Starting control method for power generation system and starting control device for power generation system

Abstract

The starting control method of the power generation system of the present invention, when starting a power generation system including an internal combustion engine as a power source, a generator, and a power transmission mechanism that transmits power between the internal combustion engine and the generator, drives the generator using the power supplied from a storage battery, and performs a rotational speed control to make the rotational speed of the generator coincide with a target rotational speed. In this starting control method of the power generation system, the outputtable power of the storage battery is acquired, and the rotational speed of the generator is acquired. In addition, a filtering process is performed on the rotational speed of the generator to reduce components in the resonance frequency band of the spring mass system composed of the internal combustion engine, the generator, and the power transmission mechanism. Furthermore, based on the filtered rotational speed and the outputtable power, an upper limit value of the torque for the generator, that is, an upper limit torque, is calculated. Moreover, the rotational speed control is performed under the limitation based on this upper limit torque.

Description

Technical Field

[0001] The present invention relates to a starting control method and a starting control device for a power generation system. Background Art

[0002] Japanese Patent Application Publication No. JP2021-124058A discloses an engine starting control device that rotates an engine (internal combustion engine) mounted on a vehicle as a power source using an electric motor capable of controlling the rotational speed.

[0003] In recent years, some vehicles are equipped with a power generation system including an engine as a power source, a generator, and a power transmission mechanism that transmits power between the engine and the generator. When starting the power generation system mounted on a vehicle, sometimes the generator is driven by the power supplied from the battery to idle the engine (so-called electric drive). For example, in a so-called series hybrid vehicle, generally, after the engine speed is increased to a preset specified speed by electric drive, the engine is ignited and power generation control is started. Since the speed of the generator and the like causes the power generation system to oscillate in the resonance frequency band of the power generation system, in order to reduce such oscillation, as described above, a starting method is adopted in which the speed is rapidly increased to a speed higher than the resonance frequency band by electric drive.

[0004] However, when starting the power generation system, when the power that the battery can output is insufficient for driving the generator, the engine speed cannot be rapidly increased to the speed necessary for starting power generation by electric drive. In this case, there is a problem that the time during which the speed of the generator and the like stays in the resonance frequency band becomes longer and the oscillation of the power generation system cannot be reduced. Moreover, in the case of performing electric drive during starting by speed control that makes the generator speed coincide with the target speed, the speed variation of the generator and the like is promoted, and it is easy for the time staying in the resonance frequency band to become particularly long. Summary of the Invention

[0005] An object of the present invention is to provide a starting control method and a starting control device for a power generation system that can rapidly increase the speed (rotational speed) of a generator and the like to a speed exceeding the resonance frequency band by electric drive even when the power that the battery can output is small when starting the power generation system.

[0006] One aspect of the present invention is a method for starting control of a power generation system. When starting a power generation system including an internal combustion engine as a power source, a generator, and a power transmission mechanism that transmits power between the internal combustion engine and the generator, the generator is driven by power supplied from a storage battery, and a rotation speed control for making the rotation speed of the generator coincide with a target rotation speed is performed. In this starting method of the power generation system, the outputtable power of the storage battery is acquired, and the rotation speed of the generator is acquired. In addition, a filtering process for reducing components in the resonance frequency band of a spring mass system composed of the internal combustion engine, the generator, and the power transmission mechanism is performed on the rotation speed of the generator. Further, an upper limit torque, which is the upper limit value of the torque for the generator, is calculated based on the filtered rotation speed of the generator and the outputtable power of the storage battery. Moreover, the rotation speed control is performed under the limitation based on this upper limit torque. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 FIG. is a block diagram showing the structure of a vehicle equipped with a power generation system.

[0008] Figure 2 FIG. is an explanatory diagram showing a starting mode of the power generation system corresponding to the temperature of the engine and the outputtable power of the storage battery.

[0009] Figure 3 FIG. is an explanatory diagram showing the change in the rotation speed of the generator and the ignition timing of the engine in the first extremely low temperature starting mode.

[0010] Figure 4 FIG. is an explanatory diagram showing the relationship among the SOC, temperature, and outputtable power of the storage battery.

[0011] Figure 5 FIG. is a graph showing the relationship between the engine oil temperature and the absolute viscosity of the engine oil.

[0012] Figure 6 FIG. is an explanatory diagram showing the change in the rotation speed of the generator, the ignition timing of the engine, and the change in the generator torque in the second extremely low temperature starting mode.

[0013] Figure 7 FIG. is an explanatory diagram showing the engine torque and the generator torque in the case of performing rotation speed control in the second extremely low temperature starting mode.

[0014] Figure 8 FIG. is a flowchart regarding the selection of the starting mode.

[0015] Figure 9 FIG. is a flowchart of the rotation speed control based on the second extremely low temperature starting mode.

[0016] Figure 10It is a graph showing a comparison example of torque and rotational speed in the case where starting control of a second cryogenic starting mode is performed using the upper limit torque without filtering processing in a cryogenic environment.

[0017] Figure 11 It is a graph showing an example of torque and rotational speed in the case where a power generation system is started by a second cryogenic starting mode in a cryogenic environment.

[0018] Figure 12 It is a graph showing the outputtable power of a storage battery and the actual power consumption of a generator.

[0019] Figure 13 It is an explanatory diagram showing the function of a margin set for the outputtable power of a storage battery. Detailed implementation mode

[0020] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0021] Figure 1 It is a block diagram showing the structure of a vehicle 100 equipped with a power generation system 10. As Figure 1 shown, the vehicle 100 of the present embodiment is a series hybrid vehicle including a power generation system 10, a storage battery 11, a motor 12, and a vehicle controller 13 that controls them together. That is, the vehicle 100 charges the storage battery 11 with the power generated by the power generation system 10. Then, the vehicle 100 travels by driving the drive motor 12 using the power of the storage battery 11. However, the present invention can also be applied to other types of hybrid vehicles as long as they are vehicles equipped with the power generation system 10. In addition, it can also be applied to power generation systems other than the power generation system 10 mounted on the vehicle 100.

[0022] The power generation system 10 includes: an engine 14, a generator 15, and a power transmission mechanism 16.

