JP7439799B2 - Charge/discharge device and battery connection device - Google Patents

Description

The present invention relates to a charging/discharging device and a battery connection device, and particularly to a technique for transmitting power between a power supply network and a battery.

BACKGROUND ART Electric vehicles such as hybrid vehicles and electric vehicles that run using power from secondary batteries are widely used. For electric vehicles, charging devices connected to the power supply network provided by electric power companies are installed at service stations, parking lots, and the like. The secondary battery of an electric vehicle is charged by a charging device.

Furthermore, in factories, offices, event venues, and the like, electric devices that use secondary batteries, such as forklifts, transport vehicles, and cleaning robots, are used. BACKGROUND ART In order to use a plurality of electric devices at various locations within the premises of factories, offices, etc., charging systems have been developed in which charging devices are connected to key points in a locally constructed power supply network.

The charging device includes a switching circuit that supplies power from the power supply network to an electric vehicle or an electric device (hereinafter collectively referred to as a battery-equipped device). The battery-equipped device also includes a switching circuit that supplies power acquired from the charging device to the secondary battery. Power is transmitted via a transformer between the switching circuit on the charging device side and the switching circuit on the battery-equipped device side.

The following Patent Documents 1 to 4 describe power conversion devices that couple two switching circuits using a transformer. In the power conversion devices described in Patent Documents 1 to 3, a transformer is configured by coupling a connector having a primary winding and a connector having a secondary winding. Patent Document 4 below describes a technique for performing contactless control communication using a coupling element between switching circuits that perform contactless power transmission.

Further, as a matter related to the present invention, Patent Document 5 describes a system in which contactless power supply is performed between a plurality of modules assembled in a vehicle. Patent Document 6 describes a power source in which a contactless power transmission circuit, a contactless power reception circuit, and a unit cell are housed in one case.

US Patent No. 5,341,083 US Patent Publication No. 2017/179765 JP2021-27281A Japanese Patent Application Publication No. 2019-187006 Japanese Patent Application Publication No. 2016-88169 Japanese Patent Application Publication No. 2018-191508

In recent years, research has been conducted on a technology called V2G (Vehicle to Grid). In V2G, power is supplied from a secondary battery mounted on an electric vehicle to a power supply grid, or power is supplied from a power supply grid to a secondary battery. Furthermore, in the above-mentioned charging system, control is considered to supply charging power from a secondary battery in one charging device to a secondary battery in another charging device via a locally constructed power supply network.

In this way, for battery-equipped devices that charge the secondary battery with power supplied from the power supply network and perform bidirectional power transmission that supplies power from the secondary battery to the power supply network, No specific control process has been established depending on the situation. The status of the power supply network includes, for example, the power supplied by a device operating as a power supply source among multiple battery-equipped devices connected to the power supply network, and the power obtained by a device operating as a load. There is a size relationship with electricity.

An object of the present invention is to perform bidirectional power transmission between a secondary battery and a power supply network depending on the status of the power supply network.

The present invention relates to a charging/discharging device that is connected to a power supply network and performs contactless power transmission with a battery unit including a battery, comprising a charging/discharging switching circuit for performing the contactless power transmission, and comprising: A switching signal for determining a transmission power target value for the battery based on a DC grid voltage given from a power supply network, switching the charging/discharging switching circuit according to the transmission power target value, and controlling switching of the battery unit. is generated according to the transmission power target value, and the switching signal is transmitted to the battery unit by non-contact communication.

Preferably, a charging/discharging characteristic setting value representing a change in the DC grid voltage with respect to a change in the current flowing through the charging/discharging device, and a no-load voltage representing a voltage at a connection end to the power supply network when in a no-load state. A set value is set, and the transmission power target value is determined from the measured value of the DC grid voltage, the charge/discharge characteristic set value, and the no-load voltage set value.

Preferably, a voltage measurement value between terminals of a power storage element included in the battery unit is acquired through the non-contact communication, and the switching signal is generated based on the voltage measurement value and the DC grid voltage measurement value. do.

Preferably, switching is not performed when the voltage measurements are not obtained by the contactless communication.

Preferably, the battery unit does not perform switching when the switching signal is not acquired through the contactless communication.

Preferably, two switching arms connected in parallel, each switching arm comprising two switching elements connected in series, and two switching arms in one of the two switching arms. The non-contact communication is performed between the battery unit and the winding connected between the series connection point of the element and the series connection point of the two switching elements on the other side, and each switching arm of each switching arm. a charge/discharge controller, wherein the DC grid voltage is applied between two parallel connection points of each switching arm.

Preferably, in the battery connecting device which configures the battery unit by connecting the batteries and performs the contactless power transmission with the charging/discharging device, the battery connecting device comprises two switching legs connected in parallel. , two switching legs each comprising two switching elements connected in series, a series connection point of two switching elements in one of the two switching legs, and a series connection point of two switching elements in the other of the two switching legs; a battery controller that performs the contactless communication between a second winding connected to a connection point and the charging/discharging device and switching each of the switching legs in accordance with the switching signal; and the battery is connected between a tap of the second winding and one of two parallel connection points of each switching arm.

The present invention also provides a battery connection device that performs contactless power transmission between a battery and a charging/discharging device connected to a power supply network, in which two switching legs are connected in parallel and connected in series. two switching legs each comprising two switching elements connected; a series connection point of two switching elements in one of the two switching legs; and a series connection point of two switching elements in the other of the two switching legs. performing contactless communication between the winding connected between the charging and discharging device and the charging and discharging device, and switching each of the switching legs in accordance with a switching signal acquired from the charging and discharging device by the contactless communication. and a battery controller, wherein the battery is connected between a tap of the winding and one of two parallel connection points of each of the switching arms.

According to the present invention, bidirectional power transmission can be performed between the secondary battery and the power supply network depending on the status of the power supply network.

1 is a diagram showing the configuration of a battery operation system according to an embodiment of the present invention. FIG. 2 is a diagram showing a specific configuration of a battery operation system. FIG. 3 is a diagram showing an example of a charge/discharge connector. It is a figure showing an example of a battery unit. FIG. 2 is a diagram showing the configuration of a charge/discharge control device included in a charge/discharge controller. 1 is a diagram illustrating an example of an electrical device connector; FIG. FIG. 2 is a diagram showing the configuration of a discharge control device included in a battery controller. It is a flowchart of charge/discharge processing. FIG. 3 is a diagram conceptually showing a charge/discharge map. FIG. 3 is a diagram conceptually showing a charge/discharge map.

