JP2015119546A - Power conversion device to be used by connection to motor car - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power conversion device capable of supplying desired AC output power to loads without imposing excessive burden on an on-vehicle battery.SOLUTION: A power conversion device 1 includes: a power conversion unit 2 for supplying AC output power to loads R through a service wire 12; and a control unit 3 for controlling the power conversion unit 2 so as to allow a voltage value to be detected by a voltage detection unit 8 to be a target voltage value. The control unit 3 includes: a correction value determination unit 4 for determining the correction value of the target voltage value on the basis of the current value of a current flowing in the service wire 12; and a target voltage resetting unit 6 for determining whether an on-vehicle battery 10 can supply DC power to be required when the voltage value of the AC output power is defined as the sum of the target voltage value and the correction value or not based on information related to the on-vehicle battery 10, setting the sum of them as a new target voltage value when the supply is possible, and setting a value obtained by maximally performing addition to the target voltage value within a suppliable range as a new target voltage value when the supply is impossible.

Description

  The present invention relates to a power conversion device that supplies AC output power obtained by converting DC power supplied from a vehicle-mounted battery of an electric vehicle to various loads such as a household load through a predetermined length of distribution line.

  2. Description of the Related Art In recent years, a power conversion device that can supply AC output power corresponding to commercial AC power to various loads in a house by discharging a vehicle-mounted battery mounted on an electric vehicle such as an electric vehicle and a plug-in hybrid car. It is starting to be used. Such a power conversion device is generally called a Vehicle to Home system (hereinafter referred to as “V2H system”).

  As shown in FIG. 3, the V2H system 20 includes a power conversion unit 21 that supplies AC output power obtained by converting DC power supplied from the in-vehicle battery 10 of the electric vehicle EV to the house H through a predetermined length of the distribution line 12. And a voltage detector 23 for detecting the voltage value of the AC output power at the end of the distribution line 12 on the V2H system 20 side, and the power converter 21 so that the voltage value of the AC output power becomes a predetermined target voltage value. And a control unit 22 for controlling. Moreover, the house H has the power distribution part 13 which receives alternating current output power through the power distribution line 12, and the some load R connected to this.

  According to the V2H system 20, even when a supply of commercial AC power is interrupted, the load R is supplied by supplying the load R with AC output power obtained by converting the DC power supplied from the in-vehicle battery 10 to AC. You can keep it running for a while. Although detailed description is omitted, the V2H system 20 also has a function of charging the in-vehicle battery 10 with commercial AC power. Therefore, the V2H system 20 is charged with the in-vehicle battery 10 with cheap commercial AC power at night, and this is daytime. It is also possible to save electricity charges by using it as AC output power.

  By the way, in this V2H system 20, when the distribution line 12 becomes long to some extent, the voltage value of the AC output power received by the distribution unit 13 of the house H due to the voltage drop due to the electrical resistance of the distribution line 12 becomes lower than the target voltage value. As a result, there arises a problem that the load R cannot be operated normally. With respect to this problem, Patent Document 1 proposes a compensation circuit for compensating for a voltage drop caused by a power supply load line that connects a DC-DC converter corresponding to the power converter 21 and a load. According to the compensation circuit of Patent Document 1, the voltage drop due to the power load line can be compensated by causing the DC-DC converter unit to output a voltage added with the voltage drop.

  However, since the V2H system 20 outputs the AC output power obtained by converting the DC power supplied from the in-vehicle battery 10 as described above, depending on the state of charge of the in-vehicle battery 10 when the voltage value of the AC output power is added, An excessive load is applied to the in-vehicle battery 10, and the battery management unit (commonly called BMU) 11 may stop discharging the in-vehicle battery 10. When the discharge of the in-vehicle battery 10 is stopped, the supply of the AC output power to the load R is immediately stopped, so that compensation can be performed, which adversely affects the operation of the load R.

Japanese Utility Model Publication No. 5-23214

  This invention is made | formed in view of the said situation, The place made into the subject is the power converter device which can supply desired alternating current output power to load, without overloading a vehicle-mounted battery. It is to provide.