[0023] The engine 14 is a so-called internal combustion engine and is the power source of the power generation system 10. The rotational speed of the engine 14 (hereinafter referred to as the engine rotational speed N E) , the torque (hereinafter referred to as the engine torque T E ), and various parameters indicating the operating state of the engine 14 such as the temperature of the engine 14 are appropriately detected or obtained through sensors or calculations (not shown). In the present embodiment, the temperature of the engine oil (hereinafter referred to as the engine oil temperature T oil ) is obtained as the temperature of the engine 14.

[0024] When the power generation system 10 generates power, the engine 14 is controlled so that the engine torque T Ematches the target values corresponding to the power generation amount, power generation efficiency, etc. (hereinafter referred to as the engine torque target value T E *). In this way, the control for making the torque match the target torque is called torque control. The torque control of the engine 14 is achieved, for example, by feedback control such as PI control (Proportional-Integral Control) based on the actual engine torque T E and the engine torque target value T E *.

[0025] In addition, according to the actual structure of the vehicle 100, the engine 14 can sometimes input power not to the generator 15 but to the drive motor 12 and become the power source for driving the vehicle 100. In the present embodiment, for simplicity, it is assumed that the engine 14 is only driven when power generation is necessary and its power is input to the generator 15.

[0026] The generator 15 generates electricity using the power output by the engine 14 and charges the generated electricity to the storage battery 11. In addition, when starting the power generation system 10, the generator 15 is driven using the power of the storage battery 11 to make the engine 14 idle (hereinafter referred to as electric drive). Various parameters indicating the operating state of the generator 15, such as the rotational speed of the generator 15 (hereinafter referred to as the generator rotational speed N G ) and the torque (hereinafter referred to as the generator torque T G ), can be appropriately detected or obtained through sensors (not shown) or calculations.

[0027] At least when the power generation system 10 is generating electricity, the generator 15 is controlled so that the generator rotational speed N G matches the target values corresponding to the power generation amount, power generation efficiency, etc. (hereinafter simply referred to as the target rotational speed N G *). Therefore, during power generation, the engine rotational speed N E is determined by the generator rotational speed N G . As described above, the control for making the rotational speed match the target rotational speed is called rotational speed control. In the present embodiment, especially when starting the power generation system 10, the generator 15 is also controlled by rotational speed control. The rotational speed control of the generator 15 is achieved, for example, by feedback control such as PI control based on the actual generator rotational speed N G and the target rotational speed N G *.

[0028] The power transmission mechanism 16 is a mechanical mechanism that connects the engine 14 and the generator 15, and transmits power between the engine 14 and the generator 15. The power transmission mechanism 16 is constituted by, for example, a damper, a speed reducer, a transmission, or a combination thereof. In any case, the power transmission mechanism 16 functions as a spring element or a damping element related to power transmission, or as both a spring element and a damping element. Therefore, the engine 14, the generator 15, and the power transmission mechanism 16 (i.e., the power generation system 10) constitute a so-called spring-mass system and have an inherent resonance frequency ω corresponding to its specific structure. p (not shown). Therefore, when the engine speed N E or the generator speed N G stays in this resonance frequency ω p or a frequency band near it (hereinafter referred to as the resonance frequency band B RF ), large vibrations may sometimes occur in the power generation system 10. In addition, hereinafter, the resonance frequency ω p and the resonance frequency band B RF of the spring-mass system constituted by the engine 14, the generator 15, and the power transmission mechanism 16 are respectively referred to as the resonance frequency ω p of the power generation system 10 and the resonance frequency band B RF of the power generation system 10.

[0029] The storage battery 11 is a secondary battery and can be recharged. The storage battery 11 is typically a lithium-ion battery. The storage battery 11 supplies power to drive the motor 12. In addition, when starting the power generation system 10, the storage battery 11 supplies power to drive the generator 15. In principle, the storage battery 11 is charged with the power generated by the power generation system 10. However, the storage battery 11 can also be charged with the power generated by the motor 12 through so-called regenerative control. In addition, the storage battery 11 also supplies power to the auxiliary equipment 17. The auxiliary equipment 17 is equipment that requires power, such as the lights, speakers, vehicle navigation device, and air conditioner of the vehicle 100.

[0030] Various parameters indicating the state of the storage battery 11, such as the SOC (State of Charge), temperature, output power P out , and input power P in of the storage battery 11, can be appropriately detected or obtained through sensors (not shown) or calculations. The SOC is a parameter that serves as an indicator of the charge state (charge amount) of the storage battery 11.

[0031] The motor 12 is a driving motor, and generates a driving force in the vehicle 100 by the output torque. The motor 12 is connected to the drive wheels 20 via the gear 18 and the drive shaft 19. Therefore, the torque output by the motor 12 causes the drive wheels 20 to generate a driving force. The rotation speed of the motor 12 (hereinafter referred to as the motor speed NM )), torque (hereinafter referred to as motor torque T M ) and other various parameters representing the operating state of the motor 12 can be appropriately detected or obtained through sensors (not shown) or calculations or the like.

[0032] The vehicle controller 13 is a control device that uniformly controls each part of the vehicle 100 using the engine controller 21, the generator controller 22, the motor controller 23, the battery controller 24, etc. These controllers are composed of one or more arithmetic units and are programmed to control each part of the vehicle 100 at a specified control cycle. In addition, these controllers sometimes include circuits, sensors, etc. for controlling each part of the vehicle 100 as needed. In the present embodiment, for example, the generator controller 22 includes an inverter for controlling the power input to and output from the generator 15.

[0033] In addition, all or part of these controllers constitute a control device for controlling a specific part of the vehicle 100, such as a device or system. For example, the vehicle controller 13, the engine controller 21, and the generator controller 22 constitute a control device for the power generation system 10. In particular, the vehicle controller 13, the engine controller 21, and the generator controller 22 constitute a starting control device for performing starting control of the power generation system 10. In addition, the vehicle controller 13 and the motor controller 23 constitute a drive control device for controlling the drive of the vehicle 100.

[0034] The vehicle controller 13 acquires parameters representing the operating states of the respective parts constituting the vehicle 100, and uses these parameters to control the respective parts of the vehicle 100.

[0035] Specifically, the vehicle controller 13 acquires the engine oil temperature T oil , the engine speed N E , the generator speed N G , the engine torque T E , the generator torque T G , the SOC of the battery 11, the outputtable power P of the battery 11 out , and the inputtable power P of the battery 11 in . Moreover, the vehicle controller 13 controls the start and power generation of the power generation system 10 based on these parameters.

