of the power generator according to the same embodiment. That is, FIG. 9A shows the velocity waveform in the normal state, that is, in a steady state without step-out. On the other hand, FIG. 9B shows the speed waveform when the speed of the electric motor 18 is suppressed to zero in the middle of the operation due to an overload or the like, and out of step. In FIGS. 9A and 9B, the command speed is indicated by a dashed line, and the speed signal ω2, which is the estimated speed, is indicated by a solid line.

The power generator shown in FIG. 9A has sufficient speed control. Therefore, it can be seen that the estimated speed ω2 is kept around 35 r/min, which is substantially the same as the command speed.

On the other hand, the power generator shown in FIG. 9B is overloaded at t=t1, and the speed of the electric motor 18 becomes zero. At this time, the speed signal ω2 gradually increases and reaches, for example, 150 r/min, which is the threshold value for out-of-step detection, at t=t2. Then, at the timing of t=t2, the power supply circuit 19 detects that the electric motor 18 is out of step.

When the out-of-step state is detected, the restart signal generator 29 shown in FIG. After that, the restart signal generator 29 outputs a restart command to the speed command unit 26 within a predetermined time after t=t2. As a result, the motor 18, which has been out of step, is restarted from zero speed and returns to normal speed.

The reason why the speed signal ω2 increases when the speed of the electric motor 18 becomes zero will be explained below.

First, when the electromotive force E becomes zero, there is no solution for the speed signal ω2 that keeps the γ component (Vb) of the electromotive force at +0.5V as indicated by vectors A and B in FIG. Note that the absence of a solution means that there is no phase where the γ component (first electromotive force εγ) is +0.5 V in any phase of the electromotive force on the γδ plane. Therefore, the direction of the arrow H shown in FIG. 8, that is, the phase of the current I from the q-axis advances steadily. As a result, the speed signal ω2, which is the estimated speed, continues to rise. Ultimately, the speed signal ω2 rises to the threshold value (150 r/min) for determining the presence or absence of step-out.

Next, phase waveforms of the electric motor 18 during operation of the power generator will be described with reference to FIGS. 10A and 10B.

FIG. 10A is a phase waveform diagram during normal operation of the power generator in the same embodiment. FIG. 10B is a phase waveform diagram of a state in which step-out occurs during operation of the power generator according to the embodiment. In other words, FIG. 10A shows the phase waveform in the normal state, that is, in a steady state without step-out. On the other hand, FIG. 10B shows the phase waveform when the speed of the electric motor 18 is suppressed to zero in the middle of operation due to an overload or the like, resulting in a step-out state. Specifically, FIGS. 10A and 10B show waveform diagrams of the phase of the current I with respect to the q-axis.

As shown in FIG. 10A, in the steady state of the power generator, the phase of the current I has a constant lead of approximately 5.7 degrees.

On the other hand, as shown in FIG. 10B, when step-out occurs at t=t1, the phase lead of current I gradually increases after t=t1.

In the electric power generator of the present embodiment, when step-out occurs, the phase advance of the current I from the q-axis increases infinitely. Therefore, when the speed signal .omega.2 or .omega.1, which is the estimated speed, exceeds a predetermined value (for example, 150 r/min corresponding to a threshold value), it is determined that the motor has stepped out.

At this time, the estimated speed is greater than the commanded speed, so the absolute value of the current I is suppressed. Therefore, in terms of the phase of the current I, as indicated by the dashed line after t2 in FIG. 10B, even if the phase fluctuates significantly, noise rarely becomes a problem. That is, step-out can be detected within a period of small current value. In the case of this embodiment, unlike the first embodiment, the phase difference diverges. converge. Therefore, noise is reduced.

In the above-described embodiment, the threshold value of the speed signal ω2 or ω1, which is the estimated speed, is set to 150 r/min, and when the threshold value exceeds the predetermined value, it is immediately determined to be out of step. Illustrated, but not limited to. For example, the second phase component εδ of the electromotive force E shown in equation (5) may be calculated, and step-out may be detected if the calculated value is equal to or less than a second predetermined value.

That is, when the estimated speed is high to some extent, it is determined whether or not the second phase component εδ of the electromotive force is out of step. This makes it possible to determine step-out with sufficiently high accuracy. As a result, highly reliable step-out detection can be realized. The estimated speed to some extent is a speed that can be reliably detected as the electromotive force E even if there are errors in each element on the right side of Equation (5) (detection errors, parameter setting errors, and variations). be. Specifically, for example, the speed is E=10V.

