Charging device

Abstract

To charge an electric vehicle without excess suppression of charging current.SOLUTION: A charging device 21 has an excess determination part 211 estimating the value of a current flowing through a plurality of electric facilities from the resistance between the plurality of electric facilities in a facility to which an electric vehicle 2 is connected and fluctuation of charging terminal voltage at the time of charging the electric vehicle 2, and determining whether or not the sum of currents flowing through the plurality of electric facilities exceeds a threshold current, and a charging control part 212 limiting the charging of the electric vehicle 2 based on a determination result from the excess determination part 211.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a charging device. [Background technology]

[0002] The charging device described in the following patent document detects the voltage of the input power source when charging the battery of a power tool, and reduces the charging current according to the voltage drop. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-129619 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, the charging current is reduced when the input voltage falls below a predetermined value, so the relationship between the input voltage and the upper limit of the charging current is uniform, and the charging current may be reduced even when it is not actually necessary to reduce it.

[0005] The present disclosure aims to charge electric vehicles without excessive constraints. [Means for solving the problem]

[0006] The present disclosure provides a charging device that includes an excess determination unit that estimates the value of the current flowing through a plurality of pieces of electrical equipment from the resistance between the pieces of electrical equipment in a facility to which an electric vehicle is connected and fluctuations in the charging terminal voltage when the electric vehicle is being charged, and determines whether the sum of the currents flowing through the plurality of pieces of electrical equipment exceeds a threshold current, and a charging control unit that restricts the charging of the electric vehicle based on the determination result of the excess determination unit. [Effects of the Invention]

[0007] According to the present disclosure, charging can be performed without excessive suppression. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a system configuration diagram for explaining a charging device according to this embodiment. [Figure 2] FIG. 2 is a flowchart for explaining the operation of the charging device according to this embodiment. [Figure 3] FIG. 3 is a flowchart for explaining the operation of the charging device according to this embodiment. [Figure 4] FIG. 4 is a graph showing an example of the relationship between the actually measured voltage and the estimated current. [Figure 5] FIG. 5 is a flowchart for explaining the operation of the charging device according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, the present embodiment will be described with reference to the accompanying drawings. To facilitate understanding of the description, the same components in the drawings will be denoted by the same reference numerals as much as possible, and duplicated descriptions will be omitted.

[0010] A charging device 21 according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a system configuration diagram for explaining the state when charging an electric vehicle 2 equipped with the charging device 21. The electric vehicle 2 is charged by inserting a charging plug 22 into a charging outlet 58 connected to a safety breaker 37 in a distribution board 3 installed within the facility.

[0011] The distribution board 3 is equipped with a contract breaker 31, a ground fault circuit breaker 32, and safety breakers 33, 34, 35, 36, and 37. The contract breaker 31 is a breaker configured to interrupt the circuit when a current greater than the amount of current contracted with the electric power company flows. The ground fault circuit breaker 32 is a