[0036] When the power generation system 10 generates power, the vehicle controller 13 calculates the power generation amount requested for the power generation system 10 (hereinafter referred to as the requested power generation amount) based on the SOC of the battery 11, etc. Then, the vehicle controller 13 calculates the engine torque target value T E * and the target speed N G * for realizing the requested power generation amount according to the requested power generation amount, and sets the engine torque target value T E*Input to the engine controller 21, and the target revolution speed N G *Is input to the generator controller 22. Thus, the engine controller 21 performs torque control on the engine 14 so that the engine torque T E Is consistent with the engine torque target value T E *And the generator controller 22 performs revolution speed control on the generator 15 so that the generator revolution speed N G Is consistent with the target revolution speed N G *And is consistent. Thus, the power generation system 10 generates electric power corresponding to the requested power generation amount and charges the storage battery 11.

[0037] When starting power generation while the power generation system 10 is in a stopped state, before the above power generation control, the vehicle controller 13 executes start control for starting the power generation system 10. In the start control, the vehicle controller 13 sets the target revolution speed N G *To a specified value preset according to the resonance frequency band B RF And inputs it to the generator controller 22. Then, the generator controller 22 performs revolution speed control so that the generator revolution speed N G Is consistent with the preset specified value, that is, the target revolution speed N G *And is consistent. Thus, the engine 14 performs electric drive. After that, the vehicle controller 13 ignites the engine 14 by giving the engine controller 21 permission to ignite the engine 14, and switches the control sequence of the power generation system 10 from start control to power generation control.

[0038] In addition, when executing the start control, the vehicle controller 13 is based on the generator revolution speed N G And the outputtable power P of the storage battery 11 out , sets the upper limit value of the torque for the generator 15 (hereinafter referred to as the upper limit torque ULT G ). Moreover, the vehicle controller 13 sets a torque target value (hereinafter, referred to as the generator torque target value T G *) set within the range of the upper limit torque ULT G For the generator 15. Therefore, the revolution speed control of the generator 15 in the start control is executed under the limitation based on the upper limit torque ULT G So that the generator torque T G Does not exceed the upper limit torque ULT G . In the present embodiment, in particular, the vehicle controller 13 calculates the upper limit torque ULT RF (resonance frequency ω p ) after the filtering process according to the resonance frequency band B of the power generation system 10 G-flt , and there are cases where it is used. Regarding the start control of the power generation system 10, especially in order to reduce the resonance frequency band B RFThe upper limit torque ULT after filtering based on the components of G-flt The starting control performed under the limitation of will be described in detail later.

[0039] In addition, the vehicle controller 13 controls the drive of the vehicle 100 based on the accelerator opening A po and the motor speed N M and so on. Specifically, the vehicle controller 13 calculates the target value of the torque that the motor 12 should output, that is, the motor torque target value T po *, based on the accelerator opening A M and the motor speed N M *, and inputs it to the motor controller 23. The motor controller 23 performs torque control so that the output torque of the motor 12 is consistent with the motor torque target value T M *. Thus, the vehicle 100 is driven by the driving force requested according to the accelerator opening A po . In addition, the accelerator opening A po is a parameter representing the operation amount of an accelerator pedal (not shown), and is appropriately detected using a sensor (not shown) or the like.

[0040] The battery controller 24 controls the input and output of the power of the battery 11 according to requests from the vehicle controller 13 and so on. In addition, the battery controller 24 measures the SOC, the outputtable power P out and the inputtable power P in and so on of the battery 11, and outputs them to the vehicle controller 13.

[0041] Hereinafter, the starting control of the power generation system 10 in the above various controls will be described in detail.

[0042] (Starting control of the power generation system)

[0043] Figure 2 is an explanatory diagram showing the starting mode of the power generation system 10 corresponding to the temperature of the engine 14 (engine oil temperature T oil ) and the outputtable power P out of the battery 11. As Figure 2 shown, the starting mode of the power generation system 10 includes a normal starting mode S N and an extremely low temperature starting mode S LT .

[0044] The normal starting mode S N is the starting mode selected when the temperature of the engine 14, that is, the engine oil temperature T oil is higher than a preset specified temperature TH oil . In addition, the normal starting mode S N is to drive electrically until the generator speed N G (and the engine speed NE ) higher than the resonance frequency band B of the power generation system 10 and becomes a specified rotational speed TH at which it is difficult to generate acoustic vibration in parts other than the power generation system 10 RF After that, a starting mode for igniting the engine 14. The frequency band (rotational speed band) in which acoustic vibration is generated in parts other than the power generation system 10 is usually located in a frequency band higher than the resonance frequency band B of the power generation system 10 NGn After that, a starting mode for igniting the engine 14. The frequency band (rotational speed band) in which acoustic vibration is generated in parts other than the power generation system 10 is usually located in a frequency band higher than the resonance frequency band B of the power generation system 10 RF Higher frequency band.

[0045] Ultra-low temperature starting mode S LT is a starting mode selected when the engine oil temperature T oil is at a specified temperature TH oil or lower. Ultra-low temperature means the temperature when the engine oil temperature T oil is at a specified temperature TH oil or lower.

[0046] In addition, the ultra-low temperature starting mode S LT has a first ultra-low temperature starting mode S LT1 and a second ultra-low temperature starting mode S LT2 . The first ultra-low temperature starting mode S LT1 and the second ultra-low temperature starting mode S LT2 are selected based on the relationship between the output power (hereinafter referred to as the required power NP out ) necessary for driving the generator 15 in the starting control and the actual output power P out of the battery 11.

[0047] When the output power P out of the battery 11 is out equal to or higher than the required power NP LT1 , the first ultra-low temperature starting mode S LT1 is selected. The first ultra-low temperature starting mode S G (and the engine rotational speed N E ) is a starting mode in which the engine 14 is ignited after being electrically driven by the power of the battery 11 to a specified rotational speed TH RF higher than the resonance frequency band B of the power generation system 10 NG1 . The specified rotational speed TH LT1 in the first ultra-low temperature starting mode S NG1 is set within the range where acoustic vibration is generated in parts other than the power generation system 10. That is, TH NGn >TH NG1 , compared with the normal starting mode S N , the first ultra-low temperature starting mode S LT1 is a starting mode that starts the power generation system 10 ignoring the request for reducing acoustic vibration in parts other than the power generation system 10.