Embodiments of the present invention will be described with reference to each figure. The same items shown in multiple drawings are designated by the same reference numerals to simplify the explanation. In this specification, directional terms such as "upper" and "lower" refer to directions in the drawings. Moreover, the term "battery" in this specification means a secondary battery.

FIG. 1 shows the configuration of a battery operation system 100 according to an embodiment of the present invention. The battery operation system 100 includes an AC power grid 10, an AC/DC converter 12, a DC power grid 14, a charging/discharging connector 16, a battery unit 18, an electric device 20, and a solar battery system 24.

The AC power network 10 may be a power supply network provided by a power supply company. The DC power network 14 may be a power supply network built locally in a factory, office, or the like. The AC/DC converter 12 performs AC/DC conversion, converts AC power supplied from the AC power grid 10 into DC power, and supplies the DC power to the DC power grid 14 . Further, the AC/DC converter 12 performs DC/AC conversion, converts the DC power supplied from the DC power grid 14 into AC power, and supplies the AC power to the AC power grid 10 . A plurality of charge/discharge connectors 16 for coupling battery units 18 are connected to the DC power network 14 .

The battery operation system 100 operates a battery unit 18 as a power source. That is, in the battery operation system 100, the battery 26 of the battery unit 18 is charged with power supplied from the DC power grid 14. When charging the battery 26, the battery unit 18 is coupled to the charge/discharge connector 16, and the battery unit 18 is electrically connected to the DC power grid 14. The battery unit 18 with the charged battery 26 is removed from the charging/discharging connector 16 and coupled to the electrical device 20, and power from the battery 26 is supplied to the electrical device 20. The battery unit 18 whose battery 26 is insufficiently charged is removed from the electrical device 20 and reconnected to the charging/discharging connector 16, and the battery 26 of the battery unit 18 is charged by the power supplied from the DC power grid 14.

Note that the battery unit 18 may supply power to another battery unit 18 coupled to another charge/discharge connector 16 to charge the battery 26 included in the other battery unit 18. The battery unit 18 may be fixed to a battery-equipped device such as a forklift, a transport vehicle, or an electric bicycle, or may be a device detachably attached thereto.

The battery unit 18 includes a battery 26 and a battery connector 28 to which the battery 26 is connected. The battery 26 may be detachably attached to the battery connector 28. The battery connector 28 is detachable from the charge/discharge connector 16. By coupling the charge/discharge connector 16 and the battery connector 28, power transmission is performed between the charge/discharge connector 16 and the battery connector 28.

Electrical device 20 may be a battery-powered device. The electrical device 20 includes an electrical device connector 30 and a device body portion 32. Electrical device connector 30 is removably attachable to battery connector 28 . That is, by coupling the electrical device connector 30 and the battery connector 28, contactless power transmission is performed between the battery connector 28 and the electrical device connector 30.

The solar cell system 24 includes a solar cell 34 and a DC/DC converter 36. The DC/DC converter 36 adjusts the voltage output by the solar cell 34 and outputs it to the DC power grid 14, and supplies DC power from the solar cell 34 to the DC power grid 14.

FIG. 2 shows a specific configuration of the battery operation system 100. The charge/discharge connector 16 includes a charge/discharge switching circuit 40, a first winding 42, and a charge/discharge controller 44. The charge/discharge switching circuit 40 is connected to a pair of DC power lines 47 in the DC power network 14 . The charge/discharge controller 44 is connected to a communication line 49. The battery unit 18 includes a battery connector 28 and a battery 26, and the battery connector 28 includes a battery switching circuit 46, a second winding 48, and a battery controller 50. The battery 26 is connected to the battery switching circuit 46 .

As shown in the upper part of FIG. 2, by coupling the battery connector 28 to the charge/discharge connector 16, the first winding 42 of the charge/discharge connector 16 and the second winding 48 of the battery connector 28 are connected. Join. Thereby, the first winding 42 and the second winding 48 constitute a transformer.

The charge/discharge controller 44 may acquire information used to control the charge/discharge connector 16 and the battery connector 28 from the host computer 45 via the communication line 49. The charge/discharge controller 44 and the battery controller 50 perform contactless communication. The charge/discharge controller 44 and the battery controller 50 transmit and receive control signals to and from each other. The control signal sent by the charge/discharge controller 44 to the battery controller 50 includes information indicating the state of the charge/discharge switching circuit 40 (voltage measurement values, current measurement values, etc. of each part) in addition to commands to the battery controller 50. Good too. The control signal sent from the battery controller 50 to the charge/discharge controller 44 includes information indicating the state of the battery switching circuit 46 (voltage measurement values, current measurement values, etc. of each part) in addition to commands to the charge/discharge controller 44. Good too.

The charge/discharge controller 44 controls the switching of the charge/discharge switching circuit 40 , and the battery controller 50 controls the switching of the battery switching circuit 46 . As a result, power is supplied from the DC power grid 14 to the battery 26, or power is supplied from the battery 26 to the DC power grid 14.

The electrical device 20 shown on the lower left side of FIG. 2 includes a rectifier circuit 52, a device main body 32, a third winding 56, and an electrical device controller 54. The rectifier circuit 52 in this embodiment is configured by a diode that does not require switching control. A battery is mounted on the device main body 32. As shown in the middle part of FIG. 2, the battery unit 18 whose battery 26 has been fully charged is removed from the charge/discharge connector 16. As shown in the bottom row, coupling the battery connector 28 of the battery unit 18 to the electrical device connector 30 of the electrical device 20 causes a second winding 48 included in the battery connector 28 and a second winding 48 included in the electrical device connector 30 to be connected to the electrical device connector 30 of the electrical device 20. Three windings 56 are coupled. Thereby, the second winding 48 and the third winding 56 constitute a transformer.