Note that the term p indicating time differentiation may be omitted from equation (5) as well, as described in equation (3) of the first embodiment. Furthermore, when the ratio of the ω term is low during low-speed rotation, the third term of Equation (5) may be omitted to simplify the calculation formula.

(Embodiment 3)
The configuration of the power generator according to Embodiment 3 of the present invention will be described below with reference to FIG. 11 .

FIG. 11 is a block diagram of a power generator according to Embodiment 3 of the present invention.

As shown in FIG. 11, in the power generator of the present embodiment, the voltage signal output section 74 and the current signal output section 75 are mainly not included in the winding current control section 70 in the power supply circuit 69. It differs from the first embodiment in that Other components are the same as the components of the first embodiment, so they will be described with the same reference numerals.

In other words, the power generator of the present embodiment is composed of the electric motor 18 equivalent to that of the first embodiment, the power supply circuit 69 for supplying current to the electric motor 18, and the like.

Power supply circuit 69 includes a winding current control section 70 and the like, and winding current control section 70 includes a current error amplifier 71 and a three-phase to two-phase conversion section 72 . Note that the current error amplifier 71 is equivalent to the voltage signal output section 32 of the first embodiment. Also, the three-phase to two-phase conversion section 72 is equivalent to the current signal output section 34 of the first embodiment.

That is, in the power supply circuit 69 of the present embodiment, the voltage signal output section 74 and the current signal output section 75 are provided separately from the winding current control section 70 as described above. Therefore, the voltage signal output section 32 and the current signal output section 34 are changed to different names and given new reference numerals to be referred to as a current error amplifier 71 and a three-phase two-phase conversion section 72 .

The voltage signal output unit 74 of the power supply circuit 69 performs three-phase to one-phase conversion using a calculation formula substantially equivalent to the formula (2) described in the first embodiment. The difference from equation (2) is that the inputs are voltage signals Vu, Vv, and Vw instead of the currents Iu, Iv, and Iw. As a result, the calculation results on the left side are Vγ and Vδ instead of Iγ and Iδ. At this time, since the voltage signal output unit 74 performs three-phase to one-phase conversion, only Vγ, which is not used, is calculated as the calculation result of the left side without Vδ that is not used.

The configuration of the current signal output section 75 of the power supply circuit 69 is equivalent to the current signal output section 34 and the three-to-two phase conversion section 72 of the first embodiment.

The power supply circuit 69 of this embodiment also includes an adder 76 and a phase value source 77 .

Then, the current error amplifier 71 and the three-phase two-phase converter 72 add Δθ (=+5.7 degrees) to the phase signal θ1, which is the output value of the integration unit 25, by the adder 76 and the phase value source 77. A phase signal θ2 is input.

Components other than those described above function in the same manner as in the first embodiment.

The power generator of this embodiment is configured as described above.

The phase relationship between current and voltage and the control operation during operation of the power generator will be described below with reference to FIG. 12 .

FIG. 12 is a vector diagram in a normal operating state in the power generator of the same embodiment.

In the power generation apparatus of the present embodiment, the phase signal .theta.1 as the first estimated phase and the phase signal .theta.2 as the second estimated phase are used as the estimated phase in the power supply circuit 69. exists. The value of the phase signal .theta.2 becomes a large value by adding 5.7 degrees corresponding to the output value .DELTA..theta. of the phase value source 77 to the value of the phase signal .theta.1. Therefore, the phase signal .theta.2 has a value that leads the phase signal .theta.1.

Therefore, in the vector diagram of FIG. 12, the orthogonal coordinates for the phase signal .theta.1 are .gamma.1 and .delta.1, and the orthogonal coordinates for the phase signal .theta.2 are .gamma.2 and .delta.2.

In this case, the operation described in the first embodiment is performed for the phase signal θ1. Therefore, when Vb=+0.5 V, the coordinate axes of γ1 and δ1 at 35 r/min of the electromotive force vector A of the permanent magnets 56, 57, 58, and 59 having standard magnetization strength are The state is exactly the same as the γ and δ axes in form 1 of . That is, the phase signal θ1, which is the estimated phase, has a phase delay of 5.7 degrees, as in the first embodiment.