[0048] When the output power P of the storage battery 11 out is less than the required power NP out the second extremely low temperature starting mode S is selected LT2 . That is, when the power of the storage battery 11 is insufficient and the power of the storage battery 11 cannot be used to electrically drive the generator speed N G (and the engine speed N E ) to a speed higher than the resonance frequency band B of the power generation system 10 RF the second extremely low temperature starting mode S is selected LT2 . Or, when it is possible to electrically drive to a target speed N RF higher than the resonance frequency band B G *but it also takes a long time, the second extremely low temperature starting mode S is selected LT2 . Moreover, in the second extremely low temperature starting mode S LT2 with the engine 14 ignited in a state where it is electrically driven to a specified speed TH RF lower than the resonance frequency band B NG2 . Therefore, the second extremely low temperature starting mode S LT2 is an "extremely low temperature and low rotation starting mode" where it is electrically driven to a specified speed TH RF lower than the resonance frequency band B NG2 .

[0049] Figure 3 is an explanatory diagram showing the change in the generator speed N LT1 in the first extremely low temperature starting mode S G and the ignition timing t F of the engine 14. In the scenario where the first extremely low temperature starting mode S LT1 is selected, even in an extremely low temperature environment, the storage battery 11 can supply sufficient power to meet the required power NP out . Therefore, as Figure 3 shown, electric drive is performed from the start of the power generation system 10 until it exceeds the specified speed TH RF of the resonance frequency band B NG1 to pass through the resonance frequency band B RF as quickly as possible, and then the engine 14 is ignited.

[0050] However, in an extremely low temperature environment, usually the output power P of the storage battery 11 out decreases, and in addition, the viscosity of the engine oil temperature T oil increases, so that the storage battery 11 sometimes cannot meet the required power NP out .

[0051] Figure 4 is a diagram showing the SOC and temperature T of the storage battery 11LB and the output power P out is shown in the explanatory diagram. As Figure 4 shown, even when the SOC of the storage battery 11 is high, when the temperature of the storage battery 11 is low, the output power P out also decreases. Therefore, in an extremely low temperature environment, the performance of the storage battery 11 will become a state where it is particularly reduced, and sometimes the output power P out will decrease to a level where it cannot meet the required power NP out .

[0052] Figure 5 represents the engine oil temperature T oil and the absolute viscosity V of the engine oil abs is shown in the curve diagram. As Figure 5 shown, when the engine oil temperature T oil decreases, the absolute viscosity V of the engine oil abs increases exponentially. Therefore, in an extremely low temperature environment, sometimes it will become a state where the frictional resistance of the engine 14 increases extremely. In an extremely low temperature environment, it is necessary to overcome such frictional resistance to electrically drive the engine 14. Therefore, as the engine oil temperature T oil decreases, the required power NP out also increases exponentially (refer to Figure 2 ). Moreover, when the storage battery 11 cannot supply the required power NP out in an extremely low temperature environment, low-speed rotation starting based on the second extremely low temperature starting mode S LT2 is required.

[0053] Figure 6 is an explanatory diagram showing the change in the generator speed N LT2 in the second extremely low temperature starting mode S G , the ignition timing t F of the engine 14, and the change in the generator torque T G . Figure 6 (A) shows the change in the generator speed N LT2 in the second extremely low temperature starting mode S G and the ignition timing t F of the engine 14. In addition, Figure 6 (B) shows the change in the generator torque T LT2 in the second extremely low temperature starting mode S G .

[0054] As Figure 6 (A) and Figure 6 (B) shown, the second extremely low temperature starting mode S LT2 has a first stage Ph 1 , a second stage Ph2 and the control phase of the third stage Ph 3 .

[0055] The first stage Ph 1 is the control phase of performing an electric drive to a specified rotational speed TH RF lower than the resonance frequency band B NG2 and igniting the engine 14. In this first stage Ph 1 , the start (drive) of the engine 14 is assisted by the electric drive so that the engine 14 can output an engine torque T NG2 in such a low rotational speed state as the specified rotational speed TH E .

[0056] The second stage Ph 2 is the control phase of exceeding the resonance frequency band B as quickly as possible through the cooperation of the electric drive of the generator 15 and the engine torque T E (compression reaction force) generated by the combustion of the engine 14 RF . In the present embodiment, in the second stage Ph 2 , the generator rotational speed N G and the engine rotational speed N E are increased to the specified rotational speed TH LT1 achieved in the case of the first extremely low temperature start mode S NG1 .

[0057] The third stage Ph 3 is the control phase of transferring from the start control based on the second extremely low temperature start mode S LT2 to the normal power generation control

[0058] Figure 6 (B) The dashed line schematically shows the approximate change of the upper limit torque ULT G for the generator torque T G . Using the outputtable power P out of the storage battery 11, the generator rotational speed N G , and a preset specified conversion coefficient C, the upper limit torque ULT G is calculated according to the following formula (1). That is, the upper limit torque ULT G represents the maximum generator torque T out that the generator 15 can output through the outputtable power P G of the storage battery 11

[0059] Formula (1):

[0060]

[0061] In the outputtable power P outWith respect to the necessary power NP out When it is large enough, the upper limit torque ULT G becomes a value that is much larger than the range in which the generator speed N G varies due to speed control. Therefore, in the first extremely low temperature start mode S LT1 and so on, the generator torque T G is hardly restricted by the upper limit torque ULT G . However, if a scenario such as the second extremely low temperature start mode S LT2 is selected, when the output power P out of the storage battery 11 is small, the upper limit torque ULT G also decreases accordingly. Therefore, the upper limit torque ULT G approaches the range in which the generator speed N G varies due to speed control, and there is a case where the generator torque T G is restricted by the upper limit torque ULT G .

[0062] In particular, the second stage Ph 2 is a control stage that increases the generator speed N G and the engine speed N E . Therefore, the generator speed N G which is the denominator of formula (1) increases. Therefore, as shown in Figure 6 (B), especially in the second stage Ph 2 , the generator torque T G is particularly close to the upper limit torque ULT G , and there is a case where the generator torque T G is restricted by the upper limit torque ULT G . Moreover, the generator torque T G based on the upper limit torque ULT G has a response delay in speed control. Therefore, by performing speed control, it instead promotes the variation of the generator speed N G . As a result, the generator speed N G and the engine speed N E stagnate in the resonance frequency band B RF , and cannot quickly pass through the resonance frequency band B RF , and the second stage Ph 2 becomes longer. That is, when the generator torque T G is restricted by the upper limit torque ULT G , vibrations are likely to occur in the power generation system 10.

