Charge / discharge control device, charge / discharge control system, and charge / discharge control method

Abstract

To suppress fluctuation of a DC bus voltage within a predetermined range, and to control a charging rate of a power storage device without requiring switching of a control rule.SOLUTION: The charge / discharge control device 30 includes a discharging voltage controller 31 that outputs a discharging target current value for increasing the bus voltage when the bus voltage is lower than a predetermined discharging start voltage value, a charging voltage controller 32 that outputs a charging target current value for decreasing the bus voltage when the bus voltage is higher than a predetermined charging start voltage value, a charging rate controller 33 that outputs a charging rate target current value for keeping the charging rate of the power storage device within a predetermined range, a current command value setting unit 34 that calculates a current command value using the discharging target current value, the charging target current value, and the charging rate target current value, and a control signal generator 38 that generates a control signal for the power converter based on the current value of the power storage device and the current command value.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a charge / discharge control device, a charge / discharge control system, and a charge / discharge control method. [Background technology]

[0002] Conventionally, systems have been proposed that make effective use of regenerative power in DC systems with regenerative loads. In such systems, a power storage device is provided for the purposes of suppressing voltage fluctuations on the DC bus and shaving peak demand. The power storage device must maintain a charge rate within a predetermined range, and various control methods have been proposed.

[0003] For example, Patent Document 1 discloses a system that has a control block that controls a DC bus voltage and a control block that controls the charging rate of a power storage device, and that selectively switches between these blocks.

[0004] Furthermore, Patent Document 2 discloses a system that adjusts the charge rate of a storage battery within a certain range by lowering the set value of the DC bus voltage at which charging starts when the charge rate of the storage battery drops, and by raising the set value of the DC bus voltage at which discharging starts when the charge rate of the storage battery increases. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 4238190 [Patent Document 2] Patent No. 5377538 Summary of the Invention [Problem to be solved by the invention]

[0006] In the system of Patent Document 1, the control block that controls the DC bus voltage and the control block that controls the charge rate of the power storage device are selected and operated, so it is not possible to simultaneously adjust the charge rate of the power storage device and the fluctuation of the DC bus voltage, which poses a problem in response to an instantaneous change in the DC bus voltage.

[0007] Furthermore, in the system of Patent Document 2, the charging rate of the storage device is adjusted by varying the set value of the DC bus voltage, which causes a problem in that the voltage fluctuation suppression range of the DC bus varies depending on the charging rate of the storage device.

[0008] The present disclosure has been made in consideration of the above circumstances, and aims to provide a charge / discharge control device, a charge / discharge control system, and a charge / discharge control method that can suppress fluctuations in DC bus voltage within a predetermined range and control the charging rate of a storage device without the need to switch control laws. [Means for solving the problem]

[0009] One aspect of the present disclosure is a charge / discharge control device that controls the charging and discharging of a power storage device by controlling a power converter connected between the power storage device and a DC bus, and includes: a discharge voltage control unit that outputs a discharge target current value for increasing the voltage value of the DC bus when the voltage value of the DC bus is lower than a predetermined discharge start voltage value; a charge voltage control unit that outputs a charge target current value for decreasing the voltage value of the DC bus when the voltage value of the DC bus is higher than a predetermined charge start voltage value; a charging rate control unit that outputs a charging rate target current value for keeping the charging rate of the power storage device within a predetermined range; a current command value setting unit that calculates a current command value using the discharge target current value, the charge target current value, and the charging rate target current value; and a control signal generation unit that generates a control signal for the power converter based on the current value of the power storage device and the current command value.

[0010] One aspect of the present disclosure is a charge / discharge control system including a power converter connected between a power storage device and a DC bus, and the charge / discharge control device described above.

[0011] One aspect of the present disclosure is a mechanical parking device equipped with the above-described charge / discharge control system.

[0012] One aspect of the present disclosure is a charge / discharge control method for controlling the charging / discharging of a power storage device by controlling a power converter connected between the power storage device and a DC bus, wherein the charge / discharge control method is performed by a computer, and includes a process of outputting a discharge target current value for increasing the voltage value of the DC bus when the voltage value of the DC bus is lower than a predetermined discharge start voltage value; a process of outputting a charge target current value for decreasing the voltage value of the DC bus when the voltage value of the DC bus is higher than a predetermined charge start voltage value; a process of outputting a charge rate target current value for keeping the charge rate of the power storage device within a predetermined range; a process of calculating a current command value using the discharge target current value, the charge target current value, and the charge rate target current value; and a process of generating a control signal for the power converter based on the current value of the power storage device and the current command value.

[0013] One aspect of the present disclosure is a program for causing a computer to function as the charge / discharge control device. [Effects of the Invention]

[0014] According to the charge / discharge control device, charge / discharge control system, and charge / discharge control method disclosed herein, fluctuations in the DC bus voltage can be suppressed within a predetermined range, and the charging rate of the storage device can be controlled without the need to switch control laws. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a diagram showing an example of a configuration related to power management of a mechanical parking device to which a charge / discharge control system according to a first embodiment of the present disclosure is applied. FIG. [Figure 2] 1 is a diagram showing a configuration of a charge / discharge control system according to a first embodiment of the present disclosure. [Figure 3] 2 is a functional block diagram illustrating an example of functions provided in the charge / discharge control device according to the first embodiment of the present disclosure. FIG. [Figure 4] FIG. 2 is a diagram illustrating an example of the configuration of a discharge voltage control unit according to the first embodiment of the present disclosure. [Figure 5] FIG. 2 is a diagram illustrating a configuration example of a charging voltage control unit according to the first embodiment of the present disclosure. [Figure 6] FIG. 2 is a diagram illustrating a configuration example of a current control unit according to the first embodiment of the present disclosure. [Figure 7] FIG. 6 is a functional block diagram showing an example of functions provided in a charge / discharge control device according to a second embodiment of the present disclosure. [Figure 8] FIG. 10 is a diagram illustrating an example of the configuration of a correction value calculation unit according to a second embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0016] [First embodiment] Hereinafter, a charge / discharge control device, a charge / discharge control system, and a charge / discharge control method according to a first embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is a diagram showing an example of a configuration related to power management of a mechanical parking device 1 to which a charge / discharge control system 10 according to a first embodiment of the present disclosure is applied.

