JP2005269825A - Hybrid system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a hybrid system using a nickel hydride battery as a power storage unit in which charge/discharge efficiency is enhanced by performing charge/discharge control and voltage control of a capacitor power storage unit appropriately, the capacitor power storage unit is prevented from such damage as heat generation or deterioration, power storage capacity of the capacitor power storage unit can be estimated easily by utilizing the properties of an electric double layer capacitor, and an operator can grasps the power storage capacity being estimated. <P>SOLUTION: In the hybrid system comprising a capacitor power storage unit 21 for storing power generated by a generator and supplying power to a motor, and a chopper 22 for stepping the input/output voltage of the capacitor power storage unit 21 up and down, the step up/down chopper 22 is provided with a charge/discharge current limiter 55. Charge/discharge capacity of the capacitor power storage unit 21 is controlled by a charge/discharge current command being limited within a predetermined range by the charge/discharge current limiter 55. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a hybrid system that extracts at least mechanical driving force and electric power from an engine, and more particularly, to a power storage device in the hybrid system.

  In recent years, in working machines such as automobiles and construction machines, a generator using an engine as a drive source, a battery (secondary battery) as a power storage device that stores electric power generated by the generator, and supply from this battery A motor (electric motor) that is driven using the generated electric power, and the battery is stored by the generator and the engine is torque-assisted by the motor, so that the engine can be used effectively while saving energy. So-called hybrid systems that enable efficient operation are adopted, and such technology is becoming the mainstream in the future.

  In the hybrid system as described above, in order to enable a large amount of power to be supplied to the motor that assists the engine in a short time, such as when an automobile is accelerated or when a heavy work load is applied to the work machine. In addition, in order to improve the power regeneration efficiency of the power storage device by the generator, it is proposed to use an electric double layer capacitor having a low internal resistance, a high output density, and a high charge / discharge efficiency as a power storage device. (For example, refer to Patent Document 1).

JP 2002-120602 A

However, as described above, an electric double layer capacitor used as a power storage device generally has a very low internal resistance (about 1 mΩ) as compared with a battery. When electric power generated from a machine or other power storage device is stored as it is, a large current may flow instantaneously, which may cause damage to the electric double layer capacitor. Similarly, during charging, the withstand voltage is easily exceeded as the terminal voltage (capacitor voltage) of the electric double layer capacitor rises, which leads to deterioration of the electric double layer capacitor. Conversely, when power is supplied from the electric double layer capacitor, if the output is short-circuited in a state where the terminal voltage is high, an unlimited current flows and an overcurrent state occurs instantaneously, which may damage the electric double layer capacitor, The large current due to this overcurrent also affects other electronic devices attached to the electrical system, such as failure.
In addition, the electric double layer capacitor has such a property that when an overvoltage exceeding the rated voltage is applied, the resistance to the overvoltage is low, such as heat generation, significant characteristic deterioration, and further damage.

  Furthermore, when charging an electric double layer capacitor, if the electric double layer capacitor is composed of a plurality of modules, the electric double layer capacitor depends on the material properties of the activated carbon and the use conditions such as temperature and voltage. In general, since self-discharge is large, when the same charge amount is stored, the terminal voltage of each module varies, and although one module is fully charged immediately, another module is completely insufficient. A phenomenon that the battery is still charged may occur. In addition, in this case, the module that has been fully charged first is overcharged, and the module generates excessive heat.

  On the other hand, the electric double layer capacitor can easily and accurately estimate the charged amount (remaining capacity) compared to the battery. In other words, there are two methods for estimating the amount of charge of a battery, one based on voltage and one based on current integration. However, since the battery involves a chemical reaction in charge and discharge, it is difficult to accurately estimate the amount of charge. In this regard, the amount of electricity stored in the electric double layer capacitor that does not involve a chemical reaction in charge and discharge can be accurately estimated from the capacitance of the electric double layer capacitor after measuring the terminal voltage.

  Therefore, in the present invention, in a hybrid system including a capacitor power storage device as a power storage device, charging / discharging control and voltage control of the capacitor power storage device are appropriately performed to improve charge / discharge efficiency and heat generation of the capacitor power storage device. The purpose is to prevent deterioration and damage. It is another object of the present invention to make it possible to easily estimate the amount of electricity stored in the capacitor power storage device by utilizing the properties of the electric double layer capacitor and to easily grasp the estimated amount of electricity stored by an operator or the like.

  The problems to be solved by the present invention are as described above. Next, means for solving the problems will be described.

  That is, in claim 1, an engine, a motor that assists the engine, a control unit that controls these, a generator that drives the engine, a storage of generated power from the generator, and the motor A power storage device that supplies power to the power storage device, a step-up / step-down chopper that steps up / down the input / output voltage of the capacitor power storage device, and a power that is interposed between the motor and the step-up / down chopper and converts the input power to a predetermined value. The step-up / step-down chopper includes a charge / discharge current limiter, and the charge amount to the capacitor power storage device is determined by a charge current command limited to a predetermined range by the charge / discharge current limiter. And the amount of discharge from the capacitor power storage device.

  According to a second aspect of the present invention, the step-up / step-down chopper decreases the command value of the charging current command when the inverter DC voltage of the inverter converter is lower than the voltage command value from the control means, and Reducing the amount of charge to the device or discharging the capacitor power storage device, and if the inverter DC voltage is higher than the voltage command value, the command value of the charge current command is increased and the capacitor power storage device It is intended to increase the amount of charge.

  According to a third aspect of the present invention, the step-up / step-down chopper decreases the command value of the charging current command when the capacitor voltage exceeds a preset specified value, and the capacitor voltage falls below the specified value. In this case, the command value of the charging current command is increased, and when the capacitor voltage reaches the rated voltage value, the charging of the capacitor power storage device is stopped.

  According to a fourth aspect of the present invention, an engine, a motor that assists the engine, a control unit that controls the engine, a generator that uses the engine as a driving source, storage of generated power from the generator, and the motor A hybrid system including a capacitor power storage device that supplies power, and a constant current control circuit that performs constant current control of a charging current to the capacitor power storage device.

  In claim 5, when the capacitor voltage of the capacitor power storage device reaches a rated voltage value of the capacitor power storage device, an alarm is transmitted from the control means and charging to the capacitor power storage device is stopped. is there.

  According to a sixth aspect of the present invention, the capacitor power storage device includes a plurality of capacitor modules that are connected in a predetermined manner, and includes an equalization control circuit that equalizes voltages for the plurality of capacitor modules.

  8. The capacitor power storage device according to claim 7, wherein a capacitor voltage of the capacitor power storage device is output from the capacitor power storage device when a full charge signal output when the capacitor power storage device is fully charged is output. When the voltage difference with respect to the rated voltage exceeds a preset specified value, the charging current to the capacitor power storage device is set to a preset specified value, and when the capacitor voltage reaches the rated voltage, The charging of the capacitor power storage device is stopped.

  In claim 8, an engine, a motor that assists the engine, a control unit that controls these, a generator that uses the engine as a driving source, storage of electric power generated from the generator, and the motor A capacitor storage device that supplies power, and a map representing a relationship between a capacitor voltage and a storage amount of the capacitor storage device based on a pre-measured result It is created according to capacity, and the amount of stored electricity is estimated from the capacitor voltage based on the map.

  According to a ninth aspect of the present invention, display means connected to the control means is provided, and the estimated storage amount of the capacitor power storage device is displayed on the display means.