[0063] Figure 7 represents the engine torque T in the case of performing speed control in the second extremely low temperature start mode S LT2 ​E and the engine torque T G explanatory drawing. Figure 7 (A) represents the ideal engine torque T LT2 when performing rotational speed control in the second extremely low temperature starting mode S E and the generator torque T G change. As Figure 7 (A) shows, the engine torque T E and the generator torque T G have a prescribed phase difference determined by the characteristics of the power transmission mechanism 16 etc. Figure 7 (B) represents the engine torque T LT2 when performing rotational speed control in the second extremely low temperature starting mode S E and the generator torque T G actual change. As Figure 7 (B) shows, the actual generator torque T G vibrates and changes due to rotational speed control. Moreover, the upper limit torque ULT G is calculated using the generator rotational speed N G that vibrates due to rotational speed control, so according to the change of the generator rotational speed N G it vibrates and changes. Therefore, when in the second extremely low temperature starting mode S LT2 the upper limit torque ULT G is close to the generator torque T G for example, as shown from A1 to A3 in Figure 7 (B), the generator torque T G crosses the upper limit torque ULT G and is restricted by the upper limit torque ULT G . Therefore, as described above, the change of the generator rotational speed N G is promoted and it cannot quickly pass through the resonance frequency band B RF , generating vibration from the power generation system 10.

[0064] Then, in the present embodiment, in the second extremely low temperature starting mode S LT2 (especially the second stage Ph 2 ), instead of the above upper limit torque ULT G , the upper limit torque ULT RF filtered in such a way as to reduce the components of the resonance frequency band B G-flt (hereinafter, simply referred to as the upper limit torque ULT G-flt ) is used, and the rotational speed control of the generator 15 is performed under the limitation based on this upper limit torque ULT G-flt . The filtered upper limit torque ULT G-flt is calculated according to the following formula (2).

[0065] Formula (2):

[0066]

[0067] As shown in Formula (2), the upper limit torque ULT G-flt does not perform a filtering process on the upper limit torque ULT calculated by Formula (1), but instead operates by performing a filtering process on the generator speed N G . That is, the vehicle controller 13 performs a filtering process on the generator speed N G to reduce the resonant frequency band B G component, and calculates the generator speed N after the filtering process RF (hereinafter simply referred to as the generator speed N G-flt ). Then, the vehicle controller 13 calculates the upper limit torque ULT G-flt based on this generator speed N G-flt and the available output power P of the battery 11 out . G-flt .

[0068] (Function)

[0069] Hereinafter, the function of the start control of the power generation system 10 in the vehicle 100 configured as described above will be described.

[0070] Figure 8 is a flowchart regarding the selection of the start mode. As Figure 8 shown, in step S11, the vehicle controller 13 acquires the engine oil temperature T oil and the available output power P of the battery 11 out and so on. In step S12, the vehicle controller 13 determines whether the engine oil temperature T oil is less than the specified temperature TH oil . When the engine oil temperature T oil is equal to or higher than the specified temperature TH oil , it proceeds to step S13, and the vehicle controller 13 starts the power generation system 10 in the normal start mode S N .

[0071] On the other hand, when it is determined in step S12 that the engine oil temperature T oil is less than the specified temperature TH oil , it proceeds to step S14, and the vehicle controller 13 calculates the required power NP oil based on the engine oil temperature T out . The vehicle controller 13, for example, previously has a mapping diagram that correlates the engine oil temperature T oil and the required power NP out through experiments or simulations. Therefore, the vehicle controller 13 refers to this mapping diagram and, based on the engine oil temperature Toil Necessary power for operation NP out .

[0072] In step S15, the vehicle controller 13 determines whether the calculated necessary power NP out is greater than the output power P of the battery 11 out . When it is determined that the necessary power NP out is the output power P of the battery 11 out Hereinafter, when sufficient electric drive exceeding the resonance frequency band B can be performed by the power of the battery 11 RF , the process proceeds to step S16. Then, in step S16, the vehicle controller 13 starts the power generation system 10 in the first extremely low temperature start mode S LT1 .

[0073] On the other hand, when it is determined in step S15 that the necessary power NP out is less than the output power P of the battery 11 out , and sufficient electric drive exceeding the resonance frequency band B cannot be performed by the power of the battery 11 RF , the process proceeds to step S17. Then, in step S17, the vehicle controller 13 starts the power generation system 10 in the second extremely low temperature start mode S LT2 .

[0074] Figure 9 is a flowchart of the rotational speed control based on the second extremely low temperature start mode S LT 2. As Figure 9 shown, in step S21, the vehicle controller 13 calculates, based on the output power P of the battery 11 out , the maximum torque that can be output by the generator 15 within the range of the output power P out (hereinafter, referred to as the maximum power operation torque T GM ). In step S22, the vehicle controller 13 calculates the upper limit torque ULT out based on the output power P of the battery 11 G and the generator rotational speed N G-flt . That is, the vehicle controller 13 performs a filtering process on the obtained generator rotational speed N G to reduce the components of the resonance frequency band B RF , calculates the generator rotational speed N G-flt , and uses it to calculate the upper limit torque ULT G-flt according to Equation (2). Then, in step S24, the vehicle controller 13 sets the torque within the range of limiting the maximum power operation torque T GM to the upper limit torque ULT G-flt as the generator torque target value T G*, in addition, in step S25, the vehicle controller 13 sets the target rotational speed N G * to a first target rotational speed N RF * that is lower than the resonance frequency band B G1 *. In this embodiment, the first target rotational speed N G1 * is the above-mentioned specified rotational speed TH NG2 . Thus, by setting the generator torque target value T G * and the target rotational speed N G *, the generator controller 22 performs rotational speed control within the range where the generator torque T G does not exceed the upper limit torque ULT G-flt so that the generator rotational speed N G is consistent with the first target rotational speed N G1 *.