[0017] As shown in Fig. 1, a direct current bus (DC bus) 2 is installed in a mechanical parking device 1, and a load 3 and a power storage device 4 can be connected to this DC bus 2. In Fig. 1, the number of connected loads 3 and power storage devices 4 is an example and is not limited to this.

[0018] The load 3 is, for example, a drive device for driving various mechanical mechanisms. Examples include a drive motor for raising and lowering a vehicle transport means such as a pallet, a door opening / closing motor for opening and closing an entrance door or gate, and a rotation motor for rotating a turntable. The load 3 is connected to the DC bus 2 via a power converter 6. The power converter 6 is, for example, an inverter device. The load 3 includes, for example, a regenerative load. As a result, when the load 3 is powered, power is supplied from the DC bus 2 to the load 3, and when the load 3 is regenerated, power is supplied from the load 3 to the DC bus 2.

[0019] The power storage device 4 is connected to the DC bus 2 via a charge / discharge control system 10. The power storage device 4 is a chargeable / dischargeable secondary battery, and examples thereof include a battery mounted on an electric vehicle parked in the mechanical parking device 1, and a storage battery installed in the mechanical parking device 1. Details of the charge / discharge control system 10 will be described later.

[0020] The DC bus 2 is connected to an electric power system 100 via a power converter 7, a transformer 8, etc. The power converter 7 is, for example, an inverter device for grid interconnection.

[0021] Each charge / discharge control system 10 is connected to an EMS (Energy Management System) 40 via a communication network. The EMS 40 is connected to a VPP gateway PC 50 that manages a VPP (Virtual Power Plant) via the communication network.

[0022] The VPP gateway PC50 is, for example, a management system that connects multiple small-scale power generation and storage facilities via a network and performs integrated management. The VPP gateway PC50 performs integrated management of, for example, adjusting the energy supply and demand of the power network under its management, stabilizing the power supply through peak cutting, and buying and selling of power in the power market.

[0023] The EMS 40 generates a power command value Pref for controlling charging and discharging according to a predetermined algorithm using information related to energy supply and demand provided by the VPP gateway PC 50, the energy supply and demand state of the mechanical parking device 1, and battery states such as the charging rate of the power storage device 4, and outputs the generated power command value Pref to the charge and discharge control system 10. It should be noted that known technologies can be appropriately adopted for the VPP gateway PC 50 and the EMS 40.

[0024] 2 is a diagram showing the configuration of a charge / discharge control system 10 according to this embodiment. As shown in FIG. 2, the charge / discharge control system 10 includes a power converter 20 and a charge / discharge control device 30.

[0025] The power converter 20 is connected between the power storage device 4 and the DC bus 2. The power converter 20 is, for example, a bidirectional chopper device, and includes a reactor 21, a switching unit 22, and a capacitor 23. The switching unit 22 includes, for example, switching elements 24 and 25 connected in series. The switching elements 24 and 25 are, for example, power elements such as IGBTs, and have backflow prevention diodes connected in anti-parallel. The charging and discharging of the electricity storage device 4 is controlled by controlling the on / off of the switching elements 24, 25 by the charge / discharge control device 30. The power converter 20 is not limited to the configuration shown in Fig. 2 as long as it is configured to be able to control the charging and discharging of the electricity storage device 4. The power converter 20 can be configured as appropriate using a known power converter configuration.

[0026] The power converter 20 is also provided with a voltage sensor (battery voltage detection unit) 26 that detects the battery voltage, which is the voltage between the terminals of the storage device 4, a current sensor (battery current detection unit) 27 that detects the battery current input / output from the storage device 4 to the power converter 20, a voltage sensor 28 that detects the voltage of the DC bus 2, and a current sensor 29 that detects the current of the DC bus 2. The voltage detection value by the voltage sensor 26 (hereinafter referred to as "battery voltage VB"), the current detection value by the current sensor 27 (hereinafter referred to as "battery current IB"), the voltage detection value by the voltage sensor 28 (hereinafter referred to as "bus voltage VC"), and the current detection value by the current sensor 29 (hereinafter referred to as "bus current IL") are output to the charge / discharge control device 30. In this embodiment, the current sensor 29 can be omitted.

[0027] The charge / discharge control device 30 generates gate signals Pgate and Ngate, which are control signals for the power converter 20, based on the battery voltage VB, the battery current IB, the bus voltage (voltage value of the DC bus) VC, and the power command value Pref acquired from the EMS 40 (see FIG. 1). Then, the on / off of the switching element 24 is controlled based on the gate signal Pgate, and the on / off of the switching element 25 is controlled based on the gate signal Ngate, thereby controlling the charging and discharging of the power storage device 4.

[0028] The charge / discharge control device 30 is realized by a computer such as a PLC (Programmable Logic Controller). The charge / discharge control device 30 includes, for example, a CPU (Central Processing Unit: Processor), a main memory, and a secondary storage. The charge / discharge control device 30 may further include a communication unit for transmitting and receiving information to and from other devices. One or more CPUs may be provided, and they may cooperate with each other to perform processing.