  As effects of the present invention, the following effects can be obtained.

According to the first aspect, the charging current to the capacitor power storage device can be set within a certain range (constant current), and a large current can be prevented from flowing instantaneously into the capacitor power storage device having a low internal resistance. The capacitor power storage device can be prevented from being damaged.
In addition, by controlling the amount of discharge from the capacitor power storage device, when power is supplied from the capacitor power storage device, the capacitor power storage device is prevented from being damaged due to an unlimited current flow and an instantaneous overcurrent state. In addition, the failure of other electronic devices due to overcurrent can be prevented.

  According to the second aspect, since the charge amount of the capacitor power storage device can be controlled according to the inverter DC voltage of the inverter converter, the capacitor power storage device can be appropriately charged and discharged, and the capacitor power storage It is possible to limit the discharge current by setting the charging current to the device within a certain range (constant current).

  According to the third aspect of the present invention, it is possible to prevent overcharge / overdischarge of the capacitor power storage device, protect the capacitor power storage device having a low internal resistance from overcurrent, and protect the capacitor power storage device from overvoltage. Thereby, since the capacitor power storage device can be prevented from being charged with a large current in a high voltage state, heat generation and characteristic deterioration of the capacitor power storage device can be suppressed.

  According to the fourth aspect of the present invention, it is possible to make the charging current to the capacitor power storage device constant, and it is possible to prevent a large current from flowing into the capacitor power storage device having a low internal resistance. Can be prevented.

  According to claim 5, it is possible to notify an operator or the like that the capacitor power storage device is in a high voltage state. As a result, the operator or the like can quickly cope with the high voltage state of the capacitor power storage device, such as stopping the operation of the generator.

  According to the sixth aspect of the present invention, it is possible to suppress variations in the terminal voltage of each capacitor module that are likely to occur during charging of the capacitor power storage device, particularly during rapid charging. Thereby, the charge amount of each capacitor module can be equalized, charging efficiency can be improved, and heat generation due to overcharging of a certain capacitor module can be suppressed. In addition, since the capacitor voltage of the capacitor power storage device can be kept constant, overcharging of the capacitor power storage device can be prevented and the life can be extended.

  According to the seventh aspect, the charge amount of each capacitor module of the capacitor power storage device can be equalized, the charging efficiency can be improved, and heat generation due to overcharging of a certain capacitor module can be suppressed. In addition, since the capacitor voltage of the capacitor power storage device can be kept constant, overcharge of the capacitor power storage device can be prevented.

  According to the eighth aspect of the present invention, the property of the capacitor power storage device capable of accurately estimating the power storage amount can be fully utilized, and the power storage amount of the capacitor power storage device according to the capacitance is measured only by the capacitor voltage. This makes it possible to easily estimate.

  According to the ninth aspect, it is possible to easily grasp the amount of electricity stored in the capacitor power storage device by an operator or the like. In other words, the characteristics of the capacitor power storage device that can accurately estimate the power storage amount can be fully exploited, and an operation according to the power storage amount of the capacitor power storage device can be performed on a work machine to which the hybrid system is applied. Can be done.

Next, embodiments of the invention will be described.
1 is a diagram showing an example of the configuration of a hybrid system according to the present invention, FIG. 2 is a block diagram for a buck-boost chopper, FIG. 3 is a diagram showing the configuration of a constant current control circuit, and FIG. 4 is a constant current by a constant current control circuit. FIG. 5 is a diagram showing the control flow of the control, FIG. 5 is a diagram showing the configuration of the equalization control circuit, FIG. 6 is a diagram showing the configuration of the power storage system unit using the fuel cell, and FIG. 7 is a storage amount estimation map of the capacitor power storage device FIG.

First, the configuration of the hybrid system will be described with reference to FIG.
In this embodiment, a hybrid system having a motor generator 11 having both functions of a motor and a generator will be described. However, the present invention is not limited to this, and a hybrid having a configuration in which a motor and a generator are separately provided. The effects of the present invention can also be obtained in a system or the like. That is, the present invention can be applied to a hybrid system including a capacitor power storage device (electric double layer capacitor) as a power storage device that supplies power to a motor that assists the engine and stores power generated by the generator.

  In this hybrid system, the output shaft of the engine 2 can be driven by both the engine 2 and the motor generator 11 that functions as a motor and a generator. The driving force extracted from the output shaft portion is transmitted to a load 7 such as a traveling portion or various working portions in an automobile or a work machine via a clutch portion or a power transmission device.

The motor generator 11 is attached with the drive shaft connected to the crankshaft of the engine 2, and is electrically connected to the power storage system unit 20 via the inverter converter 12.
Further, the motor generator 11 functions as a motor or a generator, performs torque assist of the engine 2 that drives the load 7 by functioning as a motor, and functions as a generator to generate the generated power and the load 7. The regenerative power generated by the inertial force on the side is stored in the power storage device.
The inverter converter 12 functions as an inverter or a converter, and converts input power into direct current or alternating current and also converts it into a predetermined voltage and frequency.
The power storage system unit 20 includes a capacitor power storage device 21 as a power storage device and a step-up / step-down chopper 22 that steps up and down the input / output voltage of the capacitor power storage device 21.
The power storage system unit 20 including the engine 2, the inverter converter 12, and the step-up / step-down chopper is connected to the system controller 1 as a control unit, and the hybrid system is controlled by the system controller 1. Yes.

Further, an operation lever 8 for operating the hybrid system includes an operation lever for adjusting the driving force (rotation speed) of the engine 2 and various switches for sending start signals and instruction signals to various devices (any of them) The control levers and various switches are connected to the system controller 1.
In the operation unit 8, as will be described in detail later, a display unit 14 such as a liquid crystal monitor that displays a storage amount (remaining capacity) of the capacitor storage device 21 is provided and connected to the system controller 1.

In the hybrid system having such a configuration, as described above, the motor generator 11 having functions as a motor and a generator exhibits each function in accordance with a work situation or the like.
When the motor generator 11 is operated as a motor, electric power is supplied from the capacitor power storage device 21 of the power storage system unit 20. The electric power supplied from the capacitor power storage device 21 is input to the inverter converter 12 via the step-up / step-down chopper 22. At this time, the step-up / step-down chopper 22 functions as a step-up chopper, boosts the voltage of the power supplied from the capacitor power storage device 21 to a predetermined voltage, and outputs it to the inverter converter 12. At this time, the inverter converter 12 functions as an inverter, converts the input power into a predetermined value, and supplies the converted power to the motor generator 11.
Thus, when the motor generator 11 operates as a motor, the driving force is transmitted from the driving shaft of the motor generator 11 connected to the crankshaft of the engine 2 to the engine 2 to perform torque assist.

  On the other hand, when the motor generator 11 is operated as a generator, the motor generator 11 is operated by the driving force of the engine 2 to generate power. The electric power generated by the motor generator 11 is input to the inverter converter 12. At this time, the inverter converter 12 functions as a converter. Then, the electric power that has been subjected to the predetermined conversion by the inverter converter 12 is input to and stored in the capacitor power storage device 21 via the step-up / step-down chopper 22. At this time, the step-up / step-down chopper 22 functions as a step-down chopper and steps down the electric power output from the inverter converter 12 to a predetermined voltage and stores it in the capacitor power storage device 21.