On the other hand, +5.7 degrees, which is the output value Δθ of the phase value source 77, is added by the adder 76 to the phase signal θ2, which is the second estimated phase. Therefore, the phase signal θ2 cancels the phase delay of 5.7 degrees that the phase signal θ1 has.

As a result, as shown in FIG. 12, γ2 is equal to the dA-axis, which is the true d-axis, and δ2 is equal to the qA-axis, which is the true q-axis.

In the present embodiment, as in the first embodiment, the estimated d-axis current command value Iγr, which is the output of the current command value generator 28, is set to zero, and the estimated q-axis current It is configured to output a command value Iδr. Therefore, the current I rides on the δ2 axis and on the qA axis at the same time.

As a result, when viewed from the electric motor 18, the orthogonality between the magnetic flux and the current can be maintained without being affected by the delayed phase signal .theta.1 existing in the power supply circuit 69. FIG. In this case, the magnitude of the current I (vector length) is minimized. Therefore, loss such as copper loss is minimized. As a result, a power generator that can drive the electric motor 18 with high efficiency can be realized.

That is, according to the present embodiment, two estimated phases are provided inside power supply circuit 69 . As a result, the current component on the γ2-axis, which is the estimated d-axis, becomes zero. As a result, the current I can be controlled without being affected by the phase signal θ1 having a phase delay.

Vector control by the power supply circuit 69 of this embodiment is particularly effective in the following cases.

For example, in the case of a permanent magnet embedded electric motor that can effectively use the reluctance torque, there are cases where the phase of the current I is intentionally advanced. In this case, regardless of the magnitude of the electromotive force, it is possible that the phase of the current I advances with respect to the permanent magnet, which is referred to as the current advance angle β.

At this time, a motor with a small electromotive force and a motor with a large electromotive force can be discriminated using the phase of the current I by the following method.

First, the phases of the currents I of the motors with different electromotive forces are measured and compared with respect to the permanent magnets. At this time, the motor for which a change in the current lead angle β is observed can be determined as "a motor having characteristics in which the phase of the current with respect to the permanent magnet differs when the magnitude of the electromotive force differs".

In the above-described embodiment, an example of a configuration in which three-phase to two-phase conversion and two-to-three phase conversion are frequently used has been described as an example, but the present invention is not limited to this. For configurations with two estimated phases, the conversion is from two phases (γ1, δ1) to two phases (γ2, δ2). Therefore, it may be configured with a simpler primary transform, for example, 2 rows and 2 columns. As a result, sufficient functions can be obtained with a simple conversion configuration.

As described above, according to the configurations of the first to third embodiments, the power supply circuit internally has an estimated phase different from the actual phase in the electric motor 18 . Then, the power supply circuit controls the component of the first electromotive force in the estimated phase to be a predetermined value shifted from zero. At this time, if the motor 18 stops due to step-out, the first electromotive force cannot be maintained at a predetermined value. That is, the estimated speed decreases to zero, or conversely increases. This makes it possible to detect step-out of the electric motor 18 using the estimated speed. As a result, the electric motor 18 can be properly restarted.

However, in each embodiment, it is not essential to provide the estimated phase within the power supply circuit. For example, first, a test is performed with large and small electromotive forces at the same speed. At this time, in the case of a power supply circuit having a characteristic that the current phase changes, when the electromotive force becomes almost zero due to step-out, the current phase changes in the same direction as the electromotive force becomes smaller in the test. If the change is in the lagging direction, the estimated speed will be zero. On the other hand, if the change is in the advancing direction, it is possible to cause the estimated speed to jump up at high speed.

Moreover, according to the first to third embodiments, the inverter circuit 35 is provided in the power supply circuit. Therefore, the semiconductor element of the inverter circuit 35 can be switched (ON and OFF) at a sufficiently high carrier frequency such as 15.625 kHz. As a result, power can be supplied from the inverter circuit 35 to the electric motor 18 with high efficiency. However, it is not essential to realize the switching operation by the inverter circuit. For example, it may be composed of a class A amplifier or a class B (push-pull) amplifier that operates transistors in an active state. This provides an equivalent effect with respect to the performance of detecting out-of-step.

Further, according to Embodiments 1 to 3, the electric motor 18 having a three-phase configuration has been described as an example, but the present invention is not limited to this. For example, any motor having two or more phases may be used as long as the motor has a structure in which the phase of the current I can be confirmed. Therefore, the effects of the present invention can be obtained regardless of the number of phases.