[0075] In step S26, the vehicle controller 13 determines whether the generator rotational speed N G has reached the first target rotational speed N G1 *. Then, when it is determined that the generator rotational speed N G has reached the first target rotational speed N G1 *, in step S27, the vehicle controller 13 allows fuel injection into the engine 14 to start the engine 14. In addition, in step S27, the vehicle controller 13 sets the engine torque target value T E * to the starting engine torque target value T E1 * (not shown). Then, in step S28, the vehicle controller 13 determines whether the engine 14 stably outputs the engine torque T E by monitoring the engine torque T E , that is, whether it stably becomes T E >0. The control up to this point is the control of the first stage Ph LT2 in the second extremely low temperature starting mode S 1 . Then, when it is determined in step S28 that the engine torque T E is stably output, the vehicle controller 13 transfers to the control of the second stage Ph 2 .

[0076] As shown in step S29, in the control of the second stage Ph 2 , the vehicle controller 13 sets the target rotational speed N G * to a second target rotational speed N G that raises the generator rotational speed N RF to a rotational speed higher than the resonance frequency band B NG1 (for example, the above-mentioned specified rotational speed TH G2*, in addition, in step S30, in order to quickly pass through the resonance frequency band B RF , the vehicle controller 13 sets the engine torque target value T E * to the engine torque target value T E2 * for increasing the rotational speed in cooperation with the generator 15. Thus, the generator rotational speed N G and the engine rotational speed N E increase toward the second target rotational speed N G2 *. In addition, in step S31, the vehicle controller 13 determines whether the generator rotational speed N G or the engine rotational speed N E has reached the second target rotational speed N G2 *. In the present embodiment, the vehicle controller 13 monitors the engine rotational speed N E , and determines whether the engine rotational speed N E has reached the second target rotational speed N G2 *. The control up to now is the control of the second stage Ph LT2 in the second extremely low temperature starting mode S 2 . Then, in step S31, when it is determined that the engine rotational speed N E (or the generator rotational speed N G ) has reached the second target rotational speed N G2 *, the vehicle controller 13 executes the control of the third stage, that is, the transfer control to the power generation control.

[0077] As shown in step S32, in the control of the third stage Ph 3 , the vehicle controller 13 sets the target rotational speed N G * to the rotational speed suitable for the power generation control, that is, the third target rotational speed N G3 *. In addition, in step S33, the vehicle controller 13 gradually reduces the engine torque target value T E *. Then, in step S34, the vehicle controller 13 finally sets the engine torque target value T E * to the engine torque target value T E3 * corresponding to the requested power generation amount. Thus, the starting control based on the second extremely low temperature starting mode S LT2 ends, and the control transfers to the normal power generation control.

[0078] Figure 10 is a graph showing a comparison example of torque and rotational speed in the case where the starting control of the second extremely low temperature starting mode S G is executed using the upper limit torque ULT LT2 without filtering processing in an extremely low temperature environment. Figure 10 (A), the solid line represents the generator torque T G, the dashed line indicates the upper limit torque ULT G . Additionally, Figure 10 (B), the solid line represents the generator speed N G , and the dash-dotted line represents the target speed N G *.

[0079] As Figure 10 (A) shows, in the scenario where the second extremely low temperature starting mode S LT2 is selected, the upper limit torque ULT G is extremely close to the generator torque T G . Therefore, as shown by the downward arrow, the generator torque T G is sometimes restricted by the upper limit torque ULT G . Here, in the second stage Ph 2 , the generator torque T G is restricted by the upper limit torque ULT G four times. Then, as Figure 10 (B) shows with the upward arrow, as the generator torque T G is restricted by the upper limit torque ULT G , the generator speed N G controlled by speed control will exacerbate the vibration. As a result, the time required for the second stage Ph 2 becomes the time t A .

[0080] Figure 11 is a graph showing an embodiment of torque and speed in the case of performing starting control of the second extremely low temperature starting mode S G-flt using the filtered upper limit torque ULT LT2 in an extremely low temperature environment. Figure 11 (A), the solid line represents the generator torque T G , and the dashed line represents the upper limit torque ULT G-flt . Additionally, Figure 11 (B), the solid line represents the generator speed N G , and the dash-dotted line represents the target speed N G *.

[0081] As Figure 11 (A) shows with the downward arrow, in the case of using the filtered upper limit torque ULT G-flt , the generator torque T G is sometimes also restricted by this upper limit torque ULT G-flt . Here, in the second stage Ph 2 , the generator torque T G is restricted by the upper limit torque ULT G twice. However, asFigure 11 As shown by the upward arrow in (B), when the upper limit torque ULT after the filtering process is used G-flt even though the generator torque T G is restricted by the upper limit torque ULT G-flt the vibration of the generator speed N controlled by the speed control is reduced. As a result, the time required for the second stage Ph G becomes shorter than the time t 2 in the case where the upper limit torque ULT without the filtering process is used G and is the short time t A . B .

[0082] As described above, even when the output power P of the storage battery 11 is insufficient in an extremely low temperature environment and it is not possible to quickly pass through the resonance frequency band B of the power generation system 10 by simple electric drive out in the case of, according to the second extremely low temperature start mode S RF using the upper limit torque ULT after the filtering process G-flt it is also possible to quickly pass through the resonance frequency band B LT2 . As a result, the vibration generated in the power generation system 10 is reduced or suppressed. RF .

[0083] In addition, when the generator speed N G and the engine speed N E stagnate in the resonance frequency band B of the power generation system 10 RF the phase difference between the generator speed N G and the engine speed N E increases and sometimes exceeds the allowable limit of a damper or the like constituting the power transmission mechanism 16. However, as described above, according to the second extremely low temperature start mode S G-flt using the upper limit torque ULT after the filtering process LT2 it is possible to quickly pass through the resonance frequency band B RF and thus the occurrence of such an adverse situation is also reduced or suppressed.

[0084] (Modification example)

[0085] Hereinafter, a modification example of the start control based on the second extremely low temperature start mode S LT2 of the above-described embodiment will be described.

[0086] In the above-described embodiment, in the speed control of the generator 15, the upper limit torque ULT that has been filtered in such a way as to reduce the components of the resonance frequency band B RF is used. However, if the upper limit torque ULT after such filtering is used G-flt G-flt ​There is a case where the actual power consumption of the generator 15 exceeds the output power P of the storage battery 11. out Case.