  Such torque assist and power generation by the motor generator 11 are applied to the engine 2 on the basis of the speed command (motor command) transmitted from the system controller 1 to the inverter converter 12, the fuel injection amount of the engine 2, the engine speed, and the like. This is performed according to the load. That is, when the load applied to the engine 2 becomes higher than a certain value, the motor generator 11 is operated as a motor, torque assist of the engine 2 is performed, and when the load applied to the engine 2 becomes lower than a certain value, the motor generator 11 is operated. Is operated as a generator, and the power generated by the motor generator 11 is controlled to be stored in the power storage device.

Next, the power storage system unit 20 will be described in detail.
The power storage system unit 20 stores the generated power from the motor generator 11 that operates as a generator and supplies the DC power to the inverter converter 12 and the capacitor power storage device 21 that supplies power to the motor generator 11 that operates as a motor. A step-up / down chopper 22 that performs charge / discharge control on the capacitor power storage device 21, a current / voltage that detects a charge / discharge current of the capacitor power storage device 21, and a capacitor voltage of the capacitor power storage device 21 and an inverter DC voltage of the inverter converter 12. A sensor 25, a constant current control circuit 100 that performs constant current control of charging current to the capacitor power storage device 21, and an equalization control circuit 200 are provided.

  The capacitor power storage device 21 includes a plurality of (two connected in series in this embodiment) electric double layer capacitors (hereinafter referred to as “capacitor modules”) 21 a and 21 b that are connected in a predetermined manner. That is, the equalization control circuit 200 is for equalizing the voltages of the capacitor modules 21a and 21b. Therefore, it is used when the capacitor power storage device 21 has a plurality of capacitor modules, and when the capacitor power storage device 21 is configured by a single capacitor module, the power storage system unit 20 does not use the equalization control circuit 200. It can also be.

As described above, when the motor generator 11 operates as a motor, the step-up / step-down chopper 22 boosts the electric power supplied from the capacitor power storage device 21 to the motor generator 11 and the motor generator 11 operates as a generator. Is for stepping down the electric power generated by the motor generator 11 and storing it in the capacitor power storage device 21. The step-up / step-down chopper 22 receives a charge limiter, a voltage limiter, a charge start command, and a charge stop command from the system controller 1. Such a signal is input.
Further, in the step-up / step-down chopper 22, a charging current command that is a command for the amount of charge to the capacitor power storage device 21 is generated. That is, the step-up / step-down chopper 22 decreases the amount of charge to the capacitor power storage device 21 when the charge current command value decreases, and conversely, the charge to the capacitor power storage device 21 increases when the charge current command value increases. Increase the amount.
The current / voltage sensor 25 detects the current between the step-up / step-down chopper 22 and the capacitor power storage device 21 and detects the capacitor voltage of the capacitor power storage device 21 and the inverter DC voltage of the inverter converter 12. The current value / voltage value detected by the voltage sensor 25 is input to the step-up / step-down chopper 22 and the system controller 1.

In the power storage system unit 20 configured as described above, charge control for controlling the amount of charge to the capacitor power storage device 21 and discharge control for controlling power supplied from the capacitor power storage device 21 are performed.
The charge control for the capacitor power storage device 21 is a constant current charge in which charging to the capacitor power storage device 21 is performed with a substantially constant value (about 60 A) in consideration of the charge / discharge efficiency of the capacitor power storage device 21. The charging current limiter control by the step-up / step-down chopper 22 and the constant current control by the constant current control circuit 100 are performed by two control methods.
Here, the reason why the charging current for the capacitor power storage device 21 is a constant current is as follows. That is, it is to prevent a large current from flowing into the capacitor power storage device 21 instantaneously. In addition, the terminal voltage of each capacitor module 21a / 21b of the capacitor power storage device 21 may become unbalanced due to the charge / discharge amount to the capacitor power storage device 21 or the self-discharge action, which significantly reduces the charge / discharge efficiency. This is because the advantages of the capacitor power storage device 21 with high charge / discharge efficiency cannot be fully utilized.

First, the charging current limiter control by the step-up / step-down chopper 22 will be described.
The charge current limiter control by the step-up / step-down chopper 22 means that the charge / discharge current limiter 55 (see FIG. 2) provided in the step-up / step-down chopper 22 causes the command value of the charge current command generated in the step-up / step-down chopper 22 to fall within a certain range. It is a control to limit. That is, the charging / discharging current limiter 55 is preset with an upper limit value and a lower limit value of the charging current, and the command value input to the charging / discharging current limiter 55 corresponds to a preset charging current value. It is determined whether or not it belongs within the range of the command value. If it belongs, the input value is adopted. If it does not belong, the input value is replaced with the upper limit value (when exceeding) or the lower limit value (when falling) ) Is adopted.

  Thus, by performing the charging current limiter control by the step-up / step-down chopper 22, the charging current to the capacitor power storage device 21 can be set within a certain range (constant current), and the capacitor power storage device 21 having a low internal resistance can be obtained. Since a large current can be prevented from flowing instantaneously, the capacitor power storage device 21 can be prevented from being damaged.

  The charge / discharge current limiter 55 provided in the step-up / step-down chopper 22 performs discharge control for controlling the power supplied from the capacitor power storage device 21. That is, the charge / discharge current limiter 55 that limits the command value of the charge current command generated in the step-up / step-down chopper 22 within a certain range serves to limit the discharge current when power is supplied from the capacitor power storage device 21. In the step-up / step-down chopper 22, discharge current limiter control is also performed as discharge control for limiting the discharge current of the capacitor power storage device 21.

  That is, the charge / discharge current limiter 55 functions as a limiter for the charging current when charging the capacitor power storage device 21, performs constant current charging with the charging current substantially constant, and performs the constant current charging when discharging the capacitor power storage device 21. It works as a limiter and prevents overdischarge of the capacitor power storage device 21 by preventing a large current from being discharged instantly. The range limited by the charge / discharge current limiter 55 can be adjusted. That is, the upper limit value and lower limit value of the charge / discharge current set in the charge / discharge current limiter 55 are variable values.

  In this way, by performing discharge current limiter control by the step-up / step-down chopper 22, when power is supplied from the capacitor power storage device 21, the current flows indefinitely and the capacitor power storage device 21 is brought into an overcurrent state instantaneously. In addition to preventing damage, it is possible to prevent failure of other electronic devices due to overcurrent.

Hereinafter, control of the charging current command based on the inverter DC voltage of the inverter converter 12 (hereinafter referred to as “DC voltage control”) will be described as charge / discharge control performed in the step-up / step-down chopper 22.
In the DC voltage control, as a reference for performing the control, a set voltage (command voltage) Vo as a voltage command value by a voltage command to the step-up / down chopper 22 is compared with an inverter DC voltage Vdc of the inverter converter 12. Done.

That is, in this DC voltage control, when the inverter DC voltage Vdc is lower than the set voltage Vo that is a voltage command value for the step-up / down chopper 22, the step-up / down chopper 22 decreases the command value of the charging current command. Then, the amount of charge to the capacitor power storage device 21 is decreased or the capacitor power storage device 21 is discharged. Conversely, when the inverter DC voltage Vdc is higher than the set voltage Vo, the step-up / step-down chopper 22 The charging current command is controlled so as to increase the command value and increase the charge amount to the capacitor power storage device 21.
In other words, in this DC voltage control, when the inverter DC voltage Vdc> the set voltage Vo, the amount of charge to the capacitor power storage device 21 is increased, and when the inverter DC voltage Vdc <the set voltage Vo, the capacitor power storage device 21 is reached. Control to reduce the amount of charge.

