JP6735998B1 - Charge/discharge control system and charge/discharge control method - Google Patents

Abstract

A charging/discharging control system for controlling charging/discharging of a storage battery unit, comprising: a power conversion unit that performs power conversion between a power unit, which is a power supply or a load, and a storage battery unit; and a charging/discharging of the storage battery unit by controlling the power conversion unit. A control unit for controlling discharge, and the control unit repeats the following (1) and (2) at predetermined intervals until the output power of the power conversion unit reaches a target output power, (1) The target output power is calculated from the voltage of the power unit, the voltage of the storage battery unit, and the internal resistance of the storage battery unit (2) The output power of the power conversion unit is controlled with the calculated output power as the target value. ..

Description

The present invention relates to a charge/discharge control system and a charge/discharge control method, and is suitable for application to, for example, a charge/discharge control system and a charge/discharge control method for controlling charge/discharge of a storage battery unit.

Storage batteries are used in various industrial fields. A CCCV (Constant Current/Constant Voltage) method is generally used as a charging/discharging method for a storage battery.

In the CCCV system, the charging and discharging electric energy originally possessed by the storage battery cannot be fully utilized, and a charging system that solves this problem is also proposed (see Patent Document 1).

JP, 2013-21792, A

In recent years, in charging/discharging a storage battery, there is an output request (for example, standard, specification) that the time from the start of charging or discharging to the set output is within a predetermined time. However, if the output is performed rapidly, there is a possibility of overshoot. On the other hand, if an attempt is made to prevent overshoot, the output requirement may not be satisfied. Patent Document 1 neither discloses nor suggests such a problem and a method for solving the problem.

The present invention has been made in view of the above points, and it is an object of the present invention to propose a charge/discharge control system or the like that can satisfy an output request without overshooting.

In order to solve such a problem, the present invention is a charge/discharge control system for controlling charge/discharge of a storage battery unit, and a power conversion unit that performs power conversion between a power unit that is a power supply or a load and the storage battery unit. A control unit that controls the power conversion unit to control charging/discharging of the storage battery unit, the control unit until the output power of the power conversion unit reaches a target output power: 1) and (2) are repeated at predetermined intervals, (1) A target output power is calculated from the voltage of the power unit, the voltage of the storage battery unit, and the internal resistance of the storage battery unit (2) Calculation The output power of the power converter is controlled with the output power as a target value.

According to the above configuration, for example, the target value according to the internal resistance of the storage battery unit and the voltage of the storage battery unit is calculated at a predetermined interval, and the output voltage increases toward the target value, so output without overshooting. Can meet the demand.

According to the present invention, a highly reliable charge/discharge control system can be realized. For example, it is possible to satisfy the output requirement without overshooting regardless of the type or deterioration degree of the storage battery.

It is a figure showing an example of composition concerning a charge-and-discharge control system by a 1st embodiment. It is a figure which shows the relationship between duty ratio and output electric power by 1st Embodiment. It is a figure which shows the change of output electric power when changing the duty ratio by 1st Embodiment. It is the figure which expanded the part by which output electric power increased sharply by a 1st embodiment. It is a figure which shows the relationship between the output electric power and time by 1st Embodiment. It is a figure which shows the relationship between the output characteristic of PWM control and the measuring method of the internal resistance of a storage battery part by 1st Embodiment. It is a figure which shows an example of the flowchart which concerns on the optimal control process by 1st Embodiment. It is a figure which shows the relationship between duty ratio and output electric power when the optimal control process by 1st Embodiment is performed. It is a figure showing an example of composition concerning a charge-and-discharge control system by a 1st embodiment. It is a figure showing an example of a flow chart concerning processing based on a charge instruction by a 1st embodiment. It is a figure which shows an example of the flowchart which concerns on the optimal control process at the time of charging by 1st Embodiment. It is an image figure which shows the relationship between the 1st charge operation and 2nd charge operation by 1st Embodiment. It is a figure which shows an example of the flowchart which concerns on the process based on a discharge instruction|command by 1st Embodiment. It is a figure which shows an example of the flowchart which concerns on the optimal control process at the time of discharge by 1st Embodiment. It is an image figure which shows the relationship between the 1st discharge operation and the 2nd discharge operation by 1st Embodiment. It is a figure which shows an example of the flowchart which concerns on the optimal control process by 2nd Embodiment.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

(1) First Embodiment In FIG. 1, reference numeral 100 generally indicates a charge/discharge control system according to the first embodiment. FIG. 1 is a diagram showing an example of a configuration of a charge/discharge control system 100.

In the charge/discharge control system 100, the power conversion unit 120 is connected to the power unit 110. The storage battery unit 140 is connected to the power conversion unit 120 via the interface unit 130 and the like.

The power unit 110 is, for example, a device (power source such as a battery or a commercial power source) that supplies power to the storage battery unit 140, and/or a device (load) that consumes the power of the storage battery unit 140.

The power conversion unit 120 is, for example, a DC (Direct Current)/DC converter, and includes a control unit 121, a switching element 122, a choke coil 123 (reactor coil), and a smoothing capacitor 124. For example, the power conversion unit 120 performs power conversion on the power supplied from the power unit 110 by pulse width modulation (PWM) control.

The control unit 121 is, for example, a computer including a hardware circuit (eg, FPGA (Field-Programmable Gate Array), ASIC (Application Specific Integrated Circuit)), a processor unit, and a memory unit. The control unit 121 controls the switching element 122 (ON/OFF control) from the power (input of a constant voltage) supplied from the power unit 110 to create a constant cycle of ON and OFF of the pulse train, and the ON time width. (Duty ratio) is changed to control (adjust) the power (output power) output by the power converter 120. The relationship between the duty ratio and the output power will be described later with reference to FIG.

