Controller for starting system and control method for starting system

Abstract

To provide a controller for a starting system and a control method for a starting system that can determine whether a starting control of a rotary machine using a sensorless controlled synchronous motor is appropriate.SOLUTION: The controller for a starting system includes a synchronous motor, a drive circuit, and a processing circuit. The synchronous motor is controlled by a sensorless control in which the rotation angle is not detected. The processing circuit acquires an actual current flowing through the synchronous motor, estimates an estimated induced voltage, which is an estimated value of the induced voltage of the synchronous motor, from the actual current and a voltage command value for generating a control signal input to the drive circuit, and performs an abnormality determination process to determine whether the starting of the rotary machine was successful by determining whether the estimated induced voltage is greater than or equal to a predetermined voltage reference value when starting the rotary machine.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a controller for a starting system and a method for controlling a starting system. [Background technology]

[0002] There is known a starting system that starts an engine, which is a driving source in a vehicle, ship, aircraft, etc., by a synchronous motor. It is possible to control the synchronous motor for starting such an engine by sensorless control, in which the rotation angle is not detected by a rotation angle sensor. By using sensorless control, it is possible to reduce the size of the system and the risk of failure. The following Patent Document 1 describes that in the sensorless control of a synchronous motor, an induced voltage generated in each phase of the synchronous motor is detected in order to more accurately grasp the rotation position of the magnetic poles. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-295750 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, adding a voltage sensor reduces the benefits of sensorless control, leading to an increase in the size of the system and an increased risk of failure. In addition, the increase in the number of parts also increases costs.

[0005] In particular, in a synchronous motor for starting an engine, it is difficult to estimate the magnetic pole angle of the rotor of the synchronous motor in a low rotation state when the engine is started, and control based on the magnetic pole angle may not be performed appropriately. If control based on the magnetic pole angle is not performed appropriately, the rotation speed of the synchronous motor cannot be increased, and the engine cannot be started. In addition, it is not possible to detect a state in which control based on the magnetic pole angle is not performed appropriately. Note that such problems are not limited to when an engine is started by a synchronous motor, but may also occur when a rotating machine in general is started by a synchronous motor.

[0006] The present disclosure is devised to solve the above-mentioned problems, and aims to provide a starting system controller and a starting system control method that can determine whether startup control of a rotating machine using a sensorlessly controlled synchronous motor is appropriate. [Means for solving the problem]

[0007] A controller of a starting system according to one embodiment of the present disclosure is a controller of a starting system including a synchronous motor that is mechanically connected to a rotating machine and starts the rotating machine, and a drive circuit that is electrically connected to the synchronous motor and drives the synchronous motor, and includes a processing circuit, wherein the synchronous motor is controlled by sensorless control in which detection of a rotation angle is not performed, and the processing circuit acquires an actual current flowing through the synchronous motor, estimates an estimated induced voltage, which is an estimate of the induced voltage of the synchronous motor, from the actual current and a voltage command value for generating a control signal to be input to the drive circuit, and performs an abnormality determination process to determine whether the starting of the rotating machine is successful or not by determining whether the estimated induced voltage is equal to or greater than a predetermined reference value at the start of the rotating machine.

[0008] A control method for a starting system according to another aspect of the present disclosure is a control method for a starting system including a synchronous motor that is mechanically connected to a rotating machine and starts the rotating machine, and a drive circuit that is electrically connected to the synchronous motor and drives the synchronous motor, the control method controlling the synchronous motor by sensorless control that does not detect the rotation angle, acquiring an actual current flowing through the synchronous motor, estimating an estimated induced voltage that is an estimate of the induced voltage of the synchronous motor from the actual current and a voltage command value for generating a control signal input to the drive circuit, and determining whether the estimated induced voltage is equal to or greater than a predetermined reference value at the start of the rotating machine, thereby performing an abnormality determination as to whether the starting of the rotating machine is successful. Effect of the Invention

[0009] According to the present disclosure, it is possible to determine whether or not the start-up control of a rotating machine using a sensorlessly controlled synchronous motor is appropriate. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a block diagram showing a schematic configuration of a starting system according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a diagram illustrating an example of a circuit configuration of the first power converter illustrated in FIG. [Diagram 3] FIG. 3 is a diagram showing a schematic configuration of a processing circuit in the starting system shown in FIG. [Figure 4] FIG. 4 is a flowchart showing an example of the flow of the startup abnormality determination process in this embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following, elements having the same or similar functions are denoted by the same reference numerals throughout the drawings, and duplicated descriptions thereof will be omitted.