Specifically, the DC voltage control is performed according to the control block diagram shown in FIG.
In the DC voltage control, first, a preset value Yo (for example, a preset value 1500 with respect to the preset voltage Vo = 300) set in advance based on a preset voltage Vo by a voltage command to the step-up / down chopper 22 and an inverter DC voltage Vdc. Is compared with a value Xdc (for example, a value obtained by multiplying the inverter DC voltage Vdc by 10) by the calculation unit 51, and a deviation Yo-Xdc is obtained as a comparison result. In the previous stage of this comparison, in order to balance the set value Yo and the value Xdc corresponding to the inverter DC voltage Vdc, the set value Yo and the value Xdc are converted into constants N1 and Each N2 is multiplied.

  Then, the deviation Yo-Xdc is input to the PI control unit 53. The PI control unit 53 includes a PI controller 53a that performs PI (proportional integration) control calculation based on the deviation Yo-Xdc, and a limiter 53b that limits an output signal from the PI controller 53a within a certain range. ing. By this PI control unit 53, the deviation Yo-Xdc obtained by the calculation unit 51 is calculated and output by the PI controller 53a, and this output passes through the limiter 53b to limit the upper and lower limit values. It is generated as Ypi (hereinafter, charging current command value Ypi). The charging current command value Ypi is a negative (−) value when the capacitor power storage device 21 is charged because the inverter DC voltage Vdc is higher than the set voltage Vo.

  The charging current command value Ypi thus output is added with a correction value, which will be described later, in the calculation unit 54, and the value input by the above-described charging / discharging current limiter 55 is within a preset charging current value range. In the case of belonging, the input value is adopted, and in the case of not belonging, the upper limit value (when exceeding) or the lower limit value (when falling) is adopted instead of the input value. Then, the sign is inverted and output as an output value Ys. This output value Ys becomes the command value of the charging current command in the step-up / step-down chopper 22, and when the output value Ys is a positive (+) value, the inverter DC voltage Vdc is higher than the set voltage Vo. The chopper 22 increases the charge current command value to increase the charge amount of the capacitor power storage device 21. When the chopper 22 has a negative (−) value, the inverter DC voltage Vdc is lower than the set voltage Vo, so The chopper 22 performs control so as to decrease the charge current command value and reduce (discharge) the charge amount to the capacitor power storage device 21.

  Thus, by limiting the charging current command controlled by comparing the set voltage Vo by the voltage command to the step-up / step-down chopper 22 and the inverter DC voltage Vdc within a certain range by the charging / discharging current limiter 55, Since the charge amount of the capacitor power storage device 21 can be controlled according to the inverter DC voltage Vdc, the capacitor power storage device 21 can be appropriately charged / discharged, and the charging current to the capacitor power storage device 21 can be controlled. Is within a certain range (constant current), and the discharge current can be limited.

In the DC voltage control described above, in order to keep the amount of charge to the capacitor power storage device 21 within a certain range and prevent the capacitor power storage device 21 from being overcharged / overdischarged, the command of the charging current command output by the DC voltage control described above is used. Automatic correction of values is performed. That is, in the DC voltage control, the capacitor voltage of the capacitor power storage device 21 (voltage value V _C, hereinafter simply referred to as "capacitor voltage V _C".) The control of the rate of charging of the capacitor power storage device 21 by using (hereinafter, "Charging current control") is performed in conjunction.
That is, in this charging current control, when the capacitor voltage V _C exceeds a preset specified value, the command value of the charging current command is decreased, and when the capacitor voltage V _C falls below the specified value. Then, control is performed so as to increase the command value of the charging current command.

Specifically, it is performed according to the control block diagram shown in FIG.
In the charging current control, firstly, the capacitor voltage V _C of the capacitor power storage device 21, preset the specified value in consideration of the capacitance of the capacitor power storage device 21 (set value V _{N (e.g.,} 53V), hereinafter simply The “capacitor set voltage V _N ” is compared by the calculation unit 57, and a deviation V _C −V _N is obtained as a comparison result. In pre-stage of this comparison, in order to balance the capacitor voltages V _C and capacitor set voltage V _N, the capacitor voltage V _C is the multiplication unit 56, a constant N3 previously set is multiplied.

Then, the deviation V _C −V _N is input to the P control unit 58. The P control unit 58 includes a P controller 58a that performs P (proportional) control calculation based on the deviation V _C −V _N and a limiter 58b that limits an output signal from the P controller 58a within a certain range. I have. By this P control unit 58, the deviation V _C -V _N obtained by the calculation unit 57 is calculated and output by the P controller 58a, and this output passes through the limiter 58b and the upper and lower limit values are limited, and P control is performed. Generated as value Yp. This P control value Yp (hereinafter, correction value Yp) is a correction value for the above-described charging current command value Ypi.

In this charging current control for correcting the charging current command output by the DC voltage control, if the capacitor voltage V _C is lower than the capacitor setting voltage V _N , the current in the charging direction of the capacitor power storage device 21 is increased and the feeding current is suppressed. To prevent overdischarge. Further, if it is higher than capacitor voltage V _C -capacitor setting voltage V _N , the current in the discharging direction of capacitor power storage device 21 is increased, and the charging current is suppressed to prevent overcharging.

  The correction value Yp output in this way is added to the charging current command value Ypi that is output by the DC voltage control in the calculation unit 54, and the addition value Ypi + Yp as the calculation result passes through the charge / discharge current limiter 55. The upper and lower limit values are limited, and the sign is reversed, and this value becomes the final output of the charging current command by the system controller 1.

The manner of correcting the charge current command by such charge current control will be described in correspondence with the control block diagram of FIG. 2 for each of the case where the charge amount to the capacitor power storage device 21 is decreased and the case where it is increased. To do.
First, the case where the charge amount of the capacitor power storage device 21 is decreased will be described.
In this case, the inverter DC voltage Vdc> the set voltage Vo, and the charging current command value Ypi, which is an output by DC voltage control, is a positive (+) value. In this case, when the capacitor voltage V _C is lower than the capacitor set voltage V _N, the correction value Yp output from the charging current control, a negative - a value of (). Since the correction value Yp, which is a negative (−) value, is added to the charging current command value Ypi, which is a positive (+) value, by the computing unit 54, the final output value Ys becomes large and the charging current is increased. The command value increases, the feeding current is suppressed, and overdischarge of the capacitor power storage device 21 is prevented.

Next, a case where the charge amount of the capacitor power storage device 21 is increased will be described.
In this case, the inverter DC voltage Vdc <the set voltage Vo, and the charging current command value Ypi which is an output by the DC voltage control is a negative (−) value. In this case, when the capacitor voltage V _C becomes higher than the capacitor setting voltage V _N , the correction value Yp output from the charging current control becomes a positive (+) value. Since the correction value Yp, which is a positive (+) value, is added to the charging current command value Ypi, which is a negative (−) value, by the calculation unit 54, the final output value Ys is reduced, and the charging current is reduced. The command value decreases, the charging current is suppressed, and the capacitor power storage device 21 is prevented from being overcharged.