[0029] FIG. 3 is a functional block diagram showing an example of functions of the charge / discharge control device 30. A series of processes for realizing the various functions shown in FIG. 3 is stored in the form of a program in a secondary storage device, for example. The CPU reads this program into the main storage device and executes information processing and arithmetic processing to realize the various functions. The program may be pre-installed in the secondary storage device, provided in a state stored in a computer-readable storage medium, or distributed via wired or wireless communication means. Examples of computer-readable storage media include magnetic disks, magneto-optical disks, CD-ROMs, DVD-ROMs, and semiconductor memories.

[0030] As shown in FIG. 3, the charge / discharge control device 30 includes a discharge voltage control section 31, a charge voltage control section 32, a charging rate control section 33, a current command value setting section , and a control signal generating section .

[0031] When the bus voltage VC is lower than a predetermined discharge start voltage value VCDref, the discharge voltage control unit 31 outputs a discharge target current value IBDref for increasing the bus voltage VC. Fig. 4 is a diagram showing an example of the configuration of the discharge voltage control unit 31. As shown in Fig. 4, the discharge voltage control unit 31 includes, for example, a subtraction unit 41, a proportional control unit 42, an integral control unit 43, a limiter 44, an addition unit 45, and a limiter 46.

[0032] The subtraction unit 41 calculates the deviation between the discharge start voltage value VCDref and the bus voltage VC. The proportional control unit 42 performs proportional control on the deviation output from the subtraction unit 41 . The integral control unit 43 performs integral control on the deviation output from the subtraction unit 41 . The limiter 44 adjusts the output from the integral control unit 43 so that it falls within a predetermined upper and lower limit range. For example, the lower limit value IBDmin of the limiter 44 is set to zero. The upper limit value IBDmax of the limiter 44 is set appropriately according to the operation of the DC bus 2 (for example, +100 A).

[0033] The adder 45 adds the output from the proportional control unit 42 and the output from the limiter 44 to calculate the discharge target current value IBDref. Here, a limiter 44 is provided downstream of the integral control unit 43, whereas no limiter is provided downstream of the proportional control unit 42. In other words, the output of the proportional control unit 42 is output to the adder 45 without passing through a limiter.

[0034] The limiter 46 adjusts the discharge target current value IBDref output from the adder 45 so that it falls within a predetermined upper and lower limit range, and outputs the adjusted value. For example, the upper and lower limit values ​​of the limiter 46 may be set to the same values ​​as those of the limiter 44.

[0035] When the bus voltage VC is higher than a predetermined charging start voltage value VCCref, the charging voltage control unit 32 outputs a charging target current value IBCref for reducing the bus voltage VC.

[0036] Fig. 5 is a diagram showing an example of the configuration of the charging voltage control unit 32. As shown in Fig. 5, the charging voltage control unit 32 includes, for example, a subtraction unit 51, a proportional control unit 52, an integral control unit 53, a limiter 54, an addition unit 55, and a limiter 56. The subtraction unit 51 calculates the deviation between the charging start voltage value VCCref and the bus voltage VC. The proportional control unit 52 performs proportional control on the deviation output from the subtraction unit 51 . The integral control unit 53 performs integral control on the deviation output from the subtraction unit 51 . The limiter 54 adjusts the output from the integral control unit 53 so that it falls within a predetermined upper and lower limit range. For example, the lower limit value IBCmin of the limiter 54 is set to zero. The upper limit value IBCmax of the limiter 54 is set appropriately depending on the operation of the DC bus 2. Note that when the discharge current is expressed as a positive value, the charge current is expressed as a negative value. In other words, the upper limit value IBCmax is set as a negative number (for example, −100 A).

[0037] The adder 55 adds the output from the proportional control unit 52 and the output from the limiter 54 to calculate the charging target current value IBCref. Here, a limiter 54 is provided after the integral control unit 53, whereas no limiter is provided after the proportional control unit 52. In other words, the output of the proportional control unit 52 is output to the adder 55 without passing through a limiter.

[0038] The limiter 56 adjusts the output IBCref from the adder 55 so that it falls within a predetermined upper and lower limit range, and outputs the adjusted value. For example, the upper and lower limit values ​​of the limiter 56 may be set to the same values ​​as those of the limiter 54.

[0039] The charging rate control unit 33 outputs a charging rate target current value IBEref for keeping the charging rate of the power storage device 4 within a predetermined range. For example, the charging rate control unit 33 includes a division unit 61 that divides the power command value Pref by the battery voltage VB, and a lamp control unit 62 that outputs a charging rate target current value IBEref obtained by changing the output from the division unit 61 at a predetermined rate. Here, the power command value Pref is, for example, a command value given by the EMS 40 shown in Fig. 1. For example, the EMS 40 outputs the power command value Pref for charging (negative value) when the charging rate SOC of the entire power storage device provided in the mechanical parking device 1 is lower than the target value, and for discharging (positive value) when the charging rate SOC is higher.

[0040] The current command value setting unit 34 calculates a current command value IBref using the discharge target current value IBDref output from the discharge voltage control unit 31, the charge target current value IBCref output from the charge voltage control unit 32, and the charging rate target current value IBEref output from the charging rate control unit 33. Specifically, the current command value setting unit 34 includes an adder 71 and a limiter 72.

[0041] The adder 71 calculates a current command value IBref by adding the discharge target current value IBDref, the charge target current value IBCref, and the charging rate target current value IBEref. The limiter 72 adjusts the current command value IBref output from the adder 71 so that it falls within a predetermined upper and lower limit range, and outputs the adjusted value. For example, the lower limit value IBmin of the limiter 72 is set to IBCmax (e.g., −100 A), and the upper limit value IBmax is set to IBDmax (e.g., +100 A).