[0012] Fig. 1 is a block diagram showing a schematic configuration of a starting system according to an embodiment of the present disclosure. As shown in Fig. 1, the starting system 1 according to the present embodiment includes an engine 2 and a synchronous motor 3. The engine 2 is configured as a driving source for a moving body such as a vehicle, a ship, or an aircraft. The engine 2 includes, for example, a gas turbine engine. Note that the engine 2 may be a reciprocating engine.

[0013] The synchronous motor 3 is mechanically connected to the engine 2. As a result, the synchronous motor 3 can rotate in synchronization with the rotation of the output shaft 4 of the engine 2. The synchronous motor 3 may be directly connected to the output shaft 4 of the engine 2, or may be connected to the output shaft 4 of the engine 2 via a power transmission mechanism such as a gear. The synchronous motor 3 is configured as a synchronous motor generator capable of generating electricity by using the driving force of the engine 2. In this embodiment, the synchronous motor 3 is controlled by sensorless control in which the rotation angle is not detected by a rotation angle sensor. The synchronous motor 3 has a cylindrical rotor to accommodate the high-speed rotation of the engine 2. That is, the synchronous motor 3 in this embodiment is a cylindrical synchronous motor in which magnets are arranged on the surface of the rotor. However, the synchronous motor 3 is not limited to this, and may have, for example, a salient pole rotor.

[0014] Furthermore, the starting system 1 includes a first power converter 5 electrically connected to the synchronous motor 3. The first power converter 5 is configured as a drive circuit that drives the synchronous motor 3. The first power converter 5 and the synchronous motor 3 are connected by an AC wiring 6. The first power converter 5 is connected to a predetermined power source 8 via a second power converter 7. The first power converter 5 and the second power converter 7 are connected by a DC wiring 9. A capacitor 10 that defines a DC voltage in the DC wiring 9 is electrically connected to the DC wiring 9. The first power converter 5 converts the AC power generated by the synchronous motor 3 into DC power and supplies it to the DC wiring 9, and converts the DC power in the DC wiring 9 into AC power and supplies it to the synchronous motor 3.

[0015] The power source 8 may be, for example, an AC power source system such as an AC system in a vehicle, or may be, for example, a DC power source system such as a battery. That is, the power source wiring 11 between the second power converter 7 and the power source 8 is AC wiring when the power source 8 is an AC power source system, and is DC wiring when the power source 8 is a DC power source system. The second power converter 7 converts the DC power of the DC wiring 9 into power to be supplied to the power source 8, and converts the power source power from the power source 8 into DC power to be supplied to the DC wiring 9. The second power converter 7 is an AC-DC converter when the power source 8 is an AC power source system, and is a DC-DC converter when the power source 8 is a DC power source system.

[0016] Furthermore, the starting system 1 includes a controller 12. The controller 12 controls the first power converter 5 and the second power converter 7. The controller 12 includes a processing circuit 13 that performs various signal processing. The processing circuit 13 includes a computer such as a microcontroller, a personal computer, or a PLC (Programmable Logic Controller). For example, the processing circuit 13 includes a processor, a memory, and peripheral circuits. Moreover, the processing circuit 13 of the controller 12 may be configured by a plurality of divided processing circuits.

[0017] The processor includes, for example, a CPU or an MPU. The memory includes volatile memory such as a ROM, a RAM, and a register, and non-volatile memory such as a flash memory. The memory stores a control program for the power converters 5, 7 in advance. The memory includes peripheral circuits, an input / output interface, and the like. The processor, memory, and peripheral circuits transmit data to each other via a bus. The processor executes the control program to perform arithmetic processing (described later) based on various information stored in the memory.

[0018] It should be noted that the functions of the elements disclosed herein can be performed using circuits or processing circuits including general purpose processors, special purpose processors, integrated circuits, ASICs (Application Specific Integrated Circuits), conventional circuits, or combinations thereof configured or programmed to perform the disclosed functions. A processor is considered a processing circuit or circuit because it includes transistors and other circuits. In this specification, a circuit, unit, or means is hardware that performs the recited functions or hardware that is programmed to perform the recited functions. The hardware may be hardware disclosed in this specification or other known hardware that is programmed or configured to perform the recited functions. In the case where the hardware is a processor that is considered a type of circuit, the circuit, unit, means, or part is a combination of hardware and software, and the software is used to configure the hardware or processor.