Further, according to Embodiments 1 to 3, a configuration having a power transmission path having a backlash like the coupling 61 shown in FIG. 3 has been described as an example, but the configuration is not limited to this. In the case of the power transmission path described above, even in a step-out state, a small electromotive force may be generated in the motor when the backlash moves. Furthermore, if the elastic element of the power transmission path mechanically resonates, a minute electromotive force may be generated in the electric motor as well. Therefore, in each embodiment, for example, the absolute value of the Vb value, which is the first predetermined value, is set to be larger than the minute electromotive force generated by the phenomenon described above. As a result, malfunction of the power generation device due to backlash or the like can be prevented.

Moreover, according to Embodiments 1 to 3, as described above, the out-of-step state of the electric motor is accurately detected. Then, the motor can be restarted by the restart signal output from the restart signal generator. At this time, the restart signal acts to return the power generator to a normal operating state in which work can be done. As a result, the normal operation of the power generator can be quickly restored.

In the first to third embodiments, no particular reference was made to the operation of the power generation device in response to the restart signal.

Specifically, for example, a configuration referred to as forced synchronization or synchronous operation, which supplies a fixed current and phase function regardless of the phase of the motor 18, may be used.

In addition, there is a configuration in which the phase is detected based on the difference in inductance based on the response to the high-frequency current, and the operation is performed. This case is more suitable for motors with different inductances, such as structures in which permanent magnets are embedded.

In other words, in any of the configurations described above, when the electric motor is restarted and the value of the electromotive force reaches a sufficient value, it is possible to return to the power running operation described in the above embodiment. Then, with regard to step-out that occurs thereafter, it is possible to appropriately detect and restart the system.

As described above, the power generation device of the present invention has a first body, a second body, a permanent magnet, and a winding, and the relative motion of the first body and the second body causes the winding to move. and a power supply circuit that supplies a current to the windings and has a characteristic that the phase of the current to the permanent magnet differs when the magnitude of the electromotive force differs. The power supply circuit is configured to change the frequency of the current at the time of step-out from that before step-out, and then restart the motor.

Further, the power supply circuit of the power generator of the present invention has a characteristic that the phase of the current with respect to the permanent magnet advances when the magnitude of the electromotive force is small. The motor may be restarted after the frequency of the current exceeds a predetermined value.

Further, the power supply circuit of the power generator of the present invention has a characteristic that the phase of the current to the permanent magnet is delayed when the magnitude of the electromotive force is small. The motor may be restarted after the frequency of the current becomes equal to or less than a predetermined value.

Further, the power supply circuit of the power generator of the present invention includes a speed signal generation section that outputs a speed signal, an integration section that outputs a phase signal obtained by time-integrating the speed signal, a voltage signal output section, and a current signal output section. , and a first electromotive force calculator. The voltage signal output section outputs a first phase component of the winding voltage when the phase signal is input. When the phase signal is input, the current signal output unit outputs a first phase component of the winding current and a second phase component of the winding current orthogonal to the first phase component of the winding current. Output. The first electromotive force calculation section calculates and outputs a first phase component of the electromotive force based on the outputs of the voltage signal output section and the current signal output section. Furthermore, the speed signal generator may be configured to adjust the speed signal so that the output of the first electromotive force calculator becomes the first predetermined value. As a result, it can be easily applied to a configuration in which a current is controlled by dividing it into two components on orthogonal coordinates, which is generally called vector control. As a result, the winding current can be controlled with good responsiveness.

Also, the power supply circuit of the power generator of the present invention has a winding current control section. The winding current control unit adjusts the winding current so that the first current command value and the second current command value, which are two components of orthogonal coordinates rotating in synchronization with the phase signal of the winding current, become equal. It may be configured to moderate the voltage.

According to the configuration of these power generators, it is possible to appropriately determine the out-of-step state even when the winding resistance of the electric motor is large and the speed is low. Then, when the power supply circuit detects that it is in a step-out state, it can be restarted early to restore the original function of the power generator. These can suppress the loss of electrical energy and time until functional recovery.

The power generating device of the present invention can appropriately detect a state of out-of-step, change the frequency of the current at the time of the step-out from that before the step-out, and then restart the electric motor. Therefore, it can be applied to a power generator used as a power source that requires excellent performance such as control of electric energy and time wastage.