[0087] Figure 12 Indicates the output power P of the storage battery 11 out And the curve graph of the actual power consumption of the generator 15. Figure 12 (A) Represents the case where the upper limit torque ULT without filtering process is used G Change of the power consumption of the generator 15 in this case. Figure 12 (B) Represents the case where the upper limit torque ULT after filtering process is used G-flt Change of the power consumption of the generator 15 in this case.

[0088] As Figure 12 (A) shows, when the upper limit torque ULT without filtering process is used in the rotation speed control of the generator 15 G In this case, the power consumption of the generator 15 generally fluctuates within the range below the output power P of the storage battery 11 out Even if it exceeds the output power P of the storage battery 11 out , it is only for a very short and extremely short time. On the other hand, as Figure 12 (B) shows, when the upper limit torque ULT after filtering process is used in the rotation speed control of the generator 15 G-flt In this case, the power consumption of the generator 15 sometimes intentionally exceeds the output power P of the storage battery 11 out . For example, when the change of the generator rotation speed N G Is sharp, or when the output power P out Changes sharply due to the abnormality of the storage battery 11 or the like, the power consumption of the generator 15 may exceed the output power P of the storage battery 11 out . When the power consumption of the generator 15 exceeds the output power P of the storage battery 11 out , it will cause deterioration or damage of the storage battery 11. In addition, it sometimes becomes a situation where the power supply from the storage battery 11 is cut off by a relay circuit (not shown).

[0089] Therefore, as shown in the following formula (3), it is preferable to set a preset specified margin δ out For the output power P of the storage battery 11 M And calculate the upper limit torque ULT G-flt .

[0090] Formula (3)

[0091]

[0092] Thus, by setting a margin δ for the output power P of the storage battery 11 out the consumption power of the generator 15 can be more reliably suppressed within the range not exceeding the output power P of the storage battery 11 M . That is, by setting a margin δ for the output power P of the storage battery 11 out the starting control of the second extremely low temperature starting mode S out can quickly pass through the resonance frequency band B while ensuring safety M . LT2 . RF

[0093] Figure 13 FIG. is an explanatory diagram showing the effect of the margin δ set for the output power P of the storage battery 11 out . As shown in M the upper limit torque ULT calculated by setting the margin δ Figure 13 is reliably smaller by approximately the amount of the margin δ than the upper limit torque ULT without the filtering process M . Therefore, the consumption power of the generator 15 is reliably within the range of the output power P of the storage battery 11 G-flt . G M . out

[0094] In addition, in this modification, the margin δ M is a preset fixed value, but the margin δ M is preferably a variable value corresponding to the temperature of the engine 14 (engine oil temperature T oil ). As described above, the lower the temperature of the engine 14, the more exponentially the required power NP out increases. Therefore, the lower the temperature of the engine 14, the greater the actual consumption power of the generator 15. Therefore, by setting the margin δ M as a variable value corresponding to the temperature of the engine 14, and for example, setting the margin δ M to increase exponentially as the temperature of the engine 14 decreases, safety is ensured regardless of the temperature of the engine 14

[0095] As described above, in the starting control method of the power generation system according to the above embodiment, when starting the power generation system 10 including an internal combustion engine (14) as a power source, a generator (15), and a power transmission mechanism (16) that transmits power between the internal combustion engine (14) and the generator (15), the generator (15) is driven by the power supplied from the storage battery (11), and the rotational speed (N G ) of the generator (15) is made to match the target rotational speed (N G ​​​*) Consistent revolution speed control. In the starting control method of this power generation system, the available output power (P out ) of the storage battery (11) is obtained, and the revolution speed (N G ) of the generator (15) is obtained. In addition, filtering processing is performed on the revolution speed (N G ) of the generator (15) to reduce the components of the resonance frequency band (B RF ) of the spring mass system composed of the internal combustion engine (13), the generator (15), and the power transmission mechanism (16). Furthermore, based on the filtered revolution speed (N G-flt ) of the generator (15) and the available output power (P out ), the upper limit value of the torque (T G ) for the generator (15), that is, the upper limit torque (ULT G-flt ), is calculated. Moreover, revolution speed control is performed under the limitation based on this upper limit torque (ULT G-flt ).

[0096] In this way, by performing starting control using the upper limit torque ULT G-flt in the second extremely low temperature starting mode, even when the available output power P out of the storage battery 11 is insufficient in an extremely low temperature environment, it is possible to quickly pass through the resonance frequency band B RF . As a result, the vibration generated in the power generation system 10 can be reduced or suppressed. In addition, by being able to quickly pass through the resonance frequency band B RF , it is possible to reduce or suppress the occurrence of defects exceeding the allowable limit of dampers and the like constituting the power transmission mechanism 16.

[0097] In addition, particularly in the starting control method of the power generation system in the above modification, a margin (δ out ) is set for the available output power (P M ), and based on the filtered revolution speed (N G-flt ) of the generator (15) and the deviation (P out ) obtained by subtracting the margin (δ M ) from the available output power (P out - δ M ), the upper limit torque (ULT G-flt ) is calculated. In this way, by setting a margin δ out for the available output power P M of the storage battery 11, the power consumption of the generator 15 does not exceed the available output power P out of the storage battery 11. That is, the starting control method of the power generation system in the above modification can quickly pass through the resonance frequency band B RF while ensuring safety.

[0098] In addition, in the starting control method of the power generation system of the above-described modification, the margin (δ M ) is a variable value corresponding to the temperature of the internal combustion engine (14). Thus, by making the margin δ M a variable value corresponding to the temperature of the internal combustion engine (14), it is possible to particularly ensure safety regardless of the temperature of the specific engine (14).

[0099] In the starting control method of the power generation system of the above-described embodiment and modification, at least when the temperature of the internal combustion engine (14) is equal to or lower than a preset specified temperature (TH oil ) and the output power (P out ) is less than the power (NP out ) necessary to drive the generator (15), the rotation speed control is performed under the limitation of the upper limit torque (ULT G-flt ) after the filtering process. That is, at least in the second extremely low temperature starting mode S LT2 , the rotation speed control of the generator 15 is performed under the limitation of the upper limit torque ULT G-flt after the filtering process. As described above, in a scenario where it is necessary to start the power generation system 10 based on the second extremely low temperature starting mode S LT2 , particularly during the control period of the second stage Ph 2 , the generator rotation speed N G and the engine rotation speed N E are likely to stagnate in the resonance frequency band B RF . Therefore, as described above, by performing the rotation speed control under the limitation of the upper limit torque ULT G-flt , it is easy to shorten the control period of the second stage Ph 2 . That is, the starting control method of the power generation system of the above-described embodiment and modification is particularly effective when implemented in the second extremely low temperature starting mode S LT2 .