The switching element 122 is a semiconductor such as a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), an IGBT (Insulated Gate Bipolor Transistor), and a bipolar transistor.

The interface unit 130 is, for example, an interface that includes an interface such as CHAdeMO (registered trademark) that supports rapid charging, a safety device, a device that releases a relay, and a circuit breaker.

The storage battery unit 140 is a storage battery (secondary battery) such as a lithium ion battery, a lead storage battery, or a nickel hydrogen battery. The storage battery unit 140 may be installed in an EV (Electric Vehicle), a mobile terminal, or the like, or may be installed in a facility such as a power plant or a hospital, and the usage form is not limited.

In the charge/discharge control system 100, the voltage 150 (input voltage V ₁ ) of the power unit 110, the voltage 160 (storage battery voltage V ₂ ) of the storage battery unit 140, and the current 170 (current i) are measured.

The charge/discharge control system 100 is not limited to this. For example, when the power unit 110 is an AC power source and the power conversion unit 120 is a DC/DC converter, an AC (Alternating Current)/DC converter is provided between the power unit 110 and the power conversion unit 120.

FIG. 2 is a diagram showing the relationship between the duty ratio and the output power.

The duty ratio is a value obtained by dividing the pulse widths 201, 202, and 203, which are widths (a period in which the signal is not zero) when the voltage is high (high), by a period 204 which is an interval between the pulses (a period of the signal). is there.

As shown in FIG. 2, a pulse width 201 with a large duty ratio (large duty) has a large output (large output 211). Further, the output of the pulse width 202 having a medium duty ratio (duty) is medium (the output is 212). Further, the pulse width 203 having a small duty ratio (small duty) has a small output (small output 213). That is, the execution voltage indicating the apparent voltage increases as the duty ratio increases. When the pulse is a rectangular wave, the execution voltage is represented by the product of the maximum voltage value and the duty ratio.

Here, the power converter 120 is a DC/DC converter to which PWM control is applied. Therefore, the control unit 121 can control the effective voltage by determining how long the voltage is set to High (duty ratio). In other words, the power converter 120 can change the output voltage (output power) without changing the input voltage.

FIG. 3 is a diagram showing a change in output power (charge power to the storage battery unit 140) when the duty ratio is changed. In the curves 301, 302, and 303 shown in FIG. 3, actually, the power unit 110 having a maximum output of 6 kW and the storage battery units 140 having small, medium, and large internal resistances are connected, and the duty ratio is changed. The output power at that time is measured and plotted.

A curve 301 shows the relationship between the duty ratio and the output power in the storage battery unit 140 having a small internal resistance. A curve 302 shows the relationship between the duty ratio and the output power in the storage battery unit 140 having a medium internal resistance. A curve 303 shows the relationship between the duty ratio and the output power in the storage battery unit 140 having a large internal resistance.

As shown in FIG. 3, it can be seen that when the output power becomes 1.2 KW or more, the output power sharply increases with respect to the duty ratio in the storage battery unit 140 having any internal resistance.

FIG. 4 is an enlarged view of a portion where the output power sharply increases.

As shown in FIG. 4, it can be seen that the portion where the output power sharply increases linearly.

A straight line 401 is a straight line that is a linear approximation of a portion of the curve 301 where the output power sharply increases. The straight line 402 is a straight line that is a linear approximation of a portion of the curve 302 where the output power sharply increases. A straight line 403 is a straight line that is a linear approximation of a portion of the curve 303 where the output power sharply increases.

As shown in FIG. 4, it can be seen that the higher the internal resistance of the storage battery unit 140, the slower the rising speed of the output power.

Here, in the curves 301, 302, 303 (straight lines 401, 402, 403), the factors (control factors) that influence the control of the output power include the switching element 122, the choke coil 123, and the like that configure the power conversion unit 120. In addition, there is an internal resistance of the storage battery unit 140. For example, when the power conversion unit 120 performs feedback control (for example, PID control (Proportional Integral Differential Controller)), the output power of the power conversion unit 120 is the target output power (setting output) when the storage battery unit 140 is charged. It is possible to optimally control until reaching. Regarding the control factor of the power conversion unit 120, a constant used for optimal control can be specified, but the control factor outside the power conversion unit 120 (internal resistance of the storage battery unit 140) varies depending on the type of the storage battery unit 140. When the storage battery unit 140 is newly developed, there is a problem that a constant (internal resistance) cannot be specified, or a constant (internal resistance) must be set in the power conversion unit 120. In addition, even in the same storage battery unit 140, since the internal resistance differs depending on the degree of deterioration, there is the same problem.

In this regard, for example, it is conceivable to perform optimal control using a constant (first internal resistance) of the storage battery unit 140 having a predetermined internal resistance and optimally control another type of storage battery unit 140 using the constant. To be

FIG. 5 is a diagram showing a relationship between output power and time when the storage battery section 140 having different internal resistances is optimally controlled using the first internal resistance.

A curve 501 shows the relationship between the output power and time when optimal control is performed on the storage battery unit 140 having the first internal resistance using the first internal resistance. A curve 502 shows the relationship between the output power and time when optimal control is performed using the first internal resistance for the storage battery unit 140 having the second internal resistance having a resistance value lower than the first internal resistance. A curve 503 shows a relationship between output power and time when optimal control is performed using the first internal resistance for the storage battery unit 140 having the third internal resistance having a resistance value higher than the first internal resistance.

Looking at the curve 501, it can be seen that the output does not overshoot (the output is within the threshold) and the target output power (P _set ) is reached in a short time (optimally controlled). Recognize. Looking at curve 502, it can be seen that the output is overshooting (the output is above the threshold). In this case, an increase in power (overpower) has an adverse effect such as damaging the storage battery unit 140. As can be seen from the curve 503, although the output does not overshoot, it takes time to increase the output power, and it takes time to reach the target output power as compared with the curve 501.

At present, in order to avoid overshoot, the storage battery unit 140 having the lowest internal resistance is used as a reference, so it takes time to reach the target output power. However, even if the internal resistance having the lowest resistance value at the present time is used as a reference, when the storage battery unit 140 having an internal resistance having a lower resistance value is commercialized and connected, the storage battery unit 140 will overshoot. ..

In addition, the policy based on the internal resistance having the lowest resistance value at the present time may not be able to meet an output request in which a time required to reach a target output power is within a predetermined time. For example, in the case of EV, the type of storage battery differs depending on the type of EV, and the internal resistance of the storage battery also differs. Particularly, in the EV charging/discharging device, it is necessary to connect to various EVs, and it is difficult to satisfy the output demands for all EVs.

For this reason, when there are a plurality of types of storage battery units 140, it is necessary to perform control suitable for each storage battery unit 140. In the following, a control method (optimal control that reaches a target output power in a short time without output overshooting) when there are a plurality of types of storage battery units 140 will be mainly described.

Since the control content changes depending on the internal resistance of the storage battery unit 140, first, a method of acquiring the internal resistance of the storage battery unit 140 will be described. As a method of acquiring the internal resistance of the storage battery unit 140, there are a first method of measuring the internal resistance of the storage battery unit 140 and a second method of acquiring the internal resistance of the storage battery unit 140 from an external system. In the present embodiment, the first method will be described, and the second method will be described later in the second embodiment.

As a method of measuring the internal resistance of the storage battery unit 140, a two-terminal measuring method, a four-terminal measuring method, or another measuring method can be adopted. Since the two-terminal measuring method and the four-terminal measuring method are known techniques, other measuring methods will be described in the present embodiment.

When the duty ratio is 100%, the power conversion unit 120 is fully opened, so the internal resistance of the storage battery unit 140 is R, the input voltage is V ₁ , the storage battery voltage is V _{2_n} , the current is i _{100_n} , and the power is P _{100_n} . In that case, the following (formula 1) is established according to Ohm's law. Note that n indicates measurement at a certain time point n.
(V ₁ -V _{2_n} )=i _{100_n} ×R (Equation 1)

Further, the power P _{100 — n} is expressed by the following formula.
P _{100_n} = (V ₁ -V _{2_n} )×i _{100_n} (Equation 2)

Therefore, (Equation 3) is derived from (Equation 1) and (Equation 2).
R=(V ₁ -V _{2_n} ) ² /P _{100_n} ... (Equation 3)

Further, as described above, since the portion where the output power sharply increases is linearly increasing, the relationship between the duty ratio and the output power is approximated as a linear line, and its slope (proportional constant) is Since it is constant, the following (formula 5) is established. Note that A _{_n} and B _{_n} are duty ratios, and Z _{_n} is a duty ratio (output value) at the start of control (see FIG. 6).
(A _{_n} -Z _{_n} ):(B _{_n} -Z _{_n} )=P _{a_n} :P _{b_n} ... (Equation 5)

(Equation 6) is derived from (Equation 5).
Z _{_n} =(P _{b_n}・A _{_n} -P _{a_n}・B _{_n} )/(P _{b_n} -P _{a_n} )... (Equation 6)

Also, the slope of the linear line is (P _{b_n} -P _{a_n} )/(B _{_n} -A _{_n} ), and the intercept is -(slope × Z _{_n} ), so the duty ratio when the storage battery voltage is V 2 _{_n} Is _x and the output power at that time is P _x , the following (Equation 7) is derived.
P _{x_n} =(P _{b_n} -P _{a_n} )/(B _{_n} -A _{_n} )・{x-(P _{b_n}・A _{_n} -P _{a_n}・B _{_n} )/(P _{b_n} -P _{a_n} )}...(Formula 7) )

Therefore, the output power when the duty ratio is 100% is given by the following (Equation 8).
P _{100_n} =(P _{b_n} -P _{a_n} )/(B _{_n} -A _{_n} )×{100-(P _{b_n}・A _{_n} -P _{a_n}・B _{_n} )/(P _{b_n} -P _{a_n} )}...(Equation 8) )

Then, from (Equation 3) and (Equation 8), (Equation 9) is derived as the equation for calculating the internal resistance R of the storage battery unit 140.
R=(V ₁ -V _{2_n} ) ² /[(P _{b_n} -P _{a_n} )/(B _{_n} -A _{_n} )×(100-(P _{b_n}・A _{_n} -P _{a_n}・B _{_n} )/(P _{b_n} -P _{a_n} )}]... (Equation 9)

That is, the internal resistance of the storage battery unit 140 can be calculated by measuring the storage battery voltage and the output power (current) at two points (at the duty ratio _{A_n} and the duty ratio _{B_n} ) in the process of increasing the output power. ..

FIG. 6 is a diagram showing the relationship between the output characteristics of the PWM control and the method of measuring the internal resistance (internal impedance) of the storage battery unit 140.

A dotted line 600 shown in FIG. 6 is a characteristic line showing the output characteristic by the actual PWM control. The solid line is a calculation line, and the calculation line 610 is a calculation line that predicts the relationship between the duty ratio and the output power in the storage battery unit 140 that is the measurement target.

The charge and discharge control system 100, first, the PID control to match the calculated line 610 predicted performed, at elevated course of output power, and output power P _{a_1} when the duty ratio A _{_1,} given from the duty ratio A _{_1} The internal resistance of the storage battery unit 140 is calculated by using (Equation 9) by acquiring the output power P _{b_1} at the duty ratio B _{_1} increased by the interval.

Next, the PID control in the optimum control will be described with reference to FIG. Calculation lines 620 and 630 are calculation lines for PID control (broadly speaking, optimum control).

Since the storage battery voltage changes due to the change in the charging state of the storage battery unit 140, the target value of the output power is reset (the calculation line 620 reaching the new target value 621 is obtained), and the PID control is performed so as to match the calculation line 620. Done. Further, since the storage battery voltage changes due to the change in the charging state of the storage battery unit 140, the target value of the output power is reset (the calculation line 630 reaching the new target value 631 is obtained) and the calculation line 630 is fitted. PID control is performed.

FIG. 7 is a diagram showing an example of a flowchart relating to the optimal control process for measuring the internal resistance of the storage battery unit 140 and performing the PID control.

In step S710, control unit 121 measures (calculates) the internal resistance of storage battery unit 140. For example, the control unit 121, the measurement value when the duty ratio A _{_1} and (current, input voltage and battery voltage), the measurement value when the duty ratio B _{_1} and (current, input voltage and battery voltage), the above ( The internal resistance of the storage battery unit 140 is calculated using Equation 9) and.

First, the control unit 121 predicts a calculation line used for initial PID control. For example, the control unit 121 sets the maximum output power P _{100_1} (maximum output) and the initial output value Z _{_1} (for example, the storage battery voltage/input voltage when the power unit 110 and the storage battery unit 140 are connected). The connecting straight line is the calculation line used for the initial PID control.

Then, the control unit 121 raises the output power along the predicted calculation line by the PID control.

Here, as shown in FIG. 3, in most cases, the output suddenly rises linearly at 15% or more of the maximum output. Therefore, for example, the control unit 121, when the output power is 15% or more, the inside of the storage battery unit 140. Start measuring resistance. More specifically, the control unit 121 includes a battery voltage when the duty ratio A _{_1} the output power is at 15% or more (the output power P _{a_1),} the duty ratio B was increased by a predetermined amount from the duty ratio A _{_1} The storage battery voltage (output power P _{b_1} ) at _{_1} is acquired. Note that the increasing rate of the duty ratio is set in advance at a rate at which the optimum control is performed by the predetermined storage battery unit 140, for example.

In step S720, the control unit 121 calculates the maximum output power P _{100_n} at the present time using the internal resistance calculated in step S710, the measured storage battery voltage P _{b_n−1,} and the following (formula 10). , Set the calculated P _{100_n} as the target value. For example, the control unit 121 _obtains a new calculation line from the two points of the target value P _{100_n} and the output value Z _{_n by setting} the output value Z _{_n} to V _{2_n-1} /V ₁ . As a rule of thumb, the output value Z _{_n} is the storage battery voltage V _{2_n-1} / input voltage V ₁ when charging, and (input voltage V _{1 -storage} battery voltage V _{2_n-1} ) / input voltage when discharging. V ₁ is preferable.

Here, from (Equation 3), (Equation 10) is derived as the equation for calculating the target value P _{100 — n} for the increase in output power.
P _{100_n} = (V ₁ -V _{2_n} ) ² /R (Equation 10)

In step S730, control unit 121 charges storage battery unit 140. For example, the control unit 121 shifts (increases) the output power to a new calculation line, performs PID control according to the new calculation line to increase the output power, and charges the storage battery unit 140.

In step S740, the control unit 121 determines whether the output power has reached the target output power (set output). If the control unit 121 determines that it has arrived, it ends the optimal control process, and if it determines that it has not reached, it moves the process to step S720. Note that step S740 may be configured to determine whether or not the output power has reached a predetermined value or more. In this case, PID control is performed from the predetermined value to the set output.

Here, the description has been mainly given to the case of charging, but the same applies to the case of discharging.

By the above processing, optimal control (the output power reaches the set output in a short time without overshooting the output power) while avoiding the influence of any factor such as the type of the storage battery unit 140 and the change in the storage battery voltage. it can.

FIG. 8 is a diagram showing the relationship between the duty ratio and the output power when the optimum control process is performed.

As shown in FIG. 8, the output power increases from the output value Z ₁ along the calculation line 810, and based on the measured value when the duty ratio is A _{_1} and the measured value when B _{_1 in} the increasing process. The internal resistance of the storage battery unit 140 is measured. Then, the target value P _{100_2} is calculated, a new calculation line 820 is obtained, and the output power increases along the calculation line 820. Further, at a control period (measurement cycle), the duty ratio is output power measured when the B _{_2,} the target value P _{100_3} is calculated, a new calculation line 830 is determined, the output power along the calculation line 830 Becomes higher, and the output power reaches the set output.

Next, an example of a case (charge/discharge control system 900) in which the charge/discharge control system 100 is applied to EV charging/discharging will be described with reference to FIGS. 9 to 15.

FIG. 9 is a diagram showing an example of the configuration of the charge/discharge control system 900.

In the charge/discharge control system 900, the power conversion unit 920 is connected to the house 910. The EV 930 is connected to the power conversion unit 920. Note that other configurations such as the interface unit are omitted.

In the charge/discharge control system 900, the storage battery 931 mounted on the EV 930 is charged/discharged.

When the storage battery 931 is charged, a solar power generation system, a commercial power supply, or the like provided in the house 910 serves as a power source, and power generated by the solar power generation system and system power of the commercial power supply is supplied to the storage battery 931. For example, the user performs a predetermined operation of a device related to charging/discharging (connection of a charging/discharging connector (not shown), pressing of a charging start button displayed on a smartphone, a personal computer, a V2H (Vehicle to Home) device, a timer, etc. Charging to the storage battery 931 can be started by setting (eg, setting). When a predetermined operation of the device related to charging/discharging is performed, a charging instruction is transmitted from the device to the control unit 921. The process based on the charging instruction will be described later with reference to FIGS. 10 and 11.

On the other hand, when the storage battery 931 is discharged, an electric device, a storage battery, or the like provided in the house 910 becomes a load, and the generated power of the photovoltaic power generation system, the system power of the commercial power supply, and the electric power due to the discharge of the storage battery 931 become the load of the house 910. Is supplied to. For example, the user can start discharging from the storage battery 931 by performing a predetermined operation of the device related to charging/discharging. When a predetermined operation of the device relating to charging/discharging is performed, a discharging instruction is transmitted from the device to the control unit 921. The processing based on the discharge instruction will be described later with reference to FIGS. 13 and 14.

Like the power conversion unit 120, the power conversion unit 920 includes a control unit 921, a choke coil 922, switching elements 923 and 924, a smoothing capacitor 925, and a current sensor 926. The current sensor 926 detects the output current of the house 910 when the storage battery 931 is charged, or detects the output current of the storage battery 931 when the storage battery 931 is discharged. Illustration of the voltage sensor and the like is omitted.

Further, the power conversion unit 920 is connected to the network 940 and can acquire various information (for example, information on IoT (Internet of Things) devices) via the network 940. When the charge/discharge connector is connected, the power conversion unit 920 and the storage battery 931 of the EV 930 are connected, and the control unit 921 of the power conversion unit 920 and the control unit (not shown) of the EV 930 communicate with each other. Connected as possible.

In addition, the power conversion unit 920 is communicably connected to the EV 930 by wire or wirelessly. The power conversion unit 920 may be communicatively connected to the EV 930 via the network 940, may be communicatively connected to the EV 930 without the network 940, and may be communicatively connected to the EV 930. It does not have to be done.

FIG. 10 is a diagram showing an example of a flowchart relating to processing based on a charging instruction.

In step S1010, the control unit 921 determines whether the date has been changed from the previous charging. The control unit 921 moves the process to step S1030 when it is determined that it has been changed, and moves the process to step S1020 when it is determined that it has not been changed.

In step S1020, control unit 921 determines whether EV 930 has been changed from the previous charging. The control unit 921 moves the process to step S1030 when it is determined that it has been changed, and moves the process to step S1070 when it is determined that it has not been changed.

In step S1030, control unit 921 determines whether or not the charge command value transmitted from EV 930 is sufficiently large (whether or not the charge amount is larger than a predetermined threshold value). The control unit 921 moves the process to step S1040 when it is determined to be large, and moves the process to step S1070 when it is determined to be not large.

In step S1040, control unit 921 determines whether or not power is being received from house 910 (system). When determining that the power is being received, the control unit 921 moves the process to step S1050, and when determining that the power is not being received, the control unit 921 moves the process to step S1070.

In step S1050, the control unit 921 determines whether or not the discharge lower limit power (discharge lower limit voltage) of the EV 930 is equal to or higher (whether or not charging is performed during overdischarge). If it is determined that the above is the case, the control unit 921 moves the process to step S1060, and if it is determined that the above is not the case, the process moves to step S1070.

In step S1060, the control unit 921 performs optimal control processing during charging, and moves the processing to step S1070. The optimal control process during charging will be described later with reference to FIG.

In step S1070, the control unit 921 performs normal charging (charging by the existing charging method).

FIG. 11 is a diagram showing an example of a flowchart relating to the optimum control process during charging.

In step S1110, the control unit 921 increases the output power to 15% or more of the maximum output, and executes (starts) the first charging operation. For example, the control unit 921 controls the output power along the calculation line. The duty ratio at the start of the first charging operation is referred to as the first duty ratio.

In step S1120, the control unit 921 measures the electric power P _{a_1} (PWM width, electric power) at the first duty ratio A _{_1} . For example, the control unit 921 acquires the input voltage V ₁ of the house 910 and the storage battery voltage V ₂ of the storage battery 931 measured by a voltage sensor (not shown), and the current measured by the current sensor 926.

In step S1130, control unit 921 implements (starts) the second charging operation. For example, the control unit 921 continues the first charging operation until the duty ratio increases by a predetermined amount, and then starts the second charging operation. In the second charging operation, the control unit 921 increases the output power so as to shift to the next calculation line (to reach the duty ratio and the output power at the start of the next control cycle).

In step S1140, the control unit 921 measures the electric power P _{a_2} (PWM width, electric power) at the second duty ratio _{A_2} at the start of the second charging operation (at the end of the first charging operation). For example, the control unit 921 acquires the input voltage V ₁ of the house 910 and the storage battery voltage V ₂ of the storage battery 931 measured by a voltage sensor (not shown), and the current measured by the current sensor 926.

In step S1150, control unit 921 calculates the internal resistance (internal impedance) of storage battery 931. For example, the control unit 921 performs the calculation using the measurement value acquired in step S1120, the measurement value acquired in step S1140, and the above-described (formula 9).

In step S1160, control unit 921 reflects the calculation result in charging PID control, and ends the charging optimization control process.

FIG. 12 is an image diagram showing the relationship between the first charging operation and the second charging operation.

In FIG. 12, the measurement value at the start of the first charging operation and the measurement value at the start of the second charging operation are acquired while performing the first charging operation, and the measurement value of the storage battery 931 is acquired while performing the second charging operation. The internal resistance is calculated, the calculation line 1203 is obtained from the next target value 1201 and the output value 1202, and after shifting to the calculation line 1203 by the second charging operation, output again along the calculation line 1203 by the first charging operation. The power is shown to be PID controlled.

FIG. 13 is a diagram showing an example of a flowchart relating to processing based on a discharge instruction.

In step S1310, the control unit 921 determines whether the date has been changed since the last discharge. The control unit 921 moves the process to step S1330 when it is determined that it has been changed, and moves the process to step S1320 when it is determined that it has not been changed.

In step S1320, control unit 921 determines whether EV 930 has been changed from the previous discharge. The control unit 921 moves the process to step S1330 when it is determined that it has been changed, and moves the process to step S1370 when it is determined that it has not been changed.

In step S1330, control unit 921 determines whether the discharge command value transmitted from EV 930 is sufficiently large (whether the discharge amount is larger than a predetermined threshold value). The control unit 921 moves the process to step S1340 when it is determined to be large, and moves the process to step S1370 when determined to be not large.

In step S1340, control unit 921 determines whether power is being received from storage battery 931. The control unit 921 moves the process to step S1350 when it is determined that the power is being received, and moves the process to step S1370 when it is determined that the power is not being received.

In step S1350, the control unit 921 determines whether or not the discharge lower limit power (discharge lower limit voltage) of the EV 930 or more (whether overdischarge occurs or not). If it is determined that the above is the case, the control unit 921 moves the process to step S1360, and if it is determined that the above is not the case, the process moves to step S1370.

In step S1360, the control unit 921 performs optimal control processing during discharging, and moves the processing to step S1370. The optimum control process during discharging will be described later with reference to FIG.

In step S1370, the control unit 921 performs normal discharge (discharge by the existing discharge method).

FIG. 14 is a diagram showing an example of a flowchart relating to the optimal control process during discharging.

In step S1410, the control unit 921 raises the output power to 15% or more of the maximum output, and carries out (starts) the first discharge operation. For example, the control unit 921 controls the output power along the calculation line. The duty ratio at the start of the first discharge operation is called the first duty ratio.

In step S1420, control unit 921 measures electric power P _{a_1} (PWM width, electric power) at first duty ratio A _{_1} . For example, the control unit 921 acquires the input voltage V ₁ of the storage battery 931 and the load voltage V _{2 of the} house 910 measured by a voltage sensor (not shown), and the current measured by the current sensor 926.

In step S1430, the control unit 921 implements (starts) the second discharge operation. For example, the control unit 921 continues the first discharge operation until the duty ratio increases by a predetermined amount, and then starts the second discharge operation. In the second discharge operation, the control unit 921 increases the output power so as to shift to the next calculation line (to reach the duty ratio and the output power at the start of the next control cycle).

In step S1440, the control unit 921 measures the power P _{a_2} (PWM width, power) at the second duty ratio _{A_2} at the start of the second discharge operation (at the end of the first discharge operation). For example, the control unit 921 acquires the input voltage V ₁ of the storage battery 931 and the load voltage V _{2 of the} house 910 measured by a voltage sensor (not shown), and the current measured by the current sensor 926.

In step S1450, control unit 921 calculates the internal resistance (internal impedance) of storage battery 931. For example, the control unit 921 performs the calculation using the measurement value acquired in step S1420, the measurement value acquired in step S1440, and the above-described (formula 9).

In step S1460, the control unit 921 reflects the calculation result in the discharge PID control, and ends the discharge optimization control process.

FIG. 15 is an image diagram showing the relationship between the first discharge operation and the second discharge operation.

In FIG. 15, the measurement value at the start of the first discharge operation and the measurement value at the start of the second discharge operation are acquired while performing the first discharge operation, and the storage battery 931 of the storage battery 931 is acquired while performing the second discharge operation. The internal resistance is calculated, the calculation line 1503 is obtained from the next target value 1501 and the output value 1502, and after shifting to the calculation line 1503 by the second discharge operation, the output is output along the calculation line 1503 again by the first discharge operation. The power is shown to be PID controlled.

According to the present embodiment, it is possible to reach the target power output in a short time without overshooting.

(2) Second Embodiment This embodiment is different from the first embodiment in that the internal resistance of the storage battery unit 140 is acquired from an external system. In the present embodiment, points different from the first embodiment will be mainly described.

FIG. 16 is a diagram showing an example of a flowchart relating to the optimum control process for acquiring the internal resistance of the storage battery unit 140 from an external system and performing PID control.

In step S1610, control unit 121 acquires the internal resistance of storage battery unit 140 from an external system.

For example, the control unit 121 acquires the internal resistance of the storage battery unit 140 measured by the EV from the EV equipped with the storage battery unit 140. In addition, for example, the control unit 121 acquires the internal resistance of the storage battery unit 140 via a network from a storage device that stores the internal resistance of the storage battery unit 140 that is measured by an EV equipped with the storage battery unit 140.

The internal resistance of the storage battery unit 140 acquired from the external system is a measurement value measured at the site where charging/discharging is performed.

According to the present embodiment, even if power conversion unit 120 (control unit 121) does not have the function of measuring the internal resistance of storage battery unit 140, the target power output can be reached in a short time without overshooting. it can.

(3) Other Embodiments In the above embodiments, the case where the present invention is applied to the charge/discharge control system has been described, but the present invention is not limited to this, and various other systems, The present invention can be widely applied to devices (EV charging/discharging devices, industrial charging/discharging devices such as power plants, hospitals, buildings, and other charging/discharging devices), methods, and programs.

Further, in the above-described embodiment, the case where the internal resistance of the storage battery unit 140 is measured only once has been described, but the present invention is not limited to this, and the internal resistance of the storage battery unit 140 is measured a plurality of times (for example, every control cycle). The internal resistance may be measured and the latest value or average value may be used. For example, in the example of FIG. 8, the control unit 121, using the measurement value when the measured value and the duty ratio B _{_2} when the duty ratio A _{_2} and the above-mentioned (9), the internal resistance of the battery unit 140 To measure. Further, for example, the internal resistance of the storage battery unit 140 is measured using the measured value at the duty ratio _{A_3} , the measured value at the duty ratio _{B_3} , and the above-mentioned (Equation 9).

Further, in the above-described embodiment, the case has been described in which the straight line connecting the maximum output power P _{100_1} and the initial output value Z _{_1} is used as the calculation line used for the initial PID control, but the present invention is not limited to this. Instead, a straight line connecting the maximum output power P _{100_1} and the point where the output power generally starts to rapidly increase (eg, duty ratio 65.2%, output power 1.2 kW) is used for the initial PID control. May be

Further, in the above-described embodiment, the case where the calculation line is obtained from the two points of the target value (P _{100 — n} ) and the output value Z — _n has been described, but the present invention is not limited to this, and the calculation line toward the target value is It can be appropriately adopted. For example, the calculation line may be obtained from two points, the target value (P _{100 — n} ) and the point (B — _n , P _{b — 1} ) at the start of the second charging operation (second discharging operation). Further, for example, the calculation line may be obtained by moving the calculation line in the initial _stage in parallel and passing through the target value (P _{100 — n} ).

Further, in the above-described embodiment, for the output value Z _{_n} , when charging, the storage battery voltage V _{2_n-1} / input voltage V ₁ , and when discharging, (input voltage V _{1 -storage} battery voltage V _{2_n-1} ) Although the case where the input voltage is V ₁ has been described, the present invention is not limited to this, and other values that can be calculated from the storage battery voltage and the input voltage, or a predetermined value (for example, 30%) can be set. Good. Although the processing time can be shortened by setting the initial output value _{Z_n} , the present invention is also applicable to the case where the initial output value _{Z_n} is started from "0%". ..

Further, in the above-described embodiment, the pulse width modulation control is described as an example, but the present invention is not limited to this, and other modulation methods may be used.

In addition, in the above-described embodiment, the “memory unit” is one or more memories, and typically may be a main storage device. At least one memory in the memory unit may be a volatile memory or a non-volatile memory.

Further, in the above-described embodiment, the “processor unit” is one or more processors. The at least one processor is typically a microprocessor such as a CPU (Central Processing Unit), but may be another type of processor such as a GPU (Graphics Processing Unit). At least one processor may be single-core or multi-core. The at least one processor may be a processor in a broad sense such as a hardware circuit (eg, FPGA (Field-Programmable Gate Array) or ASIC (Application Specific Integrated Circuit)) that performs a part or all of the processing.

Further, the function of the processor unit may be realized by a “program”. The program is executed by the processor unit to perform the predetermined processing while appropriately using the memory unit and/or the interface unit (for example, communication port). Further, the processor unit may include a hardware circuit (eg, FPGA (Field-Programmable Gate Array) or ASIC (Application Specific Integrated Circuit)) that performs a part or all of the processing. The program may be installed in a device such as a computer from the program source. The program source may be, for example, a program distribution server or a computer-readable recording medium (for example, a non-transitory recording medium). Further, two or more programs may be realized as one program, or one program may be realized as two or more programs.

Further, in the above description, information such as programs, tables, and data for realizing each function is recorded in a memory, a hard disk, a storage device such as SSD (Solid State Drive), or an IC card, an SD card, a DVD, or the like. Can be placed on media.

The present invention has the following characteristic configurations, for example.

A charging/discharging control system (for example, a charging/discharging control system 100, a charging/discharging control system 900) that controls charging/discharging of a storage battery unit (for example, the storage battery unit 140, a storage battery 931), which is a power supply or a load (for example, a power unit). , The power unit 110, the house 910) and the storage battery unit for converting power between the storage battery unit (for example, the power conversion unit 120, the power conversion unit 920) and the power conversion unit to control the storage battery unit. And a control unit (for example, a control unit 121 and a control unit 921) that controls charging/discharging, and the control unit controls the output power of the power conversion unit to be a target output power (for example, a set output, P _set ). Until reaching, the following (1) and (2) are set to a predetermined interval (for example, a constant duty ratio interval, a constant time interval, a predetermined mode (the interval is gradually decreased so that the interval gradually increases). (1) The voltage of the electric power unit and the voltage of the storage battery unit are repeated at a set duty ratio interval, a time interval set in a predetermined manner, etc.). The target output power is calculated from the voltage and the internal resistance of the storage battery unit (for example, calculated from (Equation 1) and (Equation 2), calculated from (Equation 3), and calculated from (Equation 10) (2) ) The output power of the power converter is controlled with the calculated output power as a target value (for example, the first charging operation and the second charging operation are performed, the first discharging operation and the second discharging operation are performed, and the target value (P _{100_n} ) And the point ( _{B_n} , _{Pb_1} ) at the start of the second charging operation (second discharging operation) along the calculation line obtained from the two points).

According to the above configuration, for example, the target value according to the internal resistance of the storage battery unit and the voltage of the storage battery unit is calculated at a predetermined interval, and the output voltage increases toward the target value, so output without overshooting. Can meet the demand.

The power conversion unit performs power conversion by pulse width modulation control (PWM control), and the control unit performs feedback during charging so that the output power of the power conversion unit follows the calculation line obtained by (3) below. Performing control (for example, PID control, proportional control, derivative control, integral control, etc.) (3) Using the following formula (A), the output value of the pulse width at the start of the calculation line is calculated and calculated. It is characterized in that a calculation line is obtained from the output value and the target value.
Z=V ₂ /V ₁・・・Formula (A)
However,
Z: Output value
V ₁ : voltage of the power section,
V ₂ : The voltage of the storage battery section.

According to the above configuration, at the time of charging, it is controlled so that the target value can be reached in a short time from the output power at the present time, based on the voltage of the storage battery at the present time, so for example, in a short time without overshooting. The desired power output can be reached.

The power conversion unit performs power conversion by pulse width modulation control, and during charging, the control unit measures the voltage of the power unit and the storage battery measured before the start of the process of repeating the above (1) and (2). The output value is calculated using the voltage of the unit and the following formula (A), and the calculated output value is used as the duty ratio at the start of the above process.
Z=V ₂ /V ₁・・・Formula (A)
However,
Z: Output value
V ₁ : voltage of the power section,
V ₂ : The voltage of the storage battery section.

According to the above configuration, the time required to reach the set duty ratio can be shortened by setting the duty ratio at the start of processing during charging.

The contents of the charging described above are the same for the discharging.

The control unit measures an internal resistance of the storage battery unit.

According to the above configuration, for example, since the internal resistance of the storage battery unit is measured, even when the present invention is applied to a charging/discharging device that is connected to various types of storage batteries, it is possible to achieve a target in a short time without overshooting. Power output can be reached.

The control unit measures the internal resistance of the storage battery unit in the process of increasing the output power of the power conversion unit to a target output power.

According to the above configuration, for example, the internal resistance of the storage battery unit can be measured without stopping or delaying the rise of the output power, and thus the time for obtaining the internal resistance of the storage battery unit is reduced. be able to.

The control unit acquires the internal resistance of the storage battery unit from an external system.

According to the above configuration, for example, since the internal resistance of the storage battery unit is acquired, even when the present invention is applied to a charging/discharging device connected to various types of storage batteries, it is possible to achieve a target in a short time without overshooting. Power output can be reached. Further, by utilizing the internal resistance of the storage battery unit measured by the external system, it is not necessary to provide the power conversion unit (control unit) with a configuration for measuring the internal resistance of the storage battery unit.

In addition, the configurations described above may be appropriately changed, rearranged, combined, or omitted without departing from the scope of the present invention.

According to the above configuration, a highly reliable charge/discharge control system can be realized.

100... Charge/discharge control system, 110... Power unit, 120... Power conversion unit, 130... Interface unit, 140... Storage battery unit.

Claims (9)

A charging/discharging control system for controlling charging/discharging of a storage battery unit,
A power conversion unit that performs power conversion between a power unit that is a power source or a load and the storage battery unit,
A control unit that controls the power conversion unit to control charging and discharging of the storage battery unit,
Equipped with
The control unit repeats the following (1) and (2) at predetermined intervals until the output power of the power conversion unit reaches a target output power,
(1) A target output power is calculated from the voltage of the power unit, the voltage of the storage battery unit, and the internal resistance of the storage battery unit. (2) Output of the power conversion unit with the calculated output power as a target value. A charge/discharge control system characterized by controlling electric power. The power conversion unit performs power conversion by pulse width modulation control,
At the time of charging, the control unit performs feedback control so that the output power of the power conversion unit follows the calculation line obtained by (3) below.
(3) The output value of the pulse width at the start of the calculation line is calculated using the following formula (A), and the calculation line is obtained from the calculated output value and the target value. Charge and discharge control system.
Z=V ₂ /V ₁・・・Formula (A)
However,
Z: Output value
V ₁ : voltage of the power section,
V ₂ : The voltage of the storage battery section. The power conversion unit performs power conversion by pulse width modulation control,
When charging, the control unit outputs the voltage of the power unit and the voltage of the storage battery unit measured before the start of the process of repeating (1) and (2), and using the following formula (A). Calculating a value and using the calculated output value as the duty ratio at the start of the process,
The charge/discharge control system according to claim 1, wherein:
Z=V ₂ /V ₁・・・Formula (A)
However,
Z: Output value
V ₁ : voltage of the power section,
V ₂ : The voltage of the storage battery section. The power conversion unit performs power conversion by pulse width modulation control,
At the time of discharging, the control unit performs feedback control such that the output power of the power conversion unit follows the calculation line obtained by (4) below.
(4) The output value of the pulse width at the start of the calculation line is calculated using the following formula (B), and the calculation line is obtained from the calculated output value and the target value. Charge and discharge control system.
Z=(V ₁ -V ₂ )/V ₁ ...Equation (B)
However,
Z: Output value
V ₁ : voltage of the power section,
V ₂ : The voltage of the storage battery section. The power conversion unit performs power conversion by pulse width modulation control,
At the time of discharging, the control unit outputs the voltage of the power unit and the voltage of the storage battery unit measured before the start of the process of repeating (1) and (2), and using the following formula (B). Calculating a value and using the calculated output value as the duty ratio at the start of the process,
The charge/discharge control system according to claim 1, wherein:
Z=(V ₁ -V ₂ )/V ₁ ...Equation (B)
However,
Z: Output value
V ₁ : voltage of the power section,
V ₂ : The voltage of the storage battery section. The control unit measures an internal resistance of the storage battery unit,
The charge/discharge control system according to claim 1, wherein: The control unit measures the internal resistance of the storage battery unit in the process of increasing the output power of the power conversion unit to a target output power,
The charge/discharge control system according to claim 6, wherein. The control unit acquires the internal resistance of the storage battery unit from an external system,
The charge/discharge control system according to claim 1, wherein: A charging/discharging control method in a charging/discharging control system for controlling charging/discharging of a storage battery part,
The charge/discharge control system includes a power conversion unit that performs power conversion between a power unit that is a power supply or a load and the storage battery unit, and a control unit that controls the power conversion unit to control charge/discharge of the storage battery unit. And,
The control unit, until the output power of the power conversion unit reaches the target output power,
(1) A first step of calculating a target output power from the voltage of the power unit, the voltage of the storage battery unit, and the internal resistance of the storage battery unit, and (2) the calculated output power as a target value. The second step of controlling the output power of the power conversion unit is repeated at a predetermined interval.

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