Battery controller 50 and electrical device controller 54 communicate without contact. Battery controller 50 and electrical device controller 54 send and receive control signals to and from each other. The control signal sent from the battery controller 50 to the electrical device controller 54 includes information indicating the state of the battery switching circuit 46 (voltage measurement values, current measurement values, etc. of each part) in addition to commands to the electrical device controller 54. Good too. The control signal sent by the electrical device controller 54 to the battery controller 50 may include information indicating the state of the electrical device 20 (voltage measurement values, current measurement values, etc. of each part) in addition to instructions for the battery controller 50. .

The battery controller 50 performs switching control of the battery switching circuit 46. AC power is supplied from the battery 26 to the rectifier circuit 52 via the battery switching circuit 46, the second winding 48, and the third winding 56, and the DC power obtained by the rectifier circuit 52 is supplied to the device main body 32. be done. As a result, the battery included in the device main body 32 may be charged. Alternatively, the device main body 32 may be operated by power supplied from the rectifier circuit 52.

FIG. 3 shows an example of the charge/discharge connector 16. The charging/discharging connector 16 is a charging/discharging device that is connected to the DC power network 14 and performs contactless power transmission with the battery unit 18. The charge/discharge switching circuit 40 included in the charge/discharge connector 16 includes an input/output capacitor CA, switching arms U, V, a positive terminal 60p, and a negative terminal 60n. Each of switching arms U and V includes an upper switching element S1 and a lower switching element S2 connected in series. For each switching element, an IGBT (Insulated Gate Bipolar Transistor), a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), or the like may be used. When an IGBT is used as a switching element, two switching elements connected in series means that one emitter electrode is connected to the other collector electrode. When a MOSFET is used as a switching element, two switching elements connected in series means that the source electrode of one is connected to the drain electrode of the other.

When an IGBT is used as a switching element, the switching element includes a diode having an anode electrode connected to an emitter electrode of the IGBT and a cathode electrode connected to a collector electrode. When a MOSFET is used as a switching element, the switching element includes a diode whose anode electrode is connected to the source electrode of the MOSFET and whose cathode electrode is connected to the drain electrode.

Switching arms U and V are connected in parallel. That is, the upper ends of the upper switching elements S1 of each switching arm are connected in common, and the lower ends of the lower switching elements S2 of each switching arm are connected in common. Input/output capacitor CA is connected in parallel to switching arms U and V. That is, the input/output capacitor CA is connected between the upper parallel connection point and the lower parallel connection point of switching arms U and V. The upper ends of the input/output capacitor CA and switching arms U and V are connected to a positive terminal 60p, and the lower ends of the input/output capacitor CA and switching arms U and V are connected to a negative terminal 60n. The positive terminal 60p and the negative terminal 60n are connected to a pair of DC power lines 47 in the DC power network 14.

The first winding 42 is connected between the series connection point of the upper switching element S1 and the lower switching element S2 in the switching arm U and the series connection point of the upper switching element S1 and the lower switching element S2 in the switching arm V. ing.

The charge/discharge controller 44 is connected to a communication line 49. The charge/discharge controller 44 may communicate with a host computer 45 connected to a communication line 49. The charge/discharge controller 44 includes a coupling element 62 . The coupling element 62 is coupled to a coupling element included in the battery controller 50 of the battery unit 18 in a non-contact manner. The charge/discharge controller 44 performs non-contact communication with the battery controller 50 via its own coupling element 62 and the coupling element of the battery controller 50, and mutually transmits and receives control signals. The coupling element 62 may be a conductive element that couples with the coupling element included in the battery controller 50 in a near field, or may be a conductive element (antenna element) that couples in a far field.

According to the switching control by the charge/discharge controller 44, each switching arm operates as follows. The upper switching element S1 and lower switching element S2 of each switching arm are alternately turned on and off. That is, while the upper switching element S1 is switched from off to on, the lower switching element S2 is switched from on to off, and while the upper switching element S1 is switched from on to off, the lower switching element S2 is switched from off to on. The switching phase in which the switching arm U is turned on and off and the switching phase in which the switching arm V is turned on and off may be different by 180°. By switching the switching arms U and V, the voltage between the positive terminal 60p and the negative terminal 60n is switched and applied to the first winding 42.

The charge/discharge switching circuit 40, the charge/discharge controller 44, and the first winding 42 may be housed in a housing for coupling the battery unit 18 to the charge/discharge connector 16. In this case, a pair of conducting wires drawn out from the positive terminal 60p and a negative terminal 60n to the outside of the casing may be connected to the pair of DC power lines 47.

FIG. 4 shows an example of the battery unit 18. The battery unit 18 includes a battery 26 and a battery connector 28 to which the battery 26 is connected. The battery connector 28 is a battery connection device that performs contactless power transmission with the charge/discharge connector 16 (charge/discharge device). The battery switching circuit 46 included in the battery connector 28 includes a first capacitor C1, a second capacitor C2, switching legs X and Y, a positive terminal 66p, and a negative terminal 66n. Here, the term "switching leg" is used to distinguish it from the switching arms U and V used in the charge/discharge connector 16. Each of the switching legs X and Y includes an upper switching element S1 and a lower switching element S2 connected in series. IGBT, MOSFET, etc. may be used for each switching element.

Switching legs X and Y are connected in parallel. A first capacitor C1 is connected in parallel to switching legs X and Y. A second winding 48 is connected between the series connection point of the upper switching element S1 and the lower switching element S2 in the switching leg X and the series connection point of the upper switching element S1 and the lower switching element S2 in the switching leg Y. ing.

A tap is provided at a midpoint of the conducting wire forming the second winding 48 . The tap may be a center tap provided at the midpoint of the conductor forming the second winding 48 . A second capacitor C2 is connected between the lower end of the parallel connection point of the switching legs X, Y and the first capacitor C1 and the tap of the second winding 48. Further, a positive terminal 66p is connected to the tap of the second winding 48 via a battery current sensor Asp, and a negative terminal 66n is connected to the lower end of the parallel connection point of the switching legs X, Y and the first capacitor C1. ing. The positive electrode of the battery 26 is connected to the positive terminal 66p, and the negative electrode of the battery 26 is connected to the negative terminal 66n.