Thus, performs charging current control using a capacitor voltage V _C, by performing the automatic correction of the charging current command outputted by the DC voltage control, thereby preventing overcharging and over discharging of the capacitor power storage device 21, Capacitor power storage device 21 having a low internal resistance is protected from overcurrent. Capacitor power storage device 21 with high output responsiveness and high power acceptability is instantly charged with an excessive current, so that capacitor voltage May rise rapidly. To avoid such a situation, the capacitor voltage V _C is, if it reaches the rated voltage of the capacitor power storage device 21 (e.g., 54V), is controlled so as to stop the charging of the capacitor power storage device 21 .
This rated voltage value is a voltage value of the rated voltage that the capacitor power storage device 21 has, and is preset in the system controller 1. That is, the capacitor setting voltage V _N in the above-described charging current control is set slightly lower than this rated voltage value.

That is, since the charging current control is performed so as to prevent the capacitor power storage device 21 from being overcharged, the charging current is suppressed when the capacitor voltage V _C becomes higher than the capacitor setting voltage V _N. If a large current reaches the rated voltage value rises capacitor voltage V _C rapidly, such as by flowing the capacitor power storage device 21, a stop signal is sent from the system controller 1 to the buck-boost chopper 22, thereby buck The chopper 22 stops and the charging of the capacitor power storage device 21 is stopped.

Thus, performs charging current control using a capacitor voltage V _C, performs automatic correction of the charging current command outputted by the DC voltage control by the limiter control buck chopper 22 by the rated voltage value, the capacitor It is possible to prevent overcharge / overdischarge of the power storage device 21, protect the capacitor power storage device 21 having a low internal resistance from overcurrent, and protect the capacitor power storage device 21 from overvoltage. Thereby, since the capacitor power storage device 21 can be prevented from being charged with a large current in a high voltage state, the heat generation and characteristic deterioration of the capacitor power storage device 21 can be suppressed.

Further, as described above, the capacitor voltage V _C reaches the rated voltage value, when stopping the buck chopper 22 by the stop signal from the system controller 1 can also be controlled from the system controller 1 to issue an alarm.
In this case, when the capacitor voltage V _C reaches the rated voltage value, at the same time it sends a stop signal from the system controller 1 to the buck-boost chopper 22, the system controller 1 within or alarm device provided separately, alarm sound (alarm or buzzer ) Or light. This notifies the operator or the like that the capacitor power storage device 21 is in a high voltage state.

Thus, when the capacitor voltage V _C has reached the rated voltage value of the capacitor power storage device 21, a buck-boost chopper 22 is stopped to stop the charging of the capacitor power storage device 21, by notifying by an alarm, An operator or the like can be notified that the capacitor power storage device 21 is in a high voltage state. Thus, the operator or the like can quickly cope with the high voltage state of the capacitor power storage device 21 such as stopping the motor generator 11 as a generator.

Next, constant current control by the constant current control circuit 100 will be described.
The constant current control is control performed by the constant current control circuit 100 so that the current value of the charging current of the capacitor power storage device 21 becomes a substantially constant value (constant current). Hereinafter, the constant current control circuit 100 will be described.

The constant current control circuit 100 is a control circuit for always controlling a current value supplied to the capacitor to a specified value.
Thus, by always setting the current value supplied to the capacitor power storage device 21 to a specified value, an excessive current flows into the capacitor power storage device 21 to prevent the capacitor from being destroyed. is there.

FIG. 3 shows the configuration of the constant current control circuit 100.
The constant current control circuit 100 is connected in parallel to a capacitor power storage device 21 composed of a plurality of capacitor modules 21a and 21b, whereby the input / output terminal of the step-up / down chopper 22 arranged on the load side is Capacitor power storage device 21 and constant current control circuit 100 are connected in parallel.
In FIG. 3, the current of the current value I _MAX is output from the step-up / step-down chopper 22 and is shunted at the terminal 110a, the current of the current value Io is supplied to the capacitor power storage device 21, and the current of the current value I _DS is The constant current is supplied to the constant current control circuit 100 (I _MAX ≈Io + I _DS ).
Also, 101 is a MOSFET as a current control element, so that the current value _{I DS} of the current is diverted at terminal 110a is changed and set according to the value of the gate-source voltage _{V GS} as a control input voltage MOSFET101 It has become. The terminal 110 a is a terminal arranged between the plus terminal of the step-up / down chopper 22 and the plus terminal of the capacitor power storage device 21.
A control voltage SV is input from the system controller 1 (see FIG. 1).
Reference numeral 102 denotes a first inverting amplifier. The first inverting amplifier 102 receives the divided voltage Va of the control voltage SV and the voltage Vb at the terminal 110b. The terminal 110b is a terminal arranged between the minus terminal of the step-up / down chopper 22 and the minus terminal of the capacitor power storage device 21.
Reference numeral 103 denotes a shunt resistor as a constant voltage element connected in series to the capacitor power storage device 21. The voltage Vb is determined by the shunt resistor 103 and the current value Io of the current flowing through the capacitor power storage device 21. Become. Here, the reason why the shunt resistor 103 (resistance value r) is used is to reduce variation in the current value Io.
Reference numeral 104 denotes a second inverting amplifier. The output voltage V _OP of the first inverting amplifier 102 and the ground voltage are input to the second inverting amplifier 104.
The first inverting amplifier 102 and the second inverting amplifier 104 constitute a voltage comparison circuit between the voltage voltage Vb of the shunt resistor 103 and the control voltage SV (a divided voltage Va). Is the gate-source voltage V _GS which is the control input voltage of the MOSFET 101.

The constant current control circuit 100 performs constant current control as shown in the control flow of FIG.
In this flow, the voltage Vb is set by setting (decreasing or increasing) the control voltage SV input from the system controller 1 to the constant current control circuit 100, and determined by the voltage Vb and the shunt resistor 103. It shows that the current value Io to be set is set to a specified value.
First, the flow in which the current value Io is corrected to the specified value when the current value Io increases from the specified value will be described.
Current value Io increases than the prescribed value, becomes greater than the partial pressure Va of the control voltage SV to the voltage Vb is set (step 401), the output voltage _{V OP} of the first inverting amplifier 102 is decreased (step 402) Then, the gate-source voltage V _GS which is the output of the second inverting amplifier 104 is increased (step 403). As the gate source voltage V _GS rises, the current value I _DS of the current passing through the MOSFET 101 is increased (step 404), and as the current value I _DS increases, the current value Io of the current flowing through the capacitor power storage device 21 is increased. Decreases (step 405).
When the current value Io decreases, the value of the voltage Vb determined by the resistance value of the shunt resistor 103 decreases (step 406), and the divided voltage Va and the voltage Vb determined by the control voltage SV are set to be substantially the same ( Step 407).
As described above, when the current value Io increases from the specified value, the voltage Vb is decreased until it becomes substantially the same as the divided voltage Va, and as a result, the current value Io is corrected to the specified value. Become. That is, the current value Io is set to a specified value.

Similarly, the case where the current value Io is reduced from the specified value will be described. In this case, the voltage Vb is smaller than the divided voltage Va of the set control voltage SV (step 411). As a result, the output voltage V _OP in the first inverting amplifier 102 increases (step 412), and the gate-source voltage V _GS that is the output of the second inverting amplifier 104 decreases (step 413). Then, the current value I _DS of the current passing through the MOSFET 101 is decreased by the decrease of the gate source voltage V _GS (step 414), and the current value Io of the current flowing through the capacitor power storage device 21 is decreased by the decrease of the current value I _DS. Increases (step 415).
When the current value Io increases, the value of the voltage Vb determined by the resistance value of the shunt resistor 103 increases (step 416), and the divided voltage Va and the voltage Vb determined by the control voltage SV are set to be approximately the same ( Step 407).
As described above, when the current value Io decreases from the specified value, the voltage Vb is increased until it becomes substantially the same as the divided voltage Va. As a result, the current value Io is corrected to the specified value. Become. That is, the current value Io is set to a specified value.