[0019] FIG. 2 is a diagram showing an example of a circuit configuration of the first power converter shown in FIG. 1. In the example of FIG. 2, the first power converter 5 is configured as a PWM (Pulse Width Modulation) inverter circuit. In this case, the first power converter 5 is realized by, for example, a three-phase bridge circuit. The first power converter 5 converts DC power provided by a DC wiring 9 into three-phase AC power and supplies it to the synchronous motor 3. That is, the AC wiring 6 includes three connection wirings 6a, 6b, and 6c. The connection wirings 6a, 6b, and 6c are connected to three terminals 3a, 3b, and 3c of the synchronous motor 3, respectively. The windings of the stator connected to the three terminals 3a, 3b, and 3c, respectively, correspond to the a-phase winding, the b-phase winding, and the c-phase winding.

[0020] The first power converter 5 includes a plurality of switching elements T for passing AC current through each of the connection wirings 6a and 6c. The switching elements T are switched between on and off states based on a drive signal Sd1 from the controller 12. In the switching elements T, the on state means a conductive state between the main terminals of the switching elements T, and the off state means a cut-off state between the main terminals of the switching elements T. The switching elements T are realized by, for example, transistors. For example, in the example of FIG. 2, the switching elements T are IGBTs or bipolar transistors. In this case, a diode D is connected in inverse parallel to the switching elements T. The switching elements T may be field-effect transistors such as MOSFETs. In this case, the diode D does not need to be connected to the switching elements.

[0021] In this embodiment, the switching element T includes six switching elements T1U, T1D, T2U, T2D, T3U, and T3D. The switching elements T1U and T1D are connected in series to form a switching element pair, and the switching element pair is connected in parallel to the capacitor 10. Similarly, the switching elements T2U and T2D are connected in series to form a switching element pair, and the switching element pair is connected in parallel to the capacitor 10. Similarly, the switching elements T3U and T3D are connected in series to form a switching element pair, and the switching element pair is connected in parallel to the capacitor 10.

[0022] A connection wire 6a is connected to an intermediate wire 51 between the switching elements T1U and T1D. A connection wire 6b is connected to an intermediate wire 52 between the switching elements T2U and T2D. A connection wire 6c is connected to an intermediate wire 53 between the switching elements T3U and T3D.

[0023] The processing circuit 13 of the controller 12 generates a gate signal corresponding to each switching element T. The gate signal is a PWM modulated, i.e., pulse width modulated, signal. A combination of the gate signals for the multiple switching elements T becomes the drive signal Sd1.

[0024] The processing circuit 13 is capable of executing a power generation control mode in which the synchronous motor 3 functions as a generator, and a start control mode in which the synchronous motor 3 functions as a starter for the engine 2.

[0025] In the power generation control mode, the processing circuit 13 controls the first power converter 5 to convert the AC power in the AC wiring 6 between the synchronous motor 3 and the first power converter 5 into DC power and output it to the DC wiring 9. In the power generation control mode, the processing circuit 13 estimates the angular speed and phase of the magnetic poles of the rotor of the synchronous motor 3 from the actual current flowing through the synchronous motor 3 and a target voltage value in the AC wiring 6. The processing circuit 13 generates a drive signal Sd1 for controlling the first power converter 5, which functions as a rectifier, to follow the estimated angular speed and phase.

[0026] In the start control mode, the processing circuit 13 converts the DC power of the DC wiring 9 into AC power and controls the first power converter 5 to supply the AC power to the synchronous motor 3 in order to start the engine 2 from a stopped state. In the start control mode, the processing circuit 13 generates a drive signal Sd1 for controlling the first power converter 5 so that AC currents having a sine waveform with a phase difference of 120 degrees flow through the connection wirings 6a, 6b, and 6c. The rotor of the synchronous motor 3 is driven to rotate by such AC currents flowing through the connection wirings 6a, 6b, and 6c. The processing circuit 13 can change the speed of the rotor of the synchronous motor 3 by adjusting the drive signal Sd1.