Battery controller 50 includes a coupling element 64 . The coupling element 64 is coupled in a non-contact manner to the coupling element 62 included in the charge/discharge controller 44 or the coupling element included in the electrical device controller 54. The charge/discharge controller 44 performs contactless communication between its own coupling element 64 and the charge/discharge controller 44 or the electric device controller 54 via the coupling element 64 of the charge/discharge controller 44 or the electric device controller 54, and communicates with each other. Send and receive control signals. The coupling element 64 may be a conductive element that couples in the near field with the coupling element 62 included in the charge/discharge controller 44 or the coupling element included in the electrical device controller 54, or may be a conductive element that couples in a far field. . The battery controller 50 further includes an antenna 65 and performs wireless communication with the host computer 45 via the antenna 65.

Under the switching control of the battery controller 50, each switching leg operates as follows. The upper switching element S1 and lower switching element S2 of each switching leg are alternately turned on and off. The switching phase in which switching leg X is turned on and off and the switching phase in which switching leg Y is turned on and off may be different by 180°.

A voltage obtained by boosting the voltage of the battery 26 is applied to the first capacitor C1. The boosted voltage is determined according to the duty ratio of the upper switching element S1 of the switching legs X and Y. Here, the duty ratio is the ratio of the time during which the upper switching element S1 is turned on to the switching period. Further, by switching the switching legs X and Y, a voltage obtained by switching the voltage between the terminals of the first capacitor C1 is applied to the second winding 48.

Battery switching circuit 46, battery controller 50, and second winding 48 may be housed in a housing for coupling battery unit 18 to charge/discharge connector 16 or electrical device connector 30. In this case, a pair of conductive wires drawn out from the positive terminals 66p and 66n to the outside of the casing may be connected to the positive and negative electrodes of the battery 26. Further, the battery 26 may be housed in the housing in addition to the battery switching circuit 46, the battery controller 50, and the second winding 48.

An example of the operation when the first winding 42 of the charge/discharge connector 16 and the second winding 48 of the battery connector 28 are coupled will be described. Each switching arm and each switching leg switch at the same frequency. The upper switching elements S1 of switching arms U and V and the upper switching elements S1 of switching legs X and Y operate at the same duty ratio α, and the duty ratio α is adjusted. Further, the phase difference φ between the switching of the switching leg X with respect to the switching of the switching arm U, and the phase difference φ between the switching of the switching leg Y with respect to the switching of the switching arm V are adjusted.

The electric power P transmitted from the charge/discharge connector 16 to the battery unit 18 is determined by the duty ratio α and the phase difference φ, and is adjusted by changing the duty ratio α and the phase difference φ. Note that when the power P has a negative value, power is transmitted from the battery unit 18 to the charge/discharge connector 16. Depending on the polarity of the phase difference φ, it is determined whether power is transmitted from the charge/discharge connector 16 to the battery unit 18 or from the battery unit 18 to the charge/discharge connector 16.

FIG. 5 shows the configuration of the charge/discharge control device 102 configured in the charge/discharge controller 44 when the first winding 42 of the charge/discharge connector 16 and the second winding 48 of the battery unit 18 are coupled. has been done. In the process executed by the charge/discharge control device 102, the DC grid voltage Vgg, the battery unit voltage Vbb, the transmission power target value Pcom1, and the transmission power Pout1 are used. The DC grid voltage Vgg is the voltage between the positive terminal 60p and the negative terminal 60n of the charge/discharge connector 16. The battery unit voltage Vbb is the voltage between the terminals of the first capacitor C1 included in the battery unit 18. The transmission power target value Pcom1 is a target value for the power transmitted from the charging/discharging connector 16 to the battery unit 18, and may be obtained in a charging/discharging process described later. Transmission power Pout1 is power transmitted from the charging/discharging connector 16 to the battery unit 18.

The charge/discharge connector 16 (FIG. 3) includes a DC grid voltage sensor Sg that measures the DC grid voltage Vgg. The charge/discharge connector 16 also includes a DC grid current sensor Asg that measures the DC grid current Igg flowing through the positive terminal 60p. The DC grid voltage sensor Sg and the DC grid current sensor Asg output measured values to the charge/discharge controller 44.

The battery unit 18 (FIG. 4) includes a battery unit voltage sensor Sb that measures the voltage across the terminals of the first capacitor C1, that is, the battery unit voltage Vbb. Battery unit voltage sensor Sb outputs a measured value to battery controller 50. The battery unit 18 also includes a battery voltage sensor Sp that measures the battery voltage Vb output from the battery 26 and a battery current sensor Asp that measures the battery current Ib flowing out from the battery 26. Battery voltage sensor Sp and battery current sensor Asp output measured values to battery controller 50. Battery controller 50 transmits each measured value of battery unit voltage Vbb, battery voltage Vb, and battery current Ib to charge/discharge controller 44.

The charge/discharge controller 44 determines the transmission power Pout1 based on the measured values of the DC grid voltage Vgg and the DC grid voltage Vgg. Further, the charge/discharge controller 44 may obtain the transmission power Pout1 based on the measured values of the battery voltage Vb and the battery current Ib.

The charge/discharge control device 102 includes a subtracter 81, an integrator 82, a subtracter 83, an adder 84, an integrator 85, a limiter 86, and a switching signal generator 87. These components may be virtually configured in the charge/discharge controller 44 by the charge/discharge controller 44 executing a program. Subtractor 81 subtracts battery unit voltage Vbb from DC grid voltage Vgg to obtain a first control value e1, and outputs it to integrator 82 and adder 84. The integrator 82 integrates the first control value e1 and multiplies it by a predetermined coefficient to obtain the duty ratio α. The subtracter 83 subtracts the transmission power Pout1 from the transmission power target value Pcom1 to obtain a second control value e2, and outputs it to the adder 84. The adder 84 adds the first control value e1 and the second control value e2 to obtain a third control value e3, and outputs the third control value e3 to the integrator 85. The integrator 85 integrates the third control value e3 and multiplies it by a predetermined coefficient to obtain the phase difference φ0. When the phase difference φ0 is greater than or equal to the negative limit value φm and less than or equal to the positive limit value φp, the limiter 86 outputs a phase difference φ having the same value as the phase difference φ0 to the switching signal generator 87. When the phase difference φ0 exceeds the positive limit value φp, the limiter 86 replaces the value of the phase difference φ0 with the limit value φp and outputs it to the switching signal generator 87 as the phase difference φ. When the phase difference φ0 is less than the negative limit value φm, the limiter 86 replaces the value of the phase difference φ0 with the negative limit value φm and outputs it to the switching signal generator 87 as the phase difference φ. In this way, the limiter 86 outputs to the switching signal generator 87 the phase difference φ whose value is limited to a range that is greater than or equal to the negative limit value φm and less than or equal to the positive limit value φp.