As can be seen from the above flow, the current value Io is determined by the set voltage (divided voltage Va) of the control voltage SV. By detecting this voltage Vb and changing the control voltage SV, the current value Io is determined. The current value Io can be controlled.
That is, according to the constant current control circuit 100 of FIG. 3, the current value Io flowing through the capacitor power storage device 21 can be set as a specified value by setting the control voltage SV, and the current value Io is set to the specified value. It is possible to control (control to a constant current).

As described above, the constant current control circuit 100 includes the current control element (MOSFET 101) connected in series between the charging path 110A of the capacitor power storage device 21 and the ground terminal, and the current stabilization element connected in series with the capacitor power storage device 21. (Shunt resistor 103) and a voltage comparison circuit for the voltage of the shunt resistor 103 and the control voltage SV (a divided voltage Va). The output of the voltage comparison circuit is used as the control input voltage (gate source voltage V) of the MOSFET 101. _GS ), the current value Io flowing through the capacitor power storage device 21 can be set as a specified value by setting the control voltage SV, and the current value Io is controlled to the specified value ( Can be controlled to a constant current).
Then, by controlling the value of the current supplied to the capacitor power storage device 21 to always be a specified value, an excessive current flows into each of the capacitor modules 21a and 21b, thereby preventing the capacitor power storage device 21 from being destroyed. it can.
Further, even when overcharge is caused by the step-up / step-down chopper 22, the current of the current value I _DS can be released to the constant current control circuit 100 at the terminal 110 a, and failure of the capacitor power storage device 21 can be prevented.

  Thus, by performing constant current control by the constant current control circuit 100, the charging current to the capacitor power storage device 21 can be made constant, and a large current is instantaneously applied to the capacitor power storage device 21 having a low internal resistance. Since it can prevent flowing in, it can prevent that the capacitor electrical storage apparatus 21 is damaged.

The charge current limiter control by the step-up / step-down chopper 22 and the constant current control by the constant current control circuit 100, which are the two control methods in the charge control for the capacitor power storage device 21 described above, can be controlled simultaneously in parallel. However, it is possible to perform only one of them.
At this time, when charging control for the capacitor power storage device 21 is performed only by charging current limiter control by the step-up / step-down chopper 22, the constant current control circuit 100 is stopped by the system controller 1, or the power storage system unit 20 is fixed. The current control circuit 100 is not provided.
Further, when charging control for the capacitor power storage device 21 is performed only by constant current control by the constant current control circuit 100, the upper limit value and lower limit value of the charging current set in the charge / discharge current limiter 55 in the step-up / down chopper 22 are constant values. The constant current control circuit 100 controls the charging current for the capacitor power storage device 21.

Subsequently, voltage equalization control of the capacitor power storage device 21 will be described.
The voltage equalization control of the capacitor power storage device 21 means that the terminal voltage of each of the plurality of capacitor modules constituting the capacitor power storage device 21 is leveled and equalized when the capacitor power storage device 21 is charged. This is control for equalizing the amount of electricity stored. The voltage equalization control includes circuit control by the equalization control circuit 200 and current limit control performed by limiting the charging current to the capacitor power storage device 21 using the step-up / step-down chopper 22 or the constant current control circuit 100. There are two control methods.

First, the uniform control circuit 200 will be described.
The equal control circuit is a control circuit for equalizing the inter-terminal voltages of the capacitor modules connected in series in the capacitor power storage device 21.
And, in this way, the voltage between terminals of each capacitor module connected in series is equalized, thereby increasing the voltage between terminals of a specific capacitor module and trying to prevent such a problem that the charging efficiency is lowered. Is. This also prevents the occurrence of a problem that the voltage between the terminals of a specific capacitor module exceeds the withstand voltage even when charging and discharging are repeated.

FIG. 5 shows the configuration of the equalization control circuit 200.
The equalization control circuit 200 is configured by providing shunt circuits 200 a and 200 b for the capacitor modules 21 a and 21 b connected in series in the capacitor power storage device 21, respectively.
The shunt circuits 200a and 200b attempt to control the magnitude of the current value Iout of the current input to the capacitor modules 21a and 21b by shunting the current of the current value It at the terminals 120a and 120b, respectively.
As shown in FIG. 5, the capacitor modules 21a and 21b are connected in parallel to the step-up / step-down chopper 22 as the capacitor power storage device 21, and the voltage between the terminals of the step-up / step-down chopper 22 is set as the charging voltage V _MAX. The sum of the inter-terminal voltages of the modules 21a and 21b corresponds to the charging voltage _VMAX .
In addition, it is a desirable state that the voltage between terminals of each capacitor module 21a and 21b becomes uniform.

In FIG. 5, reference numerals 131a and 131b denote resistors having the same resistance value, whereby currents having the same current value Iin are supplied to the terminals 120a and 120b, respectively.
Of the currents shunted at the terminals 120a and 120b, the current of the current value Iout is supplied to the capacitor modules 21a and 21b, and the current of the current value It is shunted to the shunt circuits 200a and 200b.
Here, 132a and 132b are MOSFETs as current control elements, and the magnitude of the current value Iout is determined by the MOSFETs 132a and 132b. The MOSFETs 132a and 132b are connected in parallel to the capacitor modules 21a and 21b.
The gate source voltage V _GS as a control input voltage to the MOSFETs 132a and 132b is an output voltage of the error amplifiers 133a and 133b serving as a voltage comparison circuit, and the gate source voltage V _GS is a reference voltage V _REF and a detection resistor. It is determined by comparison between the divided _{V R} of 134a · 135a · 134b · 135b.
Reference numerals 136a and 136b denote Zener diodes as constant voltage elements, which are connected in parallel to the capacitor modules 21a and 21b. The zener diodes 136a and 136b avoid self-discharge of the capacitor modules 21a and 21b, and avoid overcharging (overvoltage) of the capacitor modules 21a and 21b. In other words, the Zener diodes 136a and 136b have the property of conducting when the voltage is higher than the set voltage, and thus perform the functions of self-discharge prevention and overvoltage prevention.

The shunt circuits 200a and 200b having the above configuration have the same configuration.
Of these, first, when the operation of the shunt circuit 200a, the charging of the capacitor module 21a progresses and the capacitor voltage increases, so that the partial pressure V _R is increased. And, thereby, the output of the error amplifier 133a, i.e., the gate-source voltage _{V GS} increases, the current value of the current flowing through the MOSFET132a It increases. When the current value It increases, the current value Iout of the current shunted to the capacitor module 21a side at the terminal 120a is decreased.
In this way, the increase / decrease of the current value Iout is controlled by the capacitor voltage. When the capacitor voltage is low, that is, when the amount of charge is small, the current value Iout is increased and the battery is quickly charged, so that full charge is achieved. As the capacitor voltage increases as it approaches, the current value Iout decreases, and overcharging is not performed. When the capacitor module 21a is finally fully charged, the current supply to the capacitor module 21a is terminated. In this way, the capacitor voltage is always kept constant.
The above also applies to the operation of the shunt circuit 200b in the capacitor module 21b. That is, when the capacitor power storage device 21 has two or more capacitor modules, a similar shunt circuit is provided in each capacitor module.