[0027] In this embodiment, the processing circuit 13 executes a first control, which is a sensorless vector control, when the angular velocity of the synchronous motor 3 is equal to or greater than a predetermined reference angular velocity, and executes a second control different from the first control while the angular velocity of the synchronous motor 3 is less than a first angular velocity reference value ωa from the start of the synchronous motor 3. For example, the first angular velocity reference value ωa can be set to an angular velocity corresponding to a rotation speed at which the engine 2 can operate autonomously.

[0028] For example, the second control may be V / f control using a current target value. In this case, the processing circuit 13 generates the current target value using a preset value or an arithmetic expression. The processing circuit 13 generates a voltage target value using, for example, a PID calculation so that the actual current matches the current target value. The processing circuit 13 generates a voltage target value such that the ratio of the output voltage to the frequency of the first power converter 5 is constant.

[0029] The starting system 1 includes a current detector 15 that detects an AC current in the AC wiring 6 in order to control the first power converter 5 by the first control using the processing circuit 13 of the controller 12. The current detector 15 includes a first detector 15a that detects a current Ia in the connecting wiring 6a and a second detector 15c that detects a current Ic in the connecting wiring 6c. The current Ib in the connecting wiring 6b can be calculated from the vector sum of the current Ia in the connecting wiring 6a and the current Ic in the connecting wiring 6c.

[0030] Fig. 3 is a diagram showing a schematic configuration of a processing circuit in the starting system shown in Fig. 1. The processing circuit 13 includes an estimation unit 21 and a signal generation unit 22 as control blocks. The estimation unit 21 estimates the angular velocity and phase of the magnetic poles in the rotor of the synchronous motor 3. To this end, the estimation unit 21 has a dq conversion circuit 23, a model application circuit 24, and an estimation circuit 25.

[0031] The dq conversion circuit 23 outputs a d-axis actual current Id and a q-axis actual current Iq from the instantaneous value of the current flowing through the AC wiring 6 detected by the current detectors 15a and 15c, using an estimated magnetic pole phase θm, which will be described later. The model application circuit 24 estimates the current flowing through the synchronous motor 3, using a model calculation formula that models the synchronous motor 3. The model calculation formula is stored in advance in the memory of the processing circuit 13.

[0032] The d-axis actual current Id and the q-axis actual current Iq are input to the model application circuit 24. Furthermore, the d-axis voltage target value Vod and the q-axis voltage target value Voq generated by a voltage target value generation circuit 26 described later are input to the model application circuit 24. Furthermore, the estimated induced voltage Em estimated by an estimation circuit 25 is input to the model application circuit 24. The model application circuit 24 outputs the d-axis estimated current Imd and the q-axis estimated current Imq by substituting these values ​​Id, Iq, Vod, Voq, and Em into the model computational equation and solving the model computational equation.

[0033] The estimation circuit 25 estimates the estimated induced voltage Em, the estimated angular velocity ωm, and the estimated phase θm from the d-axis estimated deviation ΔId between the d-axis actual current Id and the d-axis estimated current Imd and the q-axis estimated deviation ΔIq between the q-axis actual current Iq and the q-axis estimated current Imq using a predetermined estimation algorithm. The d-axis estimated deviation ΔId is obtained by subtracting the d-axis estimated current Imd from the d-axis actual current Id. The q-axis estimated deviation ΔIq is obtained by subtracting the q-axis estimated current Imq from the q-axis actual current Iq.

[0034] As described above, the estimated induced voltage Em estimated by the estimation circuit 25 is substituted into the model calculation formula in the model application circuit 24. The estimated phase θm is used in the dq conversion circuit 23 and a drive signal generation circuit 27, which will be described later.

[0035] The signal generating unit 22 generates a drive signal Sd1 for the first power converter 5. To this end, the signal generating unit 22 has a voltage target value generating circuit 26 and a drive signal generating circuit 27. The voltage target value generating circuit 26 generates voltage target values ​​Vod, Voq using the d-axis actual current Id, the q-axis actual current Iq, and the estimated angular velocity ωm estimated by the estimation circuit 25.

[0036] For example, the voltage target value generation circuit 26 generates an angular velocity deviation Δω, which is the deviation between the estimated angular velocity ωm and the angular velocity target value ωo. The angular velocity deviation Δω is obtained by subtracting the estimated angular velocity ωm from the angular velocity target value ωo. The voltage target value generation circuit 26 performs PID calculation on the angular velocity deviation Δω to calculate the q-axis current target value Ioq. The d-axis current target value Iod is set according to the torque target value or the rotation speed target value, etc.