[0042] The control signal generating unit 38 generates a control signal for the power converter 20 based on the battery current IB and the current command value IBref. The control signal generating section 38 includes, for example, a current control section 35 and a gate signal generating section 36 .

[0043] The current control unit 35 calculates a power converter low-voltage side voltage command value VCHref based on the current command value IBref output from the current command value setting unit 34 and the battery current IB, to bring the battery current IB closer to the current command value IBref.

[0044] Fig. 6 is a diagram showing an example of the configuration of the current control unit 35. As shown in Fig. 6, the current control unit 35 includes, for example, a subtraction unit 81, a proportional control unit 82, an integral control unit 83, a limiter 84, an addition unit 85, and a limiter 86.

[0045] A subtraction unit 81 calculates the deviation between the current command value IBref and the battery current IB. The proportional control unit 82 performs proportional control on the deviation output from the subtraction unit 81 . The integral control unit 83 performs integral control on the deviation output from the subtraction unit 81 . The limiter 84 adjusts the output from the integral control unit 83 so that it falls within a predetermined upper and lower limit range, and outputs the adjusted output. For example, the lower limit VCmin and upper limit VCmax of the limiter 84 are set appropriately depending on the operation. For example, the lower limit VCmin is set to 300 V, and the upper limit VCmax is set to 350.

[0046] The adder 85 adds the output from the proportional control unit 82 and the output from the limiter 84 to calculate and output the power converter low-voltage side voltage command value VCHref. Here, limiter 84 is provided downstream of integral control unit 83, whereas no limiter is provided downstream of proportional control unit 82. In other words, the output of proportional control unit 82 is output to adder 85 without passing through a limiter.

[0047] The limiter 86 adjusts the power converter low-voltage side voltage command value VCHref output from the adder 85 so that it falls within a predetermined upper and lower limit range, and outputs the adjusted value. For example, the lower limit value VCmin and upper limit value VCmax of the limiter 86 can be set appropriately depending on the operation. For example, they may be set to the same values ​​as those of the limiter 84 described above.

[0048] The gate signal generation unit 36 ​​generates gate signals (PWM signals) Pgate and Ngate based on the power converter low-voltage side voltage command value VCHref output from the current control unit 35. For example, the gate signal generation unit 36 ​​divides the power converter low-voltage side voltage command value VCHref by the bus voltage VC and compares this output value (VCHref / VC) with a carrier wave of a predetermined carrier frequency (e.g., a triangular wave) to generate gate signals Pgate and Ngate for controlling the switching elements 24 and 25. The on / off of the switching elements 24 and 25 is then controlled based on the gate signals Pgate and Ngate. Note that control of the switching elements of the chopper circuit by PWM control is a well-known technique, and therefore a detailed description thereof will be omitted here.

[0049] Next, the operation of the charge / discharge control system 10 according to the present embodiment will be described.

[0050] [Steady state] For example, in the mechanical parking device 1, when the supply and demand of power are balanced, the bus voltage VC is equal to or higher than the discharge start voltage value VCDref and equal to or lower than the charge start command VCCref.

[0051] In such a steady state, in the discharge voltage control unit 31, the output of the subtraction unit 41 takes a negative value, and therefore the discharge target current value IBDref output from the addition unit 45 also takes a negative value. This discharge target current value IBDref is adjusted by the limiter 46 to within a predetermined upper and lower limit range (for example, 0 A to 100 A), so that it becomes zero and does not contribute to charging or discharging.

[0052] Similarly, in the charging voltage control unit 32, the output of the subtraction unit 51 is a positive value, and therefore the charging target current value IBCref output from the addition unit 55 is a positive value. This charging target current value IBCref is adjusted by the limiter 56 to fall within a predetermined upper and lower limit range (for example, −100 A to 0 A), so that it becomes zero and does not contribute to charging or discharging.

[0053] On the other hand, the charging rate control unit 33 divides the power command value Pref given by the EMS 40 by the battery voltage VB, and outputs the charging rate target current value IBEref by changing this output at a predetermined rate.

[0054] Therefore, in the steady state, the current command value IBref is generated based on the charging rate target current value IBEref output from the charging rate control unit 33, and charging and discharging of the power storage device 4 are controlled based on this. In other words, in the steady state, charging and discharging of the power storage device 4 are controlled based on the power command value Pref given by the EMS 40.

[0055] [Bus voltage VC is below discharge start voltage VCDref] For example, in the mechanical parking device 1, if the balance between power supply and demand is disrupted and the load demand is greater than the amount of power supplied to the DC bus 2, the bus voltage VC will be equal to or lower than the discharge start voltage value VCDref. Here, the EMS 40 grasps the supply and demand balance on the DC bus 2 and provides the charge / discharge control system 10 with a power command value Pref that maintains the balance. However, responsiveness is poor, due to delays caused by communication, etc. Therefore, if the balance between power supply and demand is disrupted due to a sudden load fluctuation, it is necessary to respond quickly to this fluctuation and maintain the bus voltage VC within a normal range.

[0056] In such a supply and demand state, in the discharge voltage control unit 31, the output of the subtraction unit 41 is a positive value, and therefore the discharge target current value IBDref output from the addition unit 45 is also a positive value. The larger the deviation between the discharge start voltage value VCDref and the bus voltage VC, the larger the value of this discharge target current value IBDref becomes, and it is adjusted within the upper and lower limit range of the limiter 46 (for example, 0 A to 100 A).

[0057] On the other hand, in the charging voltage control unit 32, the output of the subtraction unit 51 is a positive value, and therefore the charging target current value IBCref output from the addition unit 55 is a positive value. This charging target current value IBCref is adjusted by the limiter 56 to within a predetermined upper and lower limit range (for example, −100 A to 0 A), so that it becomes zero and does not contribute to charging or discharging.