  In order to solve the above-described problems, a power conversion device according to the present invention is a power conversion unit that supplies alternating current output power obtained by converting direct current power supplied from a vehicle-mounted battery of an electric vehicle to a load through a distribution line having a predetermined length. And a voltage detection unit that detects the voltage value of the AC output power at the end of the power distribution unit side of the distribution line, and a control unit that controls the power conversion unit so that the voltage value becomes the target voltage value The conversion device further includes a current detection unit that detects a current value flowing through the distribution line, and the control unit determines a correction value for determining a correction value for the target voltage value based on the current value detected by the current detection unit. A communication unit that communicates with the electric vehicle to obtain information about the in-vehicle battery, and the in-vehicle battery supplies the DC power required when the voltage value of the AC output power is the sum of the target voltage value and the correction value. Whether it can be supplied Judgment is made based on the information about the in-vehicle battery acquired by the communication unit, and if the supply is possible, the sum of the target voltage value and the correction value is set to a new target voltage value. A target voltage resetting unit that sets the target voltage value that has been added as much as possible within the range that can be supplied as a new target voltage value, and a power conversion unit that sets the AC output power voltage value to the new target voltage value A power conversion control unit for controlling

  According to this configuration, the target voltage resetting unit calculates the sum of the original target voltage value and the correction value that can compensate for the voltage drop due to the distribution line only when the on-vehicle battery is not overloaded. In other cases, a new target voltage value is added to the original target voltage value as much as possible in a range where an excessive load is not applied to the in-vehicle battery (that is, a range in which the in-vehicle battery can be supplied). Since the power conversion control unit controls the power conversion unit according to the set new target voltage value, it avoids an excessive burden on the in-vehicle battery and is close to the desired AC output power. AC output power can be supplied to the load.

  The term “maximum” is not limited to the meaning of “up to the maximum”, but also includes the meaning of “up to the maximum”.

  Here, the target voltage resetting unit determines whether or not the in-vehicle battery and the power conversion unit can supply the necessary power when the voltage value of the AC output power is the sum of the target voltage value and the correction value. Judgment is made based on both information related to the in-vehicle battery and information related to the power conversion unit.If supply is possible, the sum of the target voltage value and the correction value is set to a new target voltage value. It is preferable to set a new target voltage value that is the maximum addition of the target voltage value within a range that can be supplied by the in-vehicle battery and the power conversion unit. According to this configuration, it is possible to prevent an excessive load from being applied to the vehicle-mounted battery and to prevent damage to the components of the power conversion unit due to the addition of the target voltage value.

  It is preferable that the correction value determination unit of the power converter determines a correction value based on a relationship between a predetermined current value and a correction value.

  ADVANTAGE OF THE INVENTION According to this invention, the power converter device which can supply desired alternating current output power to load, without putting an excessive burden on a vehicle-mounted battery can be provided.

It is a block diagram which shows the use condition of the power converter device which concerns on this invention. It is a flowchart which shows operation | movement of the power converter device which concerns on this invention. It is a block diagram which shows the use condition of the conventional power converter device.

  Hereinafter, embodiments of a power conversion device according to the present invention will be described with reference to the accompanying drawings.

  The power conversion device 1 according to the present invention can supply AC output power corresponding to commercial AC power to various loads R in the house H by discharging the in-vehicle battery 10 mounted on the electric vehicle EV. Used as a system. As shown in FIG. 1, the power conversion device 1 includes a power conversion unit 2, a control unit 3, a voltage detection unit 8, and a current detection unit 9. Moreover, the house H has the power distribution part 13 which receives alternating current output power through the power distribution line 12, and the some load R connected to this.

  The power conversion unit 2 is an inverter circuit including a plurality of switching elements. The power conversion unit 2 supplies an AC output voltage obtained by converting DC power supplied from the in-vehicle battery 10 to the house H through a distribution line 12 having a predetermined length. ON / OFF of the plurality of switching elements is controlled by a power conversion control unit 7 described later.

The voltage detection unit 8 detects the voltage value of the AC output voltage at the end of the distribution line 12 on the power conversion device 1 side. In the present embodiment, the voltage detector 8 detects the effective voltage value v _rms of the AC output voltage at regular intervals. The voltage detection unit 8 sends a signal Sv corresponding to the detected voltage effective value v _rms to the power conversion control unit 7 described later.

The current detection unit 9 detects the current value of the current flowing through the distribution line 12. In the present embodiment, the current detection unit 9 detects the current effective value i _rms of the current flowing through the distribution line 12 at regular intervals. The current detection unit 9 sends a signal Si corresponding to the detected current effective value i _rms to the correction value determination unit 4 described later.

The control unit 3 controls the power conversion unit 2 so that the voltage value (voltage effective value v _rms ) of the AC output voltage becomes the target voltage value. As shown in FIG. A communication unit 5, a target voltage resetting unit 6, and a power conversion control unit 7 are included. The control unit 3 of the present embodiment is a microprocessor (MPU, Micro-Processing Unit), and the functions of each unit included in the control unit 3 are realized by a program executed on the microprocessor.