Reference Signs List 1, 18 electric motor 2 PWM inverter 3, 4 coordinate converter 5 current controller 6 speed controller 7 magnetic flux controller 8 first speed estimator 9 integrator 10 second speed estimator 11 out-of-step determination unit 12 input active power calculation Unit 13 Axis lock determination unit 14 Axis lock detection unit 15, 16, 17 Windings 19, 69 Power supply circuit 20, 70 Winding current control unit 21 First electromotive force calculation unit 22, 76 Adder 23 First predetermined value Generating unit 24 Speed signal generating unit 25 Integrating unit 26 Speed command unit 27, 30, 31 Subtractor 28 Current command value generating unit 32, 74 Voltage signal output unit 33 Two-phase three-phase conversion unit 34, 75 Current signal output unit 35 Inverter Circuit 37 DC power supply 38, 39, 40, 41, 42, 43 switching element 44 drive circuit 45 microcomputer 45a PWM modulation unit 46 current detection unit 47, 48, 49 shunt resistor 50 amplifier 51 first object 52 second object 55 Iron core 56, 57, 58, 59 Permanent magnet 60, 62 Shaft 61 Coupling 63 Load 65, 66 Clutch 71 Current error amplifier 72 Three-phase two-phase converter 77 Phase value source

Claims (4)

an electric motor having a first object, a second object, a permanent magnet, and a winding, wherein the relative motion of the first object and the second object generates an electromotive force in the winding;
a power supply circuit that supplies a current to the winding and has a characteristic that the phase of the current to the permanent magnet differs when the magnitude of the electromotive force differs;
The power supply circuit is a power generation device configured to restart the electric motor after changing the frequency of the current at the time of step-out from that before step-out,
The power supply circuit has a characteristic that the phase of the current with respect to the permanent magnet advances when the magnitude of the electromotive force is small,
A power generating device configured to restart the electric motor after the frequency of the current in the winding exceeds a predetermined value when the speed of the electric motor is out of step. an electric motor having a first object, a second object, a permanent magnet, and a winding, wherein the relative motion of the first object and the second object generates an electromotive force in the winding;
a power supply circuit that supplies a current to the winding and has a characteristic that the phase of the current to the permanent magnet differs when the magnitude of the electromotive force differs;
The power supply circuit is a power generation device configured to restart the electric motor after changing the frequency of the current at the time of step-out from that before step-out,
The power supply circuit has a characteristic that when the magnitude of the electromotive force is small, the current phase with respect to the permanent magnet is delayed,
A power generating device configured to restart the electric motor after the frequency of the current in the winding becomes equal to or less than a predetermined value when the speed of the electric motor is zero. an electric motor having a first object, a second object, a permanent magnet, and a winding, wherein the relative motion of the first object and the second object generates an electromotive force in the winding;
a power supply circuit that supplies a current to the winding and has a characteristic that the phase of the current to the permanent magnet differs when the magnitude of the electromotive force differs;
The power supply circuit is a power generation device configured to restart the electric motor after changing the frequency of the current at the time of step-out from that before step-out,
The power supply circuit includes a speed signal generator for outputting a speed signal, an integration unit for outputting a phase signal obtained by time-integrating the speed signal, a voltage signal output unit, a current signal output unit, and a first electromotive force calculator. and
When the phase signal is input, the voltage signal output unit outputs a first phase component of the voltage of the winding,
When the phase signal is input, the current signal output section outputs a first phase component of the winding current and a first phase component of the winding current orthogonal to the first phase component of the winding current. outputs a phase component of 2,
the first electromotive force calculation unit calculates and outputs a first phase component of the electromotive force based on the outputs of the voltage signal output unit and the current signal output unit;
The speed signal generating section adjusts the speed signal so that the output of the first electromotive force calculating section becomes a first predetermined value. an electric motor having a first object, a second object, a permanent magnet, and a winding, wherein the relative motion of the first object and the second object generates an electromotive force in the winding;
a power supply circuit that supplies a current to the winding and has a characteristic that the phase of the current to the permanent magnet differs when the magnitude of the electromotive force differs;
The power supply circuit is a power generation device configured to restart the electric motor after changing the frequency of the current at the time of step-out from that before step-out,
The power supply circuit has a winding current control unit,
The winding current control unit controls the winding current so that the first current command value and the second current command value, which are two components of orthogonal coordinates rotating in synchronization with the phase signal of the winding current, are equal to each other. A power generator configured to moderate the voltage applied to the windings.

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