Switching signal generator 87 generates switching signals for upper switching element S1 and lower switching element S2 in each of switching arms U and V and each of switching legs X and Y, based on duty ratio α and phase difference φ. . The switching signal may be, for example, a signal whose value is high to turn on the switching element and whose value is low to turn off the switching element.

Charge/discharge controller 44 performs switching control of switching arms U and V based on each switching control signal generated for upper switching element S1 and lower switching element S2 of switching arms U and V, respectively. Charge/discharge controller 44 transmits each switching control signal generated for upper switching element S1 and lower switching element S2 of switching legs X and Y, respectively, to battery controller 50. The battery controller 50 controls switching of the switching legs X and Y based on each switching control signal transmitted from the charge/discharge controller 44.

Here, an embodiment has been shown in which a measured value of battery unit voltage Vbb is used to generate the switching signal. The charge/discharge control device 102 may use the measured value of the battery voltage Vb instead of the measured value of the battery unit voltage Vbb. In this case, the charge/discharge control device 102 calculates the battery unit voltage Vbb based on the measured value of the battery voltage Vb, and inputs the calculated battery unit voltage Vbb to the subtracter 81.

In this way, the charge/discharge control device 102 determines the duty ratio α based on the integral value of the difference between the transmission power target value Pcom1 and the transmission power Pout1. The charge/discharge control device 102 further determines the phase difference φ based on the difference between the transmission power target value Pcom1 and the transmission power Pout1 and the difference between the voltage measurement value in the battery unit 18 and the measurement value of the DC grid voltage Vgg. . The voltage measurement value in the battery unit 18 is a measurement value of the voltage between the terminals of the power storage element included in the battery unit 18. That is, the voltage measurement value in the battery unit 18 is the measurement value of the battery unit voltage Vbb, which is the voltage between the terminals of the first capacitor C1 (power storage element), or the battery voltage Vb, which is the voltage between the terminals of the battery 26 (power storage element). It is a measured value.

Through the configuration and processing of the charge/discharge control device 102, the power transmitted from the charge/discharge connector 16 to the battery unit 18 approaches or matches the transmission power target value Pcom1. If the phase difference φ falls outside the numerical range determined by the characteristics of the circuit, it becomes difficult to adjust the transmission power according to the phase difference φ. According to this embodiment, the limiter 86 limits the range in which the value of the phase difference φ can take, thereby avoiding such control breakdown.

FIG. 6 shows an example of an electrical device connector 30 as an electrical device connector. Electrical device connector 30 includes a rectifier circuit 52, a third winding 56, and an output capacitor CB. The rectifier circuit 52 includes diode arms Z and W forming a diode bridge. Each diode arm includes an upper diode D1 and a lower diode D2, and a cathode terminal of the lower diode D2 is connected to an anode terminal of the upper diode D1. Diode arms Z and W are connected in parallel. That is, the cathode terminals of the upper diodes D1 included in each diode arm are connected in common, and the anode terminals of the lower diodes D2 included in each diode arm are connected in common.

A third winding 56 is connected between the connection point between the upper diode D1 and the lower diode D2 in the diode arm Z and the connection point between the upper diode D1 and the lower diode D2 in the diode arm W. An output capacitor CB is connected in parallel to the diode arms Z and W. A positive output terminal 70p is connected to the upper parallel connection point of the diode arms Z, W and the output capacitor CB, and a negative output terminal 70n is connected to the lower parallel connection point. The device main body 32 is connected to the positive output terminal 70p and the negative output terminal 70n.

The rectifier circuit 52, electrical device controller 54, and third winding 56 may be housed in a housing for coupling the battery unit 18 to the electrical device connector 30. In this case, a pair of conductive wires drawn out from the positive output terminal 70p and the negative output terminal 70n to the outside of the casing may be connected to the device main body 32. Further, in addition to the rectifier circuit 52, the electric device controller 54, and the third winding 56, the device main body portion 32 may be housed in the housing.

An example of the operation when the second winding 48 of the battery connector 28 and the third winding 56 of the electrical device connector 30 are coupled will be described. By switching the switching legs X and Y at the same frequency with a certain phase difference, an alternating current voltage is applied to the second winding 48, which causes an alternating voltage to appear at the third winding 56. The AC voltage appearing at the third winding 56 is rectified by the rectifier circuit 52, and a DC voltage is applied to the output capacitor CB. As a result, DC power is output from the positive output terminal 70p and the negative output terminal 70n to the device main body 32.

A boosted voltage obtained by boosting the output voltage of the battery 26 by the inductance of the second winding 48 in the battery connector 28 can be output from the positive output terminal 70p and the negative output terminal 70n. This boosted voltage can be adjusted by changing the duty ratio β of the upper switching element S1 in each of the switching legs X and Y. Furthermore, by adjusting the boosted voltage, the power output from the positive output terminal 70p and the negative output terminal 70n to the device main body 32 can be adjusted.

FIG. 7 shows the configuration of the discharge control device 104 configured in the battery controller 50 when the second winding 48 of the battery unit 18 and the third winding 56 of the electrical device connector 30 are coupled. ing. In the process executed by the discharge control device 104, the transmission power target value Pcom2 and the transmission power Pout2 are used. The transmission power target value Pcom2 is a target value for the power transmitted from the battery unit 18 to the electrical device 20, and may be transmitted from the electrical device controller 54 to the battery controller 50, or may be set by the battery controller 50. . Transmitted power Pout2 is a measured value of power transmitted from battery unit 18 to electrical device 20.

The electrical device connector 30 (FIG. 6) includes an output voltage sensor Sq that measures an output voltage Vq between a positive output terminal 70p and a negative output terminal 70n. Further, the electrical device connector 30 includes an output current sensor Asq that measures an output current Iq flowing out from the positive output terminal 70p to the device main body portion 32. Output voltage sensor Sq and output current sensor Asq output measured values to electrical device controller 54. Electrical device controller 54 transmits each measurement value by output voltage sensor Sq and output current sensor Asq to battery controller 50.