Further, in the above charging, particularly when rapid charging is performed, a difference occurs in the voltages of the capacitor modules 21a and 21b. For example, when the capacitor module 21a is fully charged first. There is.
In this case, since current supply to the capacitor module 21a is not performed by the control of the shunt circuit 200a, the capacitor module 21a is not overcharged.
On the other hand, during the control by the shunt circuit 200a, the capacitor module 21b is charged, and the capacitor module 21b reaches a fully charged state.
In addition, as shown in FIG. 5, by providing the diode 220, when the capacitor module 21b is first fully charged, the current flowing to the capacitor module 21b side is supplied to the capacitor module 21a. Good.

As described above, the capacitor modules 21a and 21b that are connected in series in the capacitor power storage device 21 are configured to supply the charge current evenly and to the capacitor modules 21a and 21b. The shunt circuits 200a and 200b for shunting a part of the evenly shunted current are provided, and each of the shunt circuits 200a and 200b includes current control elements (MOSFETs 132a and 132b) connected in parallel to the capacitor modules 21a and 21b. A voltage comparison circuit (error amplifiers 133a and 133b) for comparing the voltage ( _divided voltage V _R ) of the capacitor modules 21a and 21b and the reference voltage V _REF, and a constant voltage element (zener) connected in parallel to the capacitor modules 21a and 21b Diodes 136a and 136b), and The output of the comparator circuit (error amplifier 133a · 133b) is configured to be applied as a control input voltage of the MOSFET132a · 132b (gate-source voltage _{V GS),} the discharge Thus, a current charging path 120A · 120B (current value It) By dividing the current into the path 120C, overcharge is prevented while keeping the capacitor voltage of each of the capacitor modules 21a and 21b constant.
Then, overcharging is prevented, that is, the capacitor voltage is kept lower than the withstand voltage, so that heating, breakage, and failure of the capacitor modules 21a and 21b can be prevented (overcharge). protection).
In addition, since both capacitor modules 21a and 21b are finally fully charged, the capacitor power storage device 21 as a whole maintains a high output density (specified output density) even when charging and discharging are repeated. And can take full advantage of the merits of capacitors, such as high responsiveness.

  As described above, by performing the voltage equalization control of the capacitor power storage device 21 by the equalization control circuit 200, it is possible to suppress variations in the terminal voltage of each capacitor module that are likely to occur when the capacitor power storage device 21 is charged, particularly during rapid charging. Can do. Thereby, the charge amount of each capacitor module can be equalized, charging efficiency can be improved, and heat generation due to overcharging of a certain capacitor module can be suppressed. In addition, since the capacitor voltage of capacitor power storage device 21 can be kept constant, overcharge of capacitor power storage device 21 can be prevented.

Next, of the voltage equalization control of the capacitor power storage device 21, the current limit control performed using the step-up / step-down chopper 22 or the constant current control circuit 100 will be described.
In the current limiting control, when the capacitor power storage device 21 is charged, the capacitor voltage is lower than a certain level with respect to the rated voltage of the capacitor power storage device 21 and the capacitor module with the capacitor power storage device 21 is fully charged. Is a control in which the charging current to the capacitor power storage device 21 is set to a specified small current by the step-up / step-down chopper 22 or the constant current control circuit 100.

  That is, in this current limit control, when a full charge signal output when the capacitor power storage device 21 is in a fully charged state is output from the capacitor power storage device 21, the capacitor voltage of the capacitor power storage device 21 is When the voltage difference with respect to the rated voltage of the capacitor power storage device 21 exceeds a preset specified value (hereinafter referred to as “voltage difference specified value”), the charging current to the capacitor power storage device 21 is increased or decreased. By the chopper 22 or the constant current control circuit 100, a predetermined value (hereinafter referred to as “specified current value”) set in advance is set. Thereafter, when the capacitor voltage reaches the rated voltage, the capacitor power storage device 21 is charged. Stop.

  The full charge signal is a signal output from the capacitor power storage device 21 to the system controller 1 when any one of the capacitor modules of the capacitor power storage device 21 is in a full charge state. It is a signal that is emitted when a state is reached. That is, the fact that the full charge signal is output in a state where the capacitor voltage is lower than the rated voltage by a certain level or more means that there may be a difference (variation) in the charge amount of each capacitor module. In this case, the charging current to the capacitor power storage device 21 is set as the specified current value.

  Specifically, the specified voltage difference value and the specified current value are preset in the system controller 1, and when a full charge signal is output from the capacitor power storage device 21 to the system controller 1, the system controller 1 stores the capacitor power. The capacitor voltage of device 21 and the rated voltage are compared. When the voltage difference of the capacitor voltage with respect to the rated voltage exceeds the voltage difference specified value, the system controller 1 charges the capacitor power storage device 21 with respect to the step-up / step-down chopper 22 or the constant current control circuit 100. A command is sent so that the current becomes the specified current value.

That is, when a state in which a full charge signal is output in a state where the capacitor voltage is lower than the rated voltage occurs, the charging current to the capacitor power storage device 21 is specified by the step-up / down chopper 22 or the constant current control circuit 100. By setting the current value (a small current of about 0.5 A), an excessive charging current does not flow into the capacitor power storage device 21, so that the capacitor voltage does not increase rapidly, and the current flows to the capacitor module with a small amount of charge. Since it flows, the charge amount with respect to each capacitor module can be leveled. As a result, it is possible to equalize the terminal voltages of the capacitor modules.
Then, the capacitor power storage device 21 is charged by the charging current of the specified current value, and when the capacitor voltage reaches the rated voltage, the system controller 1 sends a stop signal to the step-up / down chopper 22 or the constant current control circuit 100, Charging of the capacitor power storage device 21 is stopped.

  Thus, by performing the current limiting control using the step-up / step-down chopper 22 or the constant current control circuit 100, the charge amount of each capacitor module can be equalized, the charging efficiency is improved, and a certain capacitor module is Heat generation due to overcharging can be suppressed. In addition, since the capacitor voltage of capacitor power storage device 21 can be kept constant, overcharge of capacitor power storage device 21 can be prevented.

  This current limiting control is intended to equalize the terminal voltages of the capacitor modules 21a and 21b of the capacitor power storage device 21 by reducing the charging current to the capacitor power storage device 21. Compared with the circuit control by the control circuit 200, it is not suitable for the rapid charging of the capacitor power storage device 21, and is used as a backup application of the circuit control by the equal control circuit 200. For example, after the capacitor modules 21a and 21b of the capacitor power storage device 21 are equalized by the equalization control circuit 200 when the capacitor power storage device 21 is rapidly charged, the current limit control is performed after a certain period of time, and each capacitor Applications such as making each of the modules 21a and 21b fully charged are conceivable.

The charge control and voltage equalization control for the capacitor power storage device 21 described above are, as shown in FIG. 6, a power storage system unit having a fuel cell 29 as a power source for supplying power to the motor generator 11 operating as a motor. 20 can also be performed.
In this case, since the step-up / step-down chopper 22 is not provided, only the constant current control by the constant current control circuit 100 is performed for the charge control for the capacitor power storage device 21. As for the voltage equalization control for the capacitor power storage device 21, only the constant current control circuit 100 is used for limiting the charging current to the capacitor power storage device 21 in the current limit control.