[0037] The voltage target value generating circuit 26 generates a d-axis target deviation ΔIod between the d-axis current target value Iod and the d-axis actual current Id, and a q-axis target deviation ΔIoq between the q-axis current target value Ioq and the q-axis actual current Iq. The d-axis target deviation ΔIod is obtained by subtracting the d-axis actual current Id from the d-axis current target value Iod. The q-axis target deviation ΔIoq is obtained by subtracting the q-axis actual current Iq from the q-axis current target value Ioq. The voltage target value generating circuit 26 performs PID calculations on the d-axis target deviation ΔIod to calculate the d-axis voltage target value Vod, and performs PID calculations on the q-axis target deviation ΔIoq to calculate the q-axis voltage target value Voq.

[0038] The drive signal generation circuit 27 generates a drive signal Sd1 from the voltage target values ​​Vod, Voq and the estimated phase θm. The drive signal generation circuit 27 performs an inverse dq transformation on the voltage target values ​​Vod, Voq using the estimated magnetic pole phase θm to calculate three-phase voltage target values ​​voa, vob, and voc. Furthermore, the drive signal generation circuit 27 generates a drive signal Sd1 by pulse-width modulating the three-phase voltage target values ​​voa, vob, and voc based on a predetermined carrier frequency fc.

[0039] At the beginning of starting the engine 2, the induced voltage in the synchronous motor 3 is zero or very small, making it difficult to estimate the angular velocity ω and phase θ of the synchronous motor 3. For this reason, the engine 2 is started by the second control instead of the first control. At the start of the engine 2, the processing circuit 13 gradually increases the frequency target value or the current target value. Accordingly, the rotation speed of the engine 2 increases together with the synchronous motor 3. As a result, the synchronous motor 3 is controlled without estimating the angular velocity and induced voltage of the synchronous motor 3.

[0040] However, in such a second control, the angular velocity ω and phase θ of the synchronous motor 3 are not estimated, and therefore, it is not possible to correctly detect whether the synchronous motor 3 is rotating normally by only the feedback in the second control. In particular, when the synchronous motor 3 has a cylindrical rotor, it is more difficult to estimate the rotation angle of the rotor when the rotation stops. Therefore, the processing circuit 13 performs an abnormality determination process to determine whether the engine 2 has been successfully started by determining whether the estimated induced voltage Em is equal to or greater than a predetermined voltage reference value Ec when the engine 2 is started.

[0041] FIG. 4 is a flowchart showing an example of the flow of the start-up abnormality determination process in this embodiment. The processing circuit 13 determines whether or not the estimated angular velocity ωm is less than the second angular velocity reference value ωc (step S1). The second angular velocity reference value ωc may be the same value as the first angular velocity reference value ωa that is the reference for switching from the first control to the second control, or may be a different value. The second angular velocity reference value ωc may be set as a value of the angular velocity of the synchronous motor 3 corresponding to the rotation speed of the engine 2 at which the start of the engine 2 is considered to be successful. Note that, instead of using the estimated angular velocity ωm to make the determination, a similar determination may be made using the frequency of the AC power output by the first power converter 5 to the AC wiring 6. If the estimated angular velocity ωm is less than the second angular velocity reference value ωc (Yes in step S1), the processing circuit 13 determines whether or not the estimated induced voltage Em is less than the voltage reference value Ec (step S2).

[0042] The induced voltage of the synchronous motor 3 is proportional to the rotation speed of the synchronous motor 3. Therefore, the voltage reference value Ec is set based on the rotation speed that the synchronous motor 3 should reach in the second control. For example, when the induced voltage target value corresponding to the rotation speed that the synchronous motor 3 should reach in the second control is Eo, the voltage reference value Ec is set to a value obtained by subtracting the allowable error α from the induced voltage target value Eo, that is, Ec=Eo-α. The allowable error α may be 0, in which case the voltage reference value Ec coincides with the induced voltage target value Eo.