[0100] In addition, in the starting control method of the power generation system of the above-described embodiment and modification, the target rotation speed (N G *) is set to a rotation speed lower than the resonance frequency band (B RF ), that is, the first target rotation speed (N G1 *), and the internal combustion engine (14) is ignited. After this ignition, when the internal combustion engine (14) starts to output torque by combustion, the target rotation speed (N G *) is set to rise from the first target rotation speed (N G1 *) to a second target rotation speed (N G ) that makes the rotation speed (N RF ) higher than the resonance frequency band (B G2 *). Moreover, at least when the target rotation speed (N G *) is set to the second target rotation speed (NG2 *) When performing speed control under the limit of the upper torque (ULT G-flt ) after filtering. That is, at least in the second stage Ph LT2 of the second extremely low temperature start-up mode S 2 , perform speed control under the limit of the upper torque ULT G-flt after filtering. As described above, in the second stage Ph LT2 of the second extremely low temperature start-up mode S 2 , the generator torque T G is restricted by the unfiltered upper torque ULT G , and the generator speed N G and the engine speed N E are likely to stagnate in the resonance frequency band B RF . Therefore, as described above, at least in the control of the second stage Ph 2 , by using the filtered upper torque ULT G-flt , it is difficult for the generator speed N G and the engine speed N E to stagnate in the resonance frequency band B RF . That is, the start-up control method of the power generation system of the above-described embodiment and modification is particularly effective when implemented in the second stage Ph LT2 of the second extremely low temperature start-up mode S 2 .

[0101] In addition, the start-up control device of the power generation system of the above-described embodiment and modification includes a controller (13). When starting the power generation system including an internal combustion engine (14) as a power source, a generator (15), and a power transmission mechanism (16) that transmits power between the internal combustion engine (14) and the generator (15), the controller (13) drives the generator (15) using the power supplied from the battery (11), and performs speed control to make the speed (N G ) of the generator (15) coincide with the target speed (N G *). The controller (13) obtains the available output power (P out ) of the battery (11) and obtains the speed (N G ). In addition, the controller (13) performs filtering on the speed (N G ) to reduce the components of the resonance frequency band (B RF ) of the spring mass system composed of the internal combustion engine (14), the generator (15), and the power transmission mechanism (16). Furthermore, the controller (13) calculates the torque (T G for the generator (15) based on the filtered speed (N G-flt ) and the available output power (P out )) The upper limit value, i.e., the upper limit torque (ULT G-flt ). Moreover, the controller (13) is configured to perform the rotational speed control under the limitation based on this upper limit torque (ULT G-flt ).

[0102] As described above, the embodiments of the present invention have been described. However, the structures described in the above embodiments and each modification only represent a part of the application examples of the present invention, and do not limit the technical scope of the present invention.

Claims

1. A starting control method for a power generation system. When starting a power generation system including an internal combustion engine as a power source, a generator, and a power transmission mechanism for transmitting power between the internal combustion engine and the generator, the generator is driven by power supplied from a storage battery, and a speed control for making the speed of the generator coincide with a target speed is performed. Wherein, the available output power of the storage battery is obtained, the speed is obtained, based on the speed and the available output power, the upper limit value of the torque for the generator, i.e., the first upper limit torque, is calculated, filtering processing for reducing the components of the resonance frequency band of the spring mass system composed of the internal combustion engine, the generator, and the power transmission mechanism is performed on the speed, based on the filtered speed and the available output power, the upper limit value of the torque for the generator, i.e., the second upper limit torque, is calculated, when the temperature of the internal combustion engine is greater than a preset specified temperature, or when the available output power is not less than the power necessary to drive the generator, the speed control is performed under the limitation based on the first upper limit torque, when the temperature of the internal combustion engine is below the specified temperature and the available output power is less than the power necessary to drive the generator, the speed control is performed under the limitation based on the second upper limit torque.

2. The starting control method for a power generation system according to claim 1, wherein, a margin is set for the available output power, based on the filtered speed and the deviation obtained by subtracting the margin from the available output power, the second upper limit torque is calculated.

3. The starting control method for a power generation system according to claim 2, wherein, the margin is a variable value corresponding to the temperature of the internal combustion engine.

4. The starting control method for a power generation system according to claim 1, wherein, the target speed is set to a speed lower than the resonance frequency band, i.e., the first target speed, the internal combustion engine is ignited, after the ignition, when the internal combustion engine starts to output torque by combustion, the target speed is set to a second target speed that causes the speed to rise from the first target speed to a speed higher than the resonance frequency band, at least when the target speed is set to the second target speed, the speed control is performed under the limitation based on the second upper limit torque.

5. A starting control device for a power generation system, comprising a controller. When starting a power generation system including an internal combustion engine as a power source, a generator, and a power transmission mechanism for transmitting power between the internal combustion engine and the generator, the controller drives the generator by power supplied from a storage battery, and performs a speed control for making the speed of the generator coincide with a target speed. Wherein, the starting control device of the power generation system is configured to make the controller perform the following processing: obtain the available output power of the storage battery, obtain the speed, based on the speed and the available output power, calculate the upper limit value of the torque for the generator, i.e., the first upper limit torque, perform filtering processing for reducing the components of the resonance frequency band of the spring mass system composed of the internal combustion engine, the generator, and the power transmission mechanism on the speed, Based on the filtered rotation speed and the outputtable power, calculate the upper limit value of the torque for the generator, i.e., the second upper limit torque. When the temperature of the internal combustion engine is greater than a preset specified temperature or when the outputtable power is equal to or greater than the power necessary to drive the generator, perform the rotation speed control under the limitation based on the first upper limit torque. When the temperature of the internal combustion engine is equal to or lower than the specified temperature and the outputtable power is less than the power necessary to drive the generator, perform the rotation speed control under the limitation based on the second upper limit torque.

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