Battery controller 50 determines transmission power Pout2 transmitted from battery unit 18 to electrical device 20 based on each measured value of output voltage Vq and output current Iq. Furthermore, the battery controller 50 may determine the transmission power Pout2 transmitted from the battery unit 18 to the electrical device 20 based on the battery voltage Vb and battery current Ib measured by the battery voltage sensor Sp and the battery current sensor Asp. .

The discharge control device 104 includes a subtracter 90, an integrator 91, a limiter 92, and a switching signal generator 93. These components may be virtually configured in the battery controller 50 by the battery controller 50 executing a program. The subtracter 90 subtracts the transmission power Pout2 from the transmission power target value Pcom2 to obtain a fourth control value e4, and outputs the fourth control value e4 to the integrator 91. The integrator 91 integrates the fourth control value e4 and multiplies it by a predetermined coefficient to obtain the duty ratio β0. The limiter 92 outputs a duty ratio β having the same value as the duty ratio β0 to the switching signal generator 93 when the duty ratio β0 is greater than or equal to the lower limit value βL and less than or equal to the upper limit value βU. When the duty ratio β0 exceeds the upper limit value βU, the limiter 92 replaces the value of the duty ratio β0 with the upper limit value βU and outputs it to the switching signal generator 93 as the duty ratio β. When the duty ratio β0 is less than the lower limit value βL, the limiter 92 replaces the value of the duty ratio β0 with the lower limit value βL and outputs it to the switching signal generator 93 as the duty ratio β. In this way, the limiter 92 outputs to the switching signal generator 93 the duty ratio β whose value is limited to a range that is greater than or equal to the lower limit value βL and less than or equal to the upper limit value βU.

Switching signal generator 93 generates switching signals for upper switching element S1 and lower switching element S2 in switching legs X and Y, respectively, based on duty ratio β. The switching signal may be, for example, a signal whose value is high to turn on the switching element and whose value is low to turn off the switching element. The battery controller 50 performs switching control of the switching legs X and Y based on each switching control signal generated for the upper switching element S1 and the lower switching element S2 of the switching legs X and Y, respectively.

Through the configuration and processing of the discharge control device 104, the power transmitted from the battery unit 18 to the electric device 20 approaches or matches the transmission power target value Pcom2. If the duty ratio β is outside the numerical range determined by the characteristics of the circuit, it becomes difficult to adjust the transmission power according to the duty ratio β. According to the present embodiment, the limiter 92 limits the range in which the duty ratio β can take, thereby avoiding such control breakdown.

FIG. 8 shows a flowchart of the charging/discharging process. The charging/discharging process is performed by the host computer 45, the charging/discharging controller 44, and the battery controller 50 when the battery unit 18 is coupled to the charging/discharging connector 16. Steps S101 and S102 are processes executed by the host computer 45. Steps S201 to S208 are processes executed by the charge/discharge controller 44. Steps S301 to S306 are processes executed by the battery controller 50.

The battery controller 50 transmits battery information regarding the battery 26 to the host computer 45 (S301). The battery information includes the output voltage of the battery 26 under no load, SOC (State Of Charge), SOH (State Of Health), full charge capacity, withstand voltage, allowable current, type (lithium ion, nickel cadmium, etc.), etc. May contain information. The host computer 45 generates charge/discharge information based on the battery information (S101), and transmits it to the charge/discharge controller 44 (S102). The charging/discharging information may include, for example, information such as the output voltage of the battery 26 under no load, the current SOC, the target value of the SOC, and how quickly the battery 26 is charged or discharged.

The charge/discharge controller 44 sets a charge/discharge map, which will be described later, based on the charge/discharge information (S201). The charge/discharge map is information for determining the transmission power target value Pcom1.

The battery controller 50 acquires each measurement value of the battery unit voltage sensor Sb, battery voltage sensor Sp, and battery current sensor Asp, and transmits it to the charge/discharge controller 44 (S302). The charge/discharge controller 44 determines whether all measured values have been received (S202). When the charge/discharge controller 44 determines that any measurement value has not been received, it stops switching control of the switching arms U and V (S208). Here, stopping the switching control of the switching arms U and V includes stopping the switching of the switching arms U and V that have been switched so far, as well as stopping the switching of the switching arms U and V that have not been switched so far. This includes maintaining arms U and V in a non-switching state.

Note that the process of step S202 may be a process of determining whether the charge/discharge controller 44 has received a signal to be transmitted from the battery controller 50 to the charge/discharge controller 44.

On the other hand, when the charge/discharge controller 44 determines that all measured values have been received, it determines whether the local operation is normal (S203). Here, normal local operation means that the circuit constituting the charge/discharge connector 16 satisfies predetermined operating conditions. The operating conditions include, for example, a condition that the range of the measured values by the DC grid voltage sensor Sg and the DC grid current sensor Asg is within a predetermined range. When the charge/discharge controller 44 determines that the local operation is not normal, it stops switching control of the switching arms U and V (S208). When the charge/discharge controller 44 determines that the local operation is normal, the charge/discharge controller 44 determines the transmission power target value Pcom1 by processing using a charge/discharge map, as described below.

FIG. 9 conceptually shows a charge/discharge map. The horizontal axis shows the DC grid current Igg, and the vertical axis shows the DC grid voltage Vgg. In the charge/discharge map, in areas where the DC grid current Igg is positive, the battery 26 is discharged, power is transmitted from the battery unit 18 to the charge/discharge connector 16, and power is output from the charge/discharge connector 16 to the DC power grid 14. correspond to the state. The region where the DC grid current Igg is negative corresponds to a state where power is supplied from the DC power grid 14 to the charge/discharge connector 16, power is transmitted from the charge/discharge connector 16 to the battery unit 18, and the battery 26 is charged. In the charge/discharge map, an upper limit value Imax and a lower limit value Imin are defined for the DC grid current Igg.