The correction value determination unit 4 receives the signal Si corresponding to the current effective value i _rms sent from the current detection unit 9, and determines a correction value that can compensate for the voltage drop in the distribution line 12 based on the current effective value i _rms. To do. In this embodiment, the correction value determination unit 4 determines a correction value by referring to a correspondence table created experimentally in advance. An example of the correspondence table is shown below.

The correction value determination unit 4 may determine the correction value with reference to a table corresponding to the length of the distribution line 12 to be used among a plurality of correspondence tables when the lengths of the distribution lines 12 are different. Specifically, the correction value determination unit 4 is a first correspondence table showing the relationship between the current effective value i _rms and the correction value when the length of the distribution line 12 is 1 m, and the second correspondence showing the relationship in the case of 2 m. The correction value may be determined with reference to either the table or the third correspondence table showing the relationship in the case of 3 m. Further, the correction value determination unit 4 may use a product (= r × i _rms ) of the known resistance value r of the distribution line 12 and the current effective value i _rms as the correction value.

  The communication unit 5 periodically communicates with the battery management unit 11 that manages the in-vehicle battery 10 to acquire the latest information regarding the in-vehicle battery 10. The information acquired by the battery management unit 11 includes, for example, the maximum discharge power, the maximum discharge current, and the state of charge (SOC) of the in-vehicle battery 10. The battery management unit 11 is configured such that when the discharge power of the in-vehicle battery 10 (DC power supplied to the power conversion unit 2) exceeds the maximum discharge power, the discharge current of the in-vehicle battery 10 exceeds the maximum discharge current, and It has a protection function for stopping the discharge of the in-vehicle battery 10 when the charge state of the in-vehicle battery 10 falls below a predetermined threshold.

  The in-vehicle battery 10 supplies the DC power necessary for the target voltage resetting unit 6 when the voltage value of the AC output voltage is the sum of the original target voltage value and the correction value determined by the correction value determining unit 4. Determine whether it is possible. In other words, the target voltage resetting unit 6 determines whether the power supply capability of the in-vehicle battery 10 has enough power to supply DC power necessary to compensate for the voltage drop caused by the distribution line 12. The target voltage resetting unit 6 makes this determination based on the latest information of the in-vehicle battery 10 acquired by the communication unit 5.

  When the in-vehicle battery 10 can supply sufficient DC power to compensate for the voltage drop, the target voltage resetting unit 6 adds the original target voltage value and the correction value determined by the correction value determining unit 4. Is set to a new target voltage value. On the other hand, when the in-vehicle battery 10 cannot supply sufficient DC power, the target voltage resetting unit 6 sets the correction value determined by the correction value determining unit 4 within a range that the in-vehicle battery 10 can supply. The new target voltage value is set by adding the original target voltage value to the maximum.

The power conversion control unit 7 receives the signal Sv corresponding to the voltage effective value v _rms sent from the voltage detection unit 8 and the new target voltage value set by the target voltage resetting unit 6, and receives the voltage effective value v The switching element of the power conversion unit 2 is controlled so that _rms becomes the new target voltage value. In the present embodiment, the power conversion control unit 7 performs voltage effective by PWM control that changes the duty ratio of the control signal for controlling the switching element in accordance with the deviation between the new target voltage value and the voltage effective value v _rms. The value v _rms is matched to the new target voltage value.

  When the sum of the original target voltage value and the correction value is set to a new target voltage value, the voltage drop in the distribution line 12 is completely compensated by the PWM control by the power conversion control unit 7, and the distribution line 12 The voltage value of the AC output power at the end on the house H side matches the original target voltage value. Since there is a surplus in the power supply capability of the in-vehicle battery 10, the battery management unit 11 does not detect an abnormality and stop the discharge of the in-vehicle battery 10.

  On the other hand, when the power supply capability of the in-vehicle battery 10 is not sufficient, when the original target voltage value is added to the maximum within the range that the in-vehicle battery 10 can supply, the new target voltage value is set. The voltage drop in the distribution line 12 is not completely compensated, and the voltage value of the AC output power at the end of the distribution line 12 on the house H side is lower than the original target voltage value. However, even in this case, the voltage value of the AC output power received by the house H is higher than when no compensation is performed, so that the load R in the house H does not operate normally. It can prevent as much as possible.

  Next, the operation flow of the power conversion device 1 will be described with reference to FIG.

When the power conversion unit 2 starts supplying AC output power, the voltage detection unit 8 detects the effective voltage value v _rms in step S1, the current detection unit 9 detects the effective current value i _rms in step S2, and further includes a step In S <b> 3, the communication unit 5 acquires information on the in-vehicle battery 10. Steps S1 to S3 may be executed by changing the order.