[0058] In the charging rate control unit 33, the power command value Pref given from the EMS 40 is divided by the battery voltage VB, and this output is changed at a predetermined rate to output a charging rate target current value IBEref.

[0059] As a result, when the bus voltage VC is equal to or lower than the discharge start voltage value VCDref, a current command value IBref is generated based on the charging rate target current value IBEref, which is based on the power command value Pref, and the discharge target current value IBDref, which compensates for the excessive load demand, and charging and discharging of the storage device 4 is controlled based on this current command value IBref. In this way, by adding the discharge target current value IBDref to the current command value IBref, discharging is performed to compensate for the excessive load demand. This makes it possible to suppress a drop in bus voltage due to excessive load demand and maintain the bus voltage VC within a predetermined range. As a result, it is possible to prevent the bus voltage VC from dropping below the normal range and causing the load equipment to shut down due to low voltage protection.

[0060] [Bus voltage VC is equal to or greater than the charging start voltage VCDref] For example, in the mechanical parking device 1, when the balance between power supply and demand is disrupted and the load demand is less than the amount of power supplied to the DC bus 2, the bus voltage VC becomes equal to or greater than the charge start voltage value VCDref. Here, the EMS 40 grasps the supply and demand balance on the DC bus 2 and provides the charge / discharge control system 10 with a power command value Pref that maintains the balance. However, responsiveness is poor due to communication delays and other factors. Therefore, when the balance between power supply and demand is disrupted due to a sudden load fluctuation or the like, it is necessary to respond quickly to this fluctuation and maintain the bus voltage VC within a normal range.

[0061] In such a supply-demand state, in the discharge voltage control unit 31, the output of the subtraction unit 41 takes a negative value, and therefore the discharge target current value IBDref output from the addition unit 45 also takes a negative value. This discharge target current value IBDref is adjusted by the limiter 46 to fall within a predetermined upper and lower limit range (for example, 0 A to +100 A), so that it becomes zero and does not contribute to charging or discharging.

[0062] On the other hand, in the charging voltage control unit 32, the output of the subtraction unit 51 is a negative value, and therefore the charging target current value IBCref output from the addition unit 55 is also a negative value. The charging target current value IBCref takes a larger value as the deviation between the charging start voltage value VCCref and the bus voltage VC increases, and is adjusted within the upper and lower limit range of the limiter 56 (-100 A to 0 A).

[0063] In the charging rate control unit 33, the power command value Pref given from the EMS 40 is divided by the battery voltage VB, and this output is changed at a predetermined rate to output a charging rate target current value IBEref.

[0064] As a result, when the bus voltage VC is equal to or higher than the charge start voltage value VCCref, a current command value IBref is generated based on the charging rate target current value IBEref, which is based on the power command value Pref, and the charging target current value IBCref, which compensates for the excessive power supply amount, and charging and discharging of the power storage device 4 is controlled based on this current command value IBref. In this way, by adding the charging target current value IBCref to the current command value IBref, charging is performed to compensate for the excessive power supply amount. This makes it possible to suppress an increase in bus voltage due to excessive power supply amount, and to maintain the bus voltage VC within the normal range. As a result, it is possible to prevent the bus voltage VC from rising above the normal range and causing the load device to shut down due to overvoltage protection.

[0065] As described above, according to this embodiment, the charge / discharge control device 30 includes a discharge voltage control unit 31 that outputs a discharge target current value IBDref for increasing the bus voltage VC, which is the voltage value of the DC bus 2, when the bus voltage VC is lower than a predetermined discharge start voltage value VCDref; a charge voltage control unit 32 that outputs a charge target current value IBCref for decreasing the bus voltage VC when the bus voltage VC is higher than a predetermined charge start voltage value VCCref; a charging rate control unit 33 that outputs a charging rate target current value IBEref for keeping the charging rate of the storage device 4 within a predetermined range; a current command value setting unit 34 that calculates a current command value IBref using the discharge target current value IBDref, the charging target current value IBCref, and the charging rate target current value IBEref; and a control signal generation unit 38 that generates a control signal for the power converter 20 based on the battery current IB, which is the current value of the storage device 4, and the current command value IBref.

[0066] In this way, the current command value IBref is calculated using the discharge target current value IBDref, the charge target current value IBCref, and the charging rate target current value IBEref. This eliminates the need to switch control laws, as described in Patent Document 1, and makes it possible to eliminate response delays and the like caused by the switching laws.

[0067] Furthermore, the power command value Pref provided by the EMS 40 is subject to delays due to communication delays and the like. That is, even if the balance between power supply and demand in the mechanical parking device 1 is disrupted and the DC bus 2 transiently rises or falls, it is difficult for the power command value Pref to respond immediately to this fluctuation. In this regard, according to the present embodiment, the discharge voltage control unit 31 and the charge voltage control unit 32 output current target values ​​according to the voltage fluctuation of the DC bus 2, so that it is possible to respond quickly to the voltage fluctuation of the DC bus 2 and suppress the bus voltage VC within a normal range.

[0068] Furthermore, in the discharge voltage control unit 31 and the charge voltage control unit 32, no limiter is provided on the output side of the proportional control units 42 and 52, and the outputs of the proportional control units 42 and 52 are input to the adders 45 and 55 without going through a limiter. This makes it possible to avoid the output from the proportional control units 42 and 52 being suppressed by a limiter. This makes it possible to improve the response performance to fluctuations in the bus voltage VC.

[0069] Second Embodiment Next, a charge / discharge control device, a charge / discharge control system, and a charge / discharge control method according to a second embodiment of the present disclosure will be described.