The charge/discharge controller 44 sets the charge/discharge line L on the charge/discharge map based on the charge/discharge information transmitted from the host computer 45 . The charging/discharging line L is determined based on the DC grid voltage V0 when the battery 26 is in an unloaded state and the rate of change (charging/discharging resistance) of the DC grid voltage Vgg with respect to the DC grid current Igg. That is, the charge/discharge controller 44 obtains a linear function straight line with the no-load DC grid voltage V0 as the vertical axis intercept and the slope as the charge/discharge resistance as the charge/discharge line L. Here, the no-load DC grid voltage V0 is obtained by converting the no-load output voltage of the battery 26 into the voltage between the positive terminal 60p and the negative terminal 60n, that is, the DC grid voltage Vgg. Further, the slope of the charging/discharging line can be obtained by converting the value of the charging/discharging resistance into the value at the positive terminal 60p and the negative terminal 60n.

The charging/discharging controller 44 refers to the charging/discharging line L set in the charging/discharging map, and calculates the DC grid current Igg corresponding to the measured value (value on the vertical axis) of the DC grid voltage Vgg obtained by the DC grid voltage sensor Sg. (value on the horizontal axis) is obtained as the DC grid current target value. The charge/discharge controller 44 determines the transmission power target value Pcom1 based on the measured value of the DC grid voltage Vgg and the DC grid current target value.

When the DC grid voltage V0 during no-load is larger than the measured value of the DC grid voltage Vgg, the DC grid current target value becomes a positive value, and the target power discharged from the charging/discharging connector 16 to the DC power grid 14 A transmission power target value Pcom1 is determined as the value. On the other hand, when the DC grid voltage V0 during no-load is smaller than the measured value of the DC grid voltage Vgg, the DC grid current target value becomes a negative value, and the electric power charged from the DC power grid 14 to the battery 26 A transmission power target value Pcom1 is determined as the target value.

In FIG. 10, three charge/discharge lines L0, L1, and L2 are shown as an example. The charge/discharge lines L0, L1, and L2 are straight lines whose vertical axis intercepts are V00, V01, and V02, respectively, and whose slopes are R0, R1, and R2, respectively. The following relationships hold: V01<V00<V02 and |R0|<|R2|<|R1|.

The magnitude of the slope R1 of the charge/discharge line L1 is larger than the magnitude of the slope R2 of the charge/discharge line L2. Therefore, it takes longer for the transmission power to reach the transmission power target value Pcom1 when the transmission power target value Pcom1 is determined according to the charge/discharge line L1 than when the transmission power target value Pcom1 is determined according to the charge/discharge line L2. Become. The magnitude of the slope R2 of the charge/discharge line L2 is larger than the magnitude of the slope R0 of the charge/discharge line L0. Therefore, it takes longer for the transmission power to reach the transmission power target value Pcom1 when the transmission power target value Pcom1 is determined according to the charge/discharge line L2 than when the transmission power target value Pcom1 is determined according to the charge/discharge line L0. Become.

In this manner, in the charging/discharging process, a charging/discharging resistance (charging/discharging characteristic setting value) representing a change in the DC grid voltage Vgg with respect to a change in the DC grid current Igg flowing through the charging/discharging connector 16 is set. In addition, the voltage at the connection end to the DC power grid 14 in a no-load state, that is, the value of the vertical axis intercept representing the voltage between the positive terminal 60p and the negative terminal 60n (no-load voltage setting value) is set. be done. Then, the transmission power target value is determined from the measured value of the DC grid voltage Vgg, the charging/discharging resistance as the charging/discharging characteristic setting value, and the value of the vertical axis intercept as the no-load voltage setting value. Specifically, a linear function that connects the DC grid current Igg and the DC grid voltage Vgg is set, and the DC grid current Igg (value on the horizontal axis) corresponding to the measured value (value on the vertical axis) of the DC grid voltage Vgg is set. , obtained as the DC grid current target value. Furthermore, a transmission power target value Pcom1 is determined based on the measured value of the DC grid voltage Vgg and the DC grid current target value.

Returning to FIG. 8, the processing executed by the charge/discharge controller 44 and the battery controller 50 will be described. The charge/discharge controller 44 constitutes the charge/discharge control device 102 shown in FIG. 5, and generates switching signals for switching arms U and V and switching legs X and Y (S205). The charge/discharge controller 44 transmits switching signals for the switching legs X and Y to the battery controller 50 (S206), and performs switching control for the switching arms U and V (S207).

The battery controller 50 determines whether a switching signal has been received (S303). When the battery controller 50 determines that the switching signal has not been received, it stops switching the switching legs X and Y (S306). Here, stopping the switching control of the switching legs X and Y includes stopping the switching of the switching legs This includes maintaining legs X and Y in a non-switching state.

Further, when the battery controller 50 determines that a switching signal has been received, the battery controller 50 determines whether the local operation is normal. Normal local operation means that the circuits forming the battery unit 18 satisfy predetermined operating conditions. The operating conditions include, for example, a condition that the ranges of measured values by the battery unit voltage sensor Sb, battery voltage sensor Sp, and battery current sensor Asp are within a predetermined range. When the battery controller 50 determines that the local operation is not normal, it stops switching the switching legs X and Y (S306). When the battery controller 50 determines that the local operation is normal, it performs switching control on the switching legs X and Y (S306).

The contactless communication in steps S301, S102, and S302 may be communication using packets. On the other hand, the non-contact communication in step S206 may be communication using a signal such as a pulse signal whose rising or falling edge directly indicates the switching timing. Since the non-contact communication in step S206 does not require complicated modulation processing or the like, the switching timing is quickly transmitted from the charge/discharge controller 44 to the battery controller 50.

In the charging/discharging process according to the present embodiment, the transmission power target value Pcom1 is determined based on the charging/discharging map. This transmission power target value Pcom1 is determined from the relationship between the output voltage of the battery 26 at no load and the measured value of the DC grid voltage Vgg. Therefore, charging and discharging control of the battery 26 is executed adaptively and autonomously with respect to the DC grid voltage Vgg, which is the voltage of the DC power grid 14.