  Next, in step S4, the correction value determination unit 4 determines the correction value, and in step S5, whether or not the target voltage resetting unit 6 can correct with the correction value, that is, the in-vehicle battery 10 has sufficient remaining capacity. It is determined whether or not. If the correction is possible, the target voltage resetting unit 6 sets the sum of the original target voltage value and the correction value as a new target voltage value (step S6). On the other hand, when the correction is impossible, the target voltage resetting unit 6 sets a value obtained by adding the original target voltage value to the maximum within the range that can be supplied by the in-vehicle battery 10 as a new target voltage value (step S7). ).

  Next, the power conversion control unit 7 controls the power conversion unit 2 according to the new target voltage value (step S8).

  The power conversion device 1 repeatedly executes the above steps S1 to S8 while supplying the load R with AC output power obtained by converting the DC power supplied from the in-vehicle battery 10 to AC.

  As mentioned above, although the Example of the power converter device 1 which concerns on this invention was described, the structure of this invention is not limited to the structure of the said Example.

For example, in the above embodiment, the voltage detection unit 8 detects the voltage effective value v _rms and the current detection unit 9 detects the current effective value i _rms , but instead of the effective value, an instantaneous value or an average value is detected. Also good.

Moreover, in the said Example, although the electric current detection part 9 detected the electric current (current effective value _irms ) which flows through the distribution line 12 directly, AC output electric power is output in the edge part by the side of the power conversion part 2 of the distribution line 12. The current value flowing through the distribution line 12 may be detected from the output power value and the output voltage value detected by the voltage detector 8.

  Moreover, in the said Example, it determines based on the information regarding a vehicle-mounted battery whether the vehicle-mounted battery can supply direct-current power required when the voltage value of AC output power is made into the sum of a target voltage value and a correction value. However, based on both the information on the in-vehicle battery and the information on the power conversion unit, it is determined whether or not each of the in-vehicle battery and the power conversion unit can supply necessary power. If the sum with the correction value is set to a new target voltage value and cannot be supplied, the new target voltage is set by adding the maximum target voltage value within the range that can be supplied by the in-vehicle battery and the power converter. It may be set to a value. As information from the power conversion unit, for example, withstand voltage of components constituting the inverter circuit can be cited. By resetting the target voltage value as described above, it is possible to prevent an excessive load from being applied to the on-vehicle battery and to prevent the components of the power conversion unit from being damaged.

DESCRIPTION OF SYMBOLS 1 Power converter 2 Power converter 3 Control part 4 Correction value determination part 5 Communication part 6 Target voltage resetting part 7 Power conversion control part 8 Voltage detection part 9 Current detection part 10 Car-mounted battery 11 Battery management unit 12 Distribution line 13 Distribution Department EV Electric car H Housing R Load

Claims (3)

A power conversion unit that supplies AC output power obtained by converting DC power supplied from an on-vehicle battery of an electric vehicle to a load through a predetermined length of distribution line, and the AC at the end of the distribution line on the power conversion unit side A power conversion device comprising: a voltage detection unit that detects a voltage value of output power; and a control unit that controls the power conversion unit so that the voltage value becomes a target voltage value,
A current detection unit for detecting a current value flowing through the distribution line;
The controller is
A correction value determination unit that determines a correction value of the target voltage value based on the current value detected by the current detection unit;
A communication unit that communicates with the electric vehicle to obtain information about the in-vehicle battery;
Regarding the in-vehicle battery acquired by the communication unit whether or not the in-vehicle battery can supply the DC power required when the voltage value of the AC output power is the sum of the target voltage value and the correction value If it is determined based on the information and can be supplied, the sum of the target voltage value and the correction value is set to a new target voltage value. A target voltage resetting unit that sets a target voltage value that is the maximum addition of the target voltage value to a new target voltage value;
A power conversion control unit that controls the power conversion unit so that the voltage value of the AC output power becomes the new target voltage value;
The power converter device characterized by including.   If the voltage value of the AC output power is the sum of the target voltage value and the correction value, can the target voltage resetting unit supply the necessary power for each of the in-vehicle battery and the power conversion unit? Determining whether or not based on both the information on the in-vehicle battery and the information on the power conversion unit, if it can be supplied, set the sum of the target voltage value and the correction value to a new target voltage value, 2. When the supply is impossible, a value obtained by adding the target voltage value to the maximum within a range that can be supplied by the in-vehicle battery and the power conversion unit is set as a new target voltage value. The power converter device described in 1.   The power conversion apparatus according to claim 1, wherein the correction value determination unit determines the correction value based on a predetermined relationship between the current value and the correction value.

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