By the way, since the capacitor power storage device 21 in which the charge control and the voltage equalization control as described above are performed does not involve a chemical reaction in charge and discharge, if the terminal voltage (capacitor voltage) is measured, the capacitor power storage device is the rest. The stored amount (remaining capacity) can be accurately estimated from the electrostatic capacity of 21.
Specifically, the storage amount (remaining capacity) Q of the capacitor power storage device 21 is obtained from the capacitor voltage V _C of the capacitor power storage device 21 when the capacitance indicating the ability of the capacitor power storage device 21 to store charges is _C. The storage amount Q of the power storage device 21 is expressed by the following equation (1).
Q = CV _C 2/2 (1)
That is, the storage amount Q of the capacitor power storage device 21 can be grasped from the capacitor voltage V _C of the capacitor power storage device, when the capacitor voltage V _C is the withstand voltage of the capacitor power storage device 21, fully charged capacitor power storage device 21 The state will be shown.

Utilizing such characteristics of the capacitor power storage device 21, in this hybrid system, a map corresponding to the capacitance of the capacitor power storage device 21 (hereinafter referred to as “power storage amount estimation map”) is created in advance, and this power storage amount estimation map Based on this, the amount of power stored in the capacitor power storage device 21 is estimated.
That is, based on the previously measured results, as shown in FIG. 6, the storage amount estimation map representing the relationship between the capacitor voltage V _C and the storage amount Q of the capacitor power storage device 21, depending on the capacitance of the capacitor power storage device 21 may be stored in the system controller 1 creates Te, based on the storage amount estimation map, it is made possible to estimate the storage amount Q from the capacitor voltage V _C.
That is, when using the capacitor power storage device 21 having different capacitances according to the application or the like, or using a plurality of capacitor modules having different capacitances as the capacitor power storage device 21, each capacitance (C1, C2, C3, ...) to create a storage amount estimation map for each estimates the storage amount of the capacitor power storage device 21 by only measuring the capacitor voltage V _C.

  As described above, a map corresponding to the capacitance of the capacitor power storage device 21 is created in advance, and the power storage amount of the capacitor power storage device 21 is estimated based on this map, so that the power storage amount can be accurately estimated. The property of the capacitor power storage device 21 can be fully utilized, and the amount of power stored in the capacitor power storage device 21 according to the electrostatic capacity can be easily estimated by measuring only the capacitor voltage.

Further, the amount of power stored in the capacitor power storage device 21 estimated in this way is displayed on a display unit 14 such as a liquid crystal monitor provided in the operation unit 8 and connected to the system controller 1.
As a display form of the current power storage amount of the capacitor power storage device 21 in the display means 14, a numerical value such as digital display or kilowatt display of what percentage of the total power consumption of the capacitor power storage device 21 is consumed. There are a display and a meter display and a bar display that can visually grasp the remaining amount.
Further, in order to more directly grasp the amount of electricity stored in the capacitor power storage device 21, the current amount of power stored in the capacitor power storage device 21 is converted into a time during which the motor generator 11 can be operated as a motor, and this is converted to the capacitor power storage device 21. We propose a method to display the time as the remaining amount.

  As described above, the display unit 14 connected to the system controller 1 is provided, and the current storage amount of the capacitor storage device 21 is displayed on the display unit 14, so that the operator can easily store the storage amount of the capacitor storage device 21. It becomes possible to grasp. In other words, the property of the capacitor power storage device 21 that can accurately estimate the power storage amount can be fully utilized, and the work machine to which the present hybrid system is applied corresponds to the power storage amount of the capacitor power storage device 21. The operation can be performed.

The figure which shows an example of a structure of the hybrid system which concerns on this invention. Block diagram for a step-up / down chopper. The figure which shows the structure of a constant current control circuit. The figure which shows the control flow of the constant current control by a constant current control circuit. The figure which shows the structure of a uniform control circuit. The figure shown about the structure of the electrical storage system part using the figure fuel cell. The figure which shows the electrical storage amount estimation map of a capacitor electrical storage apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 System controller 2 Engine 11 Motor generator 12 Inverter converter 14 Display means 21 Capacitor power storage device 22 Buck-boost chopper 100 Constant current control circuit 200 Equal control circuit

Claims (9)

Engine, motor for assisting the engine, control means for controlling them, a generator driven by the engine, a capacitor for storing electric power generated from the generator and supplying electric power to the motor A hybrid system comprising: a power storage device; a step-up / step-down chopper for stepping up / down an output voltage of the capacitor power storage device; and an inverter converter interposed between the motor and the step-up / step-down chopper for converting input power to a predetermined value. The step-up / step-down chopper includes a charge / discharge current limiter, and the charge amount to the capacitor power storage device and the discharge from the capacitor power storage device are determined by a charge current command limited within a certain range by the charge / discharge current limiter. A hybrid system characterized by controlling the amount. The step-up / down chopper is:
When the inverter DC voltage of the inverter converter is lower than the voltage command value from the control means, the command value of the charging current command is decreased to reduce the charge amount to the capacitor power storage device, or the capacitor Discharging the electricity storage device,
2. The hybrid according to claim 1, wherein when the inverter DC voltage is higher than the voltage command value, the charge current command value is increased to increase a charge amount to the capacitor power storage device. system. The step-up / down chopper is:
When the capacitor voltage exceeds a preset value, the command value of the charging current command is decreased,
When the capacitor voltage falls below the specified value, increase the command value of the charging current command,
The hybrid system according to claim 2, wherein when the capacitor voltage reaches a rated voltage value, charging of the capacitor power storage device is stopped. Engine, motor for assisting the engine, control means for controlling them, a generator driven by the engine, a capacitor for storing electric power generated from the generator and supplying electric power to the motor A hybrid system comprising a power storage device,
A hybrid system comprising a constant current control circuit that performs constant current control of a charging current to the capacitor power storage device. When the capacitor voltage of the capacitor power storage device reaches the rated voltage value of the capacitor power storage device,
5. The hybrid system according to claim 1, wherein an alarm is transmitted from the controller and charging of the capacitor power storage device is stopped.   5. The capacitor power storage device includes a plurality of capacitor modules connected in a predetermined manner, and further includes an equalization control circuit that equalizes a voltage for each of the plurality of capacitor modules. Hybrid system. The voltage difference between the capacitor voltage of the capacitor power storage device and the rated voltage of the capacitor power storage device when a full charge signal output when the capacitor power storage device is fully charged is output from the capacitor power storage device. Is over the preset value,
The charging current to the capacitor power storage device is set to a predetermined value set in advance, and when the capacitor voltage reaches the rated voltage, charging to the capacitor power storage device is stopped. 4. The hybrid system according to 4. Engine, motor for assisting the engine, control means for controlling them, a generator driven by the engine, a capacitor for storing electric power generated from the generator and supplying electric power to the motor A hybrid system comprising a power storage device,
Based on the results measured in advance, a map representing the relationship between the capacitor voltage of the capacitor power storage device and the storage amount is created according to the capacitance of the capacitor power storage device,
A hybrid system, wherein the storage amount is estimated from the capacitor voltage based on the map.   9. The hybrid system according to claim 8, wherein display means connected to the control means is provided, and the estimated storage amount of the capacitor power storage device is displayed on the display means.

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