From the viewpoint that each of the plurality of battery units 18 is connected to the DC power grid 14 via the charge/discharge connector 16, the following effects can be obtained. That is, when there are a plurality of battery units 18 with different vertical axis intercepts V0, the battery unit 18 with a larger vertical axis intercept V0 is supplied with greater power than the battery unit 18 with a smaller vertical axis intercept V0. Further, when there are a plurality of battery units 18 with different charging/discharging resistances R, the battery unit 18 with the smaller charging/discharging resistance R is supplied with greater power than the battery unit 18 with the larger charging/discharging resistance R. As a result, the power supply and demand balance in the DC power network 14 is adjusted in an autonomous and decentralized manner in each charging/discharging connector 16 and each battery unit 18.

Further, in the charging/discharging process according to the present embodiment, when the charging/discharging controller 44 does not receive the measured values of the battery unit voltage sensor Sb, battery voltage sensor Sp, and battery current sensor Asp, the charging/discharging controller 44: Stop switching of switching arms U and V. Further, when the battery controller 50 does not receive the switching signal, the battery controller 50 stops switching the switching legs X and Y. This prevents the switching arms U and V from being switched when the battery unit 18 is not coupled to the charge/discharge connector 16. Similarly, switching of switching legs X and Y is avoided when battery unit 18 is not coupled to charge/discharge connector 16 .

If switching arms U and V or switching legs X and Y are switched in a state where charge/discharge connector 16 and battery unit 18 are not connected, power may be wasted in each switching element. Further, depending on the situation in which the first winding 42 is placed, such as when the first winding 42 is in contact with a foreign object, an excessive current may flow through the switching elements that constitute the switching arms U and V. Similarly, depending on the situation in which the second winding 48 is placed, such as when the second winding 48 is in contact with a foreign object, an excessive current may flow through the switching elements that constitute the switching legs X and Y. . According to the charging/discharging element according to the present embodiment, the electrical load applied to each switching element is reduced in a state where the charging/discharging connector 16 and the battery unit 18 are not connected. Further, in a state where the charge/discharge connector 16 and the battery unit 18 are not connected, the power consumed by each switching element is reduced.

10 AC power network, 12 AC/DC converter, 14 DC power network, 16 charging/discharging connector, 18 battery unit, 20 electrical device, 24 solar cell system, 26 battery, 28 battery connector, 30 electrical device connector, 32 device main body, 34 Solar cell, 36 DC/DC converter, 40 Charge/discharge switching circuit, 42 First winding, 44 Charge/discharge controller, 45 Host computer, 46 Battery switching circuit, 47 DC power line, 48 Second winding, 49 Communication line, 50 Battery controller, 52 Rectifier circuit, 54 Electric device controller, 56 Third winding, 60p, 66p Positive terminal, 60n, 66n Negative terminal, 62, 64 Coupling element, 65 Antenna, 70p Positive output terminal, 70n Negative output terminal, 81 , 83, 90 subtractor, 82, 85, 91 integrator, 84 adder, 86, 92 limiter, 87, 93 switching signal generator, 100 battery operation system, 102 charge/discharge control device, 104 discharge control device, U, V switching arm, X, Y switching leg, S1 upper switching element, S2 lower switching element, Sg DC grid voltage sensor, Asg DC grid current sensor, Sb battery unit voltage sensor, Sp battery voltage sensor, Asp battery current sensor, Sq output Voltage sensor, Asq output current sensor.

Claims (8)

A charging/discharging device that is connected to a power supply network and performs contactless power transmission with a battery unit containing a battery,
comprising a charging/discharging switching circuit for the contactless power transmission,
Switching that determines a transmission power target value for the battery based on a DC grid voltage given from the power supply network, performs switching of the charge/discharge switching circuit according to the transmission power target value, and controls switching of the battery unit. A charging/discharging device characterized in that a signal is generated according to the transmission power target value, and the switching signal is transmitted to the battery unit by non-contact communication. The charging/discharging device according to claim 1,
a charging/discharging characteristic setting value representing a change in the DC grid voltage with respect to a change in the current flowing through the charging/discharging device;
and a no-load voltage setting value representing the voltage at the connection end to the power supply network when in a no-load state,
A charging/discharging device characterized in that the transmission power target value is determined from the measured value of the DC grid voltage, the charging/discharging characteristic setting value, and the no-load voltage setting value. The charging/discharging device according to claim 1 or 2,
Obtaining a voltage measurement value between terminals of a power storage element included in the battery unit through the non-contact communication,
A charging/discharging device characterized in that the switching signal is generated based on the voltage measurement value and the DC grid voltage measurement value. The charging/discharging device according to claim 3,
A charging/discharging device characterized in that switching is not performed when the voltage measurement value is not acquired through the non-contact communication. The charging/discharging device according to any one of claims 1 to 4,
The battery unit is
A charging/discharging device characterized in that switching is not performed when the switching signal is not acquired through the contactless communication. The charging/discharging device according to any one of claims 1 to 5,
two switching arms connected in parallel, each switching arm comprising two switching elements connected in series;
a winding connected between a series connection point of two switching elements on one of the two switching arms and a series connection point of two switching elements on the other switching arm;
a charge/discharge controller that performs the non-contact communication with the battery unit and switches each of the switching arms;
Equipped with
A charging/discharging device characterized in that the DC grid voltage is applied between two parallel connection points of each switching arm. A battery connecting device that configures the battery unit by connecting the battery and performs the contactless power transmission with the charging/discharging device according to claim 6,
two switching legs connected in parallel, each switching leg comprising two switching elements connected in series;
a second winding connected between a series connection point of two switching elements on one of the two switching legs and a series connection point of two switching elements on the other switching leg;
a battery controller that performs the contactless communication with the charging and discharging device and switches each of the switching legs in accordance with the switching signal;
Equipped with
A battery connection device characterized in that the battery is connected between a tap of the second winding and one of two parallel connection points of each of the switching arms. In a battery connection device that performs contactless power transmission between a battery and a charging/discharging device connected to a power supply network,
two switching legs connected in parallel, each switching leg comprising two switching elements connected in series;
a winding connected between a series connection point of two switching elements on one of the two switching legs and a series connection point of two switching elements on the other switching leg;
A battery controller that performs contactless communication with the charging and discharging device and switching each of the switching legs according to a switching signal obtained from the charging and discharging device through the contactless communication,
A battery connection device characterized in that the battery is connected between a tap of the winding and one of two parallel connection points of each of the switching arms.

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