[0070] In the first embodiment described above, the charging rate control unit 33 obtains the charging rate target current value IBEref by dividing the power command value Pref provided by the EMS 40 by the battery voltage VB. At this time, the power (VB×IB) discharged from the power storage device 4 becomes close to the power command value Pref, but the power (VC×IL) on the DC bus 2 side becomes smaller by the amount of loss in the power converter 20. Therefore, in this embodiment, taking this loss into consideration, a function is further provided to correct the power command value Pref when the deviation between the power command value Pref and the power on the DC bus 2 side exceeds a predetermined range. Hereinafter, the same components as those in the first embodiment will be assigned the same reference numerals and their description will be omitted, and differences will be mainly described.

[0071] 7 is a functional block diagram showing an example of functions of the charge / discharge control device 30a according to this embodiment. In FIG. 7, the control signal generating unit 38, which is arranged after the current command value setting unit 34, is not shown.

[0072] As shown in FIG. 7, the charging rate control unit 33a according to this embodiment includes a lamp control unit 63, a power command correction unit 64, and a division unit 65.

[0073] The lamp control unit 63 changes the power command value Pref given from the EMS 40 at a predetermined rate and outputs it. The power command correction unit 64 corrects the power command value output from the lamp control unit 63 using the actual power value P of the DC bus 2. The power command correction unit 64 includes, for example, an actual power value calculation unit 91, a correction value calculation unit 92, and an addition unit 93.

[0074] The actual power value calculation unit 91 calculates the actual power value P by multiplying the bus voltage VC and the bus current IL together. The correction value calculation unit 92 calculates a correction value using the actual power value P and the power command value Pref output from the lamp control unit 63. Fig. 8 is a diagram showing an example of the configuration of the correction value calculation unit 92. As shown in Fig. 8, the correction value calculation unit 92 includes, for example, a subtraction unit 111, a proportional control unit 112, an integral control unit 113, a limiter 114, an addition unit 115, and a limiter 116.

[0075] The subtraction unit 111 calculates the deviation between the power command value Pref output from the lamp control unit 63 and the actual power value P. The proportional control unit 112 performs proportional control on the deviation output from the subtraction unit 111 . The integral control unit 113 performs integral control on the deviation output from the subtraction unit 111 . The limiter 114 adjusts the output from the integral control unit 113 so that it falls within a predetermined upper and lower limit range. The upper and lower limit values ​​of the limiter 114 are set appropriately depending on the operation of the DC bus 2. The adder 115 calculates the correction value Pc by adding the output from the proportional control unit 112 and the output from the limiter 114 . The limiter 116 adjusts the correction value Pc so that it falls within a predetermined upper and lower limit range and outputs it.

[0076] The correction value Pc calculated by the correction value calculation unit 92 is output to the adder 93 and added to the power command value Pref output from the lamp control unit 63. As a result, the power command value Pref from the EMS 40 is corrected using the actual power value of the DC bus 2. The corrected power command value Pref' is output to the division unit 65. The division unit 65 calculates the charging rate target current value IBEref' by dividing the power command value Pref' by the battery voltage VB. In this way, in this embodiment, the charging rate target current value IBEref' is calculated using the corrected power command value Pref' and the battery voltage VB.

[0077] In this embodiment, the corrected power command value Pref′ is used to set the upper limit values ​​of the limiters 44, 46, 54, and 56 provided in the discharge voltage control unit 31 and the charge voltage control unit 32, and the upper and lower limit values ​​of the limiter 72 provided in the current command value setting unit 34.

[0078] For example, the charge / discharge control device 30a includes upper limit setting units 110 and 120. The upper limit value setting unit 110 sets the discharging upper limit value IBDmax using the power value PWDref corresponding to the lower limit SOC of the power storage device 4 and the power command value Pref′.

[0079] For example, the upper limit setting unit 110 includes an adder 131 and a divider 132. The adder 131 adds the power value PWDref and the power command value Pref′. The divider 132 divides the output from the adder 131 by the battery voltage VB to set the discharging upper limit value IBDmax. This discharging upper limit value IBDmax is used as the upper limit value for the limiters 44, 46 and limiter 72.

[0080] The upper limit setting unit 120 sets the charging upper limit IBCmax using the power value PWCref corresponding to the upper limit SOC of the power storage device 4 and the power command value Pref′.

[0081] For example, the upper limit value setting unit 120 includes an adder 121 and a divider 122. The adder 121 adds the power value PWCref and the power command value Pref′. The divider 122 divides the output from the adder 121 by the battery voltage VB to set a charging upper limit value IBCmax (however, a negative value). This charging upper limit value IBCmax is used as the upper limit value of the limiters 54 and 56 and the lower limit value of the limiter 72.

[0082] As described above, according to this embodiment, the power command corrector 64 corrects the power command value Pref using the actual power value P of the DC bus 2, and the charging rate control unit 33a calculates the charging rate target current value IBEref' using the corrected power command value Pref' and the battery voltage VB. This makes it possible to make the actual power supplied from the storage device 4 to the DC bus 2 approach the power command value Pref. This makes it possible to improve the accuracy with which the actual power of the DC bus 2 follows the power command value Pref.

[0083] Furthermore, since the upper limit values ​​of the limiters 44, 46, 54, and 56 and the upper and lower limit values ​​of the limiter 72 are adjusted based on the corrected power command value Pref', it is possible to provide a margin to the upper and lower limit ranges of the limiters 44, 46, 54, 56, and 72 by the amount of correction of the power command value Pref. This makes it possible to avoid the changes in the target charging current value IBDref and the target discharging current value IBCref that accompany the correction of the power command value Pref being limited by the limiters, and it is possible to improve control accuracy such as response tracking.