[0043] If the estimated induced voltage Em is less than the voltage reference value Ec (Yes in step S2), the processing circuit 13 adds a predetermined number n to the counter value C (step S3). The initial value of the counter value is 0. On the other hand, if the estimated induced voltage Em is equal to or greater than the voltage reference value Ec (No in step S2), the processing circuit 13 subtracts a predetermined number m from the counter value C (step S4). However, the lower limit of the counter value C is 0. For example, when the processing circuit 13 determines that the estimated induced voltage Em is equal to or greater than the voltage reference value Ec while the counter value C is 0, it maintains the counter value C at 0. The predetermined numbers n and m may be the same number or different numbers. For example, the predetermined number n=m=1 may be used.

[0044] When the counter value C is increased by step S3, the processing circuit 13 determines whether the counter value C exceeds a predetermined threshold value Cth (step S5). When the counter value C exceeds the predetermined threshold value Cth (Yes in step S5), the processing circuit 13 determines that the start of the engine 2 has not been successful, and performs abnormality processing (step S6).

[0045] On the other hand, if the counter value C has decreased in step S4 or if the counter value C is equal to or less than the predetermined threshold value Cth (No in step S5), the processing circuit 13 repeats the processing from step S1 to step S5 for every predetermined unit time. If the estimated angular velocity ωm becomes equal to or greater than the second angular velocity reference value ωc in step S1 (No in step S1), the processing circuit 13 determines that the engine 2 has been successfully started, and resets the counter value C to 0 (step S7). After that, the processing circuit 13 ends the abnormality determination processing.

[0046] As described above, according to the present embodiment, an abnormality determination process is performed to determine whether or not the engine 2 has been successfully started, based on the estimated induced voltage Em estimated from the actual current flowing through the synchronous motor 3. Since the induced voltage is proportional to the rotation speed of the synchronous motor 3, the estimated induced voltage can be used to determine whether or not the engine 2 has been started, instead of detecting the rotation speed. Therefore, it can be determined whether or not the engine 2 has been properly started, without separately measuring the voltage, rotation speed, etc. of the synchronous motor 3. In particular, by performing such an abnormality determination process during the execution of the second control before the start of the first control, which is the sensorless vector control, it is possible to prevent a transition to the first control without detecting that the engine 2 has not been successfully started.

[0047] Furthermore, according to this embodiment, the estimated induced voltage Em is compared with the voltage reference value Ec multiple times per unit time, and if the number of times that the estimated induced voltage Em is less than the voltage reference value Ec before the estimated angular velocity ωm becomes the second angular velocity reference value ωc exceeds a threshold value Cth, it is determined that starting of the engine 2 has not been successful.

[0048] As described above, since it is difficult to estimate the induced voltage at low revolutions, the estimated induced voltage Em may contain a relatively large error, and the estimated induced voltage Em may fluctuate up and down. In particular, if the engine 2 is not successfully started, the estimated induced voltage Em is expected to fluctuate greatly. In addition, the induced voltage may increase with a delay relative to the increase in the actual rotation speed of the synchronous motor 3. In addition, if the second angular velocity reference value ωc is larger than the first angular velocity reference value ωa, the second control, such as the V / f control mode, is switched to the first control, which is the sensorless vector control mode, during the execution period of the abnormality determination process. There is a risk that the estimated induced voltage Em may become discontinuous when the control mode is switched.

[0049] Therefore, when the estimated induced voltage Em is determined to be less than the voltage reference value Ec multiple times, it is determined that starting of the engine 2 has not been successful, thereby reducing the possibility of erroneous determination. On the other hand, when the estimated induced voltage Em is equal to or greater than the voltage reference value Ec, by subtracting the count value C, it is possible to suppress erroneous determination that an abnormality has occurred even when starting of the engine 2 has been successful, for example, when the induced voltage rises later than expected.

[0050] As described above, the estimated induced voltage Em used in the abnormality determination process is expected to have a large error and fluctuation. Therefore, the processing circuit 13 may perform a filter process on the estimated induced voltage Em before comparing the estimated induced voltage Em with the voltage reference value Ec. For example, the filter applied to the estimated induced voltage Em may include a first-order lag filter or the like.

[0051] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various improvements, changes, and modifications are possible without departing from the spirit and scope of the present disclosure.

[0052] [Other embodiments] For example, in the above embodiment, an example has been shown in which the voltage reference value Ec to be compared with the estimated induced voltage Em is set to a fixed value, but instead, the processing circuit 13 may increase the voltage reference value Ec in accordance with the elapsed time from the start of the engine 2. In this case, the counter value C may not be used. That is, the processing circuit 13 may determine that the start of the engine 2 has not been successful when the estimated induced voltage Em is less than the voltage reference value Ec that increases in accordance with the elapsed time.

[0053] The voltage reference value Ec can be determined in advance from experimental values, design values, or the like, based on the change over time in the angular velocity ω of the synchronous motor 3 when the second control is performed.

[0054] Moreover, when the voltage reference value Ec is increased according to the passage of time, an upper limit value determined based on the voltage reference value Ec may be set. That is, the processing circuit 13 may determine whether or not the estimated induced voltage Em is outside the voltage reference value range at every predetermined unit time from the start of the synchronous motor 3. As described above, if the start of the engine 2 is not successful, the fluctuation of the estimated induced voltage Em is expected to be large. Therefore, even if the estimated induced voltage Em is larger than expected, the rotation of the synchronous motor 3 may be poor. Therefore, the start determination of the engine 2 can be performed based on the magnitude of the amplitude of the estimated induced voltage Em. The determination based on the magnitude of the amplitude of the estimated induced voltage Em may be used in combination with the determination using the counter value C.

[0055] In the above embodiment, the synchronous motor 3 is a synchronous motor generator capable of generating electricity using the rotational power of the engine 2, but the synchronous motor 3 does not have to function as a generator.

[0056] In the above embodiment, the engine 2 is exemplified as an object to be started by the power of the synchronous motor 3, but the present invention is not limited to this and can be applied to the case of starting other rotating machines. For example, other rotating machines may include various blowers such as an aeration blower, various fans, various pumps, etc.

[0057] [Summary of this disclosure] [Item 1] A controller of a starting system according to one embodiment of the present disclosure is a controller of a starting system including a synchronous motor that is mechanically connected to a rotating machine and starts the rotating machine, and a drive circuit that is electrically connected to the synchronous motor and drives the synchronous motor, and includes a processing circuit, wherein the synchronous motor is controlled by sensorless control in which detection of a rotation angle is not performed, and the processing circuit acquires an actual current flowing through the synchronous motor, estimates an estimated induced voltage, which is an estimate of the induced voltage of the synchronous motor, from the actual current and a voltage command value for generating a control signal to be input to the drive circuit, and performs an abnormality determination process to determine whether the starting of the rotating machine is successful or not by determining whether the estimated induced voltage is equal to or greater than a predetermined reference value at the start of the rotating machine.

[0058] According to the above configuration, an abnormality determination process is performed to determine whether the rotating machine has been successfully started based on the estimated induced voltage estimated from the actual current flowing through the synchronous motor. Since the induced voltage is proportional to the rotation speed of the synchronous motor, the estimated induced voltage can be used to determine whether the rotating machine has been started up successfully, instead of detecting the rotation speed. Therefore, it is possible to determine whether the rotating machine has been properly started up without separately measuring the voltage, rotation speed, etc. of the synchronous motor.

[0059] [Item 2] In the controller of the starting system of item 1, the processing circuit may determine whether the estimated induced voltage is equal to or greater than the voltage reference value at each predetermined unit time from the start of starting the synchronous motor, increment a count value when the estimated induced voltage is less than the voltage reference value, and determine that an abnormality has occurred when the count value exceeds a predetermined threshold value. If the estimated induced voltage is determined to be less than the reference value multiple times, it is determined that the starting of the rotating machine has not been successful, thereby reducing the possibility of erroneous determination.

[0060] [Item 3] In the controller of the starting system of item 2, the processing circuit may subtract the count value when the estimated induced voltage is equal to or greater than the voltage reference value. This makes it possible to suppress erroneous determination that an abnormality has occurred even when the rotating machine has been successfully started, for example, when the induced voltage rises later than expected.

[0061] [Item 4] In the controller of the starting system of any of items 1 to 3, the processing circuit may determine whether or not the estimated induced voltage is outside a reference value range based on the voltage reference value at each predetermined unit time from the start of startup of the synchronous motor, increase the voltage reference value range in accordance with the elapsed time from the startup of the rotating machine, and determine that the starting of the rotating machine has not been successful if the estimated induced voltage is outside the voltage reference value range.

[0062] [Item 5] In the controller of the starting system of any of items 1 to 4, the processing circuit may execute a first control which is a sensorless vector control when the angular speed of the synchronous motor is equal to or greater than a predetermined reference angular speed, and execute a second control different from the first control while the angular speed of the synchronous motor is less than the reference angular speed from the start of startup of the synchronous motor, and perform the abnormality determination process while the second control is being executed.

[0063] [Item 6] In the controller of the starting system according to any one of items 1 to 5, the synchronous motor may be a cylindrical synchronous motor having magnets arranged on a surface of a rotor.

[0064] [Item 7] In the controller of the starting system of any one of items 1 to 6, the rotating machine may be an engine.

[0065] [Item 8] A control method for a starting system according to another aspect of the present disclosure is a control method for a starting system including a synchronous motor that is mechanically connected to a rotating machine and starts the rotating machine, and a drive circuit that is electrically connected to the synchronous motor and drives the synchronous motor, the control method controlling the synchronous motor by sensorless control that does not detect the rotation angle, acquiring an actual current flowing through the synchronous motor, estimating an estimated induced voltage that is an estimate of the induced voltage of the synchronous motor from the actual current and a voltage command value for generating a control signal input to the drive circuit, and determining whether the estimated induced voltage is equal to or greater than a predetermined reference value at the start of the rotating machine, thereby performing an abnormality determination as to whether the starting of the rotating machine is successful. [Explanation of symbols]

[0066] 1 Starting System 2. Engines (rotating machines) 3 Synchronous motor 5. First power converter (drive circuit) 12 Controller 13 Processing circuit

Claims

1. A controller for a starting system including a synchronous motor that is mechanically connected to a rotating machine and starts the rotating machine, and a drive circuit that is electrically connected to the synchronous motor and drives the synchronous motor, A processing circuit is provided, The synchronous motor is controlled by a sensorless control in which a rotation angle is not detected, The processing circuitry includes: Acquiring an actual current flowing through the synchronous motor; estimating an estimated induced voltage, which is an estimated value of an induced voltage of the synchronous motor, from the actual current and a voltage command value for generating a control signal input to the drive circuit; A controller for a starting system that performs an abnormality determination process to determine whether or not the starting of the rotating machine has been successful by determining whether or not the estimated induced voltage is equal to or greater than a predetermined voltage reference value when the rotating machine is started.

2. The processing circuitry includes: determining whether or not the estimated induced voltage is equal to or greater than the voltage reference value at each predetermined unit time from the start of the startup of the synchronous motor; When the estimated induced voltage is less than the voltage reference value, a count value is incremented; 2. The controller of claim 1, wherein the controller determines that an abnormality exists when the count value exceeds a predetermined threshold value.

3. The controller of claim 2 , wherein the processing circuit decrements the count value when the estimated induced voltage is equal to or greater than the voltage reference value.

4. The processing circuitry includes: determining whether or not the estimated induced voltage is less than the voltage reference value at each predetermined unit time from the start of a startup of the synchronous motor; increasing the voltage reference value in accordance with the elapsed time from the start of the rotating machine; The controller of claim 1 , further comprising: a controller configured to determine that starting of the rotating machine is not successful when the estimated induced voltage is less than the voltage reference value.

5. The processing circuitry includes: When the angular velocity of the synchronous motor is equal to or greater than a predetermined reference angular velocity, a first control which is a sensorless vector control is executed, and during a period from the start of the start of the synchronous motor until the angular velocity of the synchronous motor is less than the reference angular velocity, a second control different from the first control is executed; The controller for a starting system according to claim 1 , wherein the abnormality determination process is performed while the second control is being executed.

6. 5. The controller for a starting system according to claim 1, wherein the synchronous motor is a cylindrical synchronous motor having magnets arranged on a surface of a rotor.

7. 5. The controller of claim 1, wherein the rotating machine is an engine.

8. A control method for a starting system including a synchronous motor that is mechanically connected to a rotating machine and starts the rotating machine, and a drive circuit that is electrically connected to the synchronous motor and drives the synchronous motor, comprising: The synchronous motor is controlled by a sensorless control that does not detect a rotation angle, Acquiring an actual current flowing through the synchronous motor; estimating an estimated induced voltage, which is an estimated value of an induced voltage of the synchronous motor, from the actual current and a voltage command value for generating a control signal input to the drive circuit; A control method for a starting system, comprising: determining whether the estimated induced voltage is equal to or greater than a predetermined voltage reference value when the rotating machine is started, thereby determining whether the rotating machine has been successfully started or not.

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