[0084] Although the present disclosure has been described above using embodiments, the technical scope of the present disclosure is not limited to the scope described in the above embodiments. Various modifications or improvements can be made to the above embodiments without departing from the gist of the present disclosure, and such modifications or improvements are also included in the technical scope of the present disclosure.

[0085] For example, in the above-described embodiment, the case where the charge / discharge control system 10 is applied to the mechanical parking device 1 has been described as an example, but the application of the charge / discharge control system 10 is not limited to this. In other words, the charge / discharge control system 10 can be widely applied to systems in which a chargeable / dischargeable power storage device is connected to a DC bus.

[0086] (Additional notes) The charge / discharge control device, the charge / discharge control system, and the charge / discharge control method described in the above-described embodiments can be understood, for example, as follows.

[0087] A charge / discharge control device (30) according to a first aspect of the present disclosure is a charge / discharge control device (30) that controls charging / discharging of an electricity storage device (4) by controlling a power converter (20) connected between the electricity storage device (4) and a DC bus (2), and includes a discharge-time voltage control unit (31) that outputs a discharge target current value (IBDref) for increasing a voltage value (VC) of the DC bus when the voltage value (VC) of the DC bus is lower than a predetermined discharge start voltage value (VCDref), and a charge target current control unit (32) that outputs a charge target current value (IBDref) for decreasing a voltage value (VC) of the DC bus when the voltage value (VC) of the DC bus is higher than a predetermined charge start voltage value (VCCref). a charging-time voltage control unit (32) that outputs a current value (IBCref) of the power storage device (4); a charging rate control unit (33) that outputs a charging rate target current value (IBEref) for keeping the charging rate of the power storage device (4) within a predetermined range; a current command value setting unit (34) that calculates a current command value (IBref) by using the discharge target current value (IBDref), the charge target current value (IBCref), and the charging rate target current value (IBEref); and a control signal generation unit (38) that generates control signals (Pgate, Ngate) for the power converter (20) based on the current value (IB) of the power storage device and the current command value (IBref).

[0088] According to the above aspect, the current command value is calculated using the discharge target current value, the charge target current value, and the charging rate target current value, so that switching of the control law is not necessary, and it is possible to eliminate response delays and the like caused by the switching law.

[0089] In a charge / discharge control device (30) according to a second aspect of the present disclosure, in the above-described first aspect, the discharge voltage control section (31) includes a proportional control section (42) to which a difference between a voltage value (VC) of the DC bus and the discharge start voltage value (VCDref) is input, an integral control section (42) to which the difference between the voltage value of the DC bus and the discharge start voltage value is input, and an adder (45) that calculates the discharge target current value (IBDref) by adding an output of the proportional control section and an output of the integral control section, and the adder (45) receives an output of the proportional control section (42) without passing through a limiter.

[0090] According to the above aspect, it is possible to prevent the output from the proportional control unit from being suppressed by the limiter, thereby improving the response performance to fluctuations in the bus voltage.

[0091] A charge / discharge control device (30) according to a third aspect of the present disclosure is the first or second aspect, wherein the charging voltage control section (32) includes a proportional control section (52) to which a difference between a voltage value (VC) of the DC bus and the charging start voltage value (VCCref) is input, an integral control section (53) to which the difference between the voltage value of the DC bus and the charging start voltage value is input, and an adder section (55) that calculates the charging target current value (IBCref) by adding an output of the proportional control section and an output of the integral control section, and the adder section (55) receives an output of the proportional control section (52) without passing through a limiter.

[0092] According to the above aspect, it is possible to prevent the output from the proportional control unit from being suppressed by the limiter, thereby improving the response performance to fluctuations in the bus voltage.

[0093] A charge / discharge control device (30) according to a fourth aspect of the present disclosure is any one of the first to third aspects, wherein the current command value setting unit (34) includes an adder (71) that adds the discharge target current value (IBDref), the charge target current value (IBCref), and the charging rate target current value (IBEref), and a limiter (72) that limits an output from the adder within a predetermined upper and lower limit range.

[0094] According to the above aspect, since the current command value is calculated using the discharge target current value, the charge target current value, and the charging rate target current value, it is not necessary to switch the control law, and it is possible to eliminate response delays caused by the switching law. Furthermore, since the current command value is set within a predetermined upper and lower limit range by the limiter, it is possible to suppress the charge / discharge current of the power storage device within an appropriate current range.

[0095] A charge / discharge control device (30) according to a fifth aspect of the present disclosure is, in any of the first to fourth aspects, provided with a power command correction unit (93) that corrects a power command value (Pref) using an actual power value (P) of the DC bus, and the charging rate control unit (33a) calculates the charging rate target current value (IBEref') using the corrected power command value (Pref') and a voltage value (VB) of the power storage device.

[0096] According to the above aspect, it is possible to make the actual power supplied from the power storage device to the DC bus closer to the power command value, thereby improving the accuracy with which the actual power on the DC bus follows the power command value.

[0097] A charge / discharge control system (10) according to a sixth aspect of the present disclosure includes a power converter (20) connected between an electricity storage device (4) and a DC bus (2), and a charge / discharge control device (30, 30a) according to any one of the first to fifth aspects.

[0098] A mechanical parking device (1) according to a seventh aspect of the present disclosure includes the charge / discharge control system according to the sixth aspect.

[0099] A charge / discharge control method according to an eighth aspect of the present disclosure is a charge / discharge control method for controlling charging / discharging of an electric power storage device (4) by controlling a power converter (20) connected between the electric power storage device (4) and a DC bus (2), the charge / discharge control method including: a process of outputting a discharge target current value (IBDref) for increasing a voltage value (VC) of the DC bus when the voltage value (VC) of the DC bus is lower than a predetermined discharge start voltage value (VCDref); and a process of outputting a discharge target current value (IBDref) for decreasing the voltage value (VC) of the DC bus when the voltage value (VC) of the DC bus is higher than a predetermined charge start voltage value (VCCref). a process of outputting a charging target current value (IBCref) for setting the charging rate of the power storage device (4) within a predetermined range; a process of calculating a current command value (IBref) using the discharging target current value (IBDref), the charging target current value (IBCref), and the charging rate target current value (IBEref); and a process of generating control signals (Pgate, Ngate) for the power converter (20) based on the current value (IB) of the power storage device and the current command value (IBref).

[0100] A program according to a ninth aspect of the present disclosure is a program for causing a computer to function as the charge / discharge control device (30, 30a) according to any one of the first to fifth aspects. [Explanation of symbols]

[0101] 1: Mechanical parking device 2 :DC bus 3: Load 4: Energy storage device 6: Power converter 7: Power converter 8: Transformer 10: Charge and discharge control system 20: Power converter 21: Reactor 22: Switching section 23: Capacitor 24: Switching element 25: Switching element 26: Voltage sensor 27: Current sensor 28: Voltage sensor 29: Current sensor 30: Charge / discharge control device 30a: Charge / discharge control device 31: Discharge voltage control section 32: Charging voltage control section 33: Charging rate control unit 33a: Charging rate control unit 34: Current command value setting unit 35: Current control section 36: Gate signal generation unit 38: Control signal generation unit 40:EMS 41: Subtraction section 42: Proportional control unit 43: Integral control section 44: Limiter 45: Addition section 46: Limiter 50: VPP gateway PC 51: Subtraction section 52: Proportional control unit 53: Integral control section 54: Limiter 55: Addition section 56: Limiter 61: Division part 62: Lamp control unit 63: Lamp control unit 64: Power command correction section 65: Division part 71: Addition section 72: Limiter 81: Subtraction section 82: Proportional control unit 83: Integral control section 84: Limiter 85: Addition section 86: Limiter 91: Actual power value calculation unit 92: Correction value calculation unit 93: Addition section 100: Power system 110: Upper limit setting section 111: Subtraction section 112: Proportional control unit 113: Integral control section 114: Limiter 115: Addition section 116: Limiter 120: Upper limit setting section 121: Addition section 122: Division part 131: Addition section 132 :Division part

Claims

1. A charge / discharge control device that controls charging / discharging of a power storage device by controlling a power converter connected between the power storage device and a DC bus, a discharge-time voltage control unit that outputs a discharge target current value for increasing the voltage value of the DC bus when the voltage value of the DC bus is lower than a predetermined discharge start voltage value; a charging voltage control unit that outputs a charging target current value for reducing the voltage value of the DC bus when the voltage value of the DC bus is higher than a predetermined charging start voltage value; a charging rate control unit that outputs a charging rate target current value for keeping the charging rate of the power storage device within a predetermined range; a current command value setting unit that calculates a current command value using the discharge target current value, the charge target current value, and the charging rate target current value; a control signal generation unit that generates a control signal for the power converter based on the current value of the power storage device and the current command value; A charge / discharge control device comprising:

2. The discharge voltage control unit is a proportional control unit to which a difference between the voltage value of the DC bus and the discharge start voltage value is input; an integral control unit to which a difference between the voltage value of the DC bus and the discharge start voltage value is input; an adder that calculates the discharge target current value by adding the output of the proportional control unit and the output of the integral control unit; Equipped with 2. The charge / discharge control device according to claim 1, wherein the output of the proportional control section is input to the adding section without passing through a limiter.

3. The charging voltage control unit is a proportional control unit to which a difference between the voltage value of the DC bus and the charging start voltage value is input; an integral control unit to which a difference between the voltage value of the DC bus and the charging start voltage value is input; an adder that calculates the charging target current value by adding the output of the proportional control unit and the output of the integral control unit; Equipped with 2. The charge / discharge control device according to claim 1, wherein the output of the proportional control section is input to the adding section without passing through a limiter.

4. The current command value setting unit an adder that adds together the target discharge current value, the target charge current value, and the target charging rate current value; a limiter that limits the output from the adding unit within a predetermined upper and lower limit range; The charge / discharge control device according to claim 1 , comprising:

5. a power command correction unit that corrects a power command value using an actual power value of the DC bus; The charge / discharge control device according to claim 1 , wherein the charging rate control unit calculates the charging rate target current value using the corrected power command value and a voltage value of the power storage device.

6. a power converter connected between the power storage device and the DC bus; A charge / discharge control device according to any one of claims 1 to 5; A charge / discharge control system comprising:

7. A mechanical parking device comprising the charge / discharge control system according to claim 6.

8. A charge / discharge control method for controlling charging / discharging of a power storage device by controlling a power converter connected between the power storage device and a DC bus, comprising: a process of outputting a discharge target current value for increasing the voltage value of the DC bus when the voltage value of the DC bus is lower than a predetermined discharge start voltage value; a process of outputting a target charging current value for reducing the voltage value of the DC bus when the voltage value of the DC bus is higher than a predetermined charging start voltage value; a process of outputting a target current value for a charging rate of the power storage device to keep the charging rate within a predetermined range; a process of calculating a current command value using the discharge target current value, the charge target current value, and the charging rate target current value; generating a control signal for the power converter based on the current value of the power storage device and the current command value; The computer executes the charge and discharge control method.

9. A program for causing a computer to function as the charge / discharge control device according to any one of claims 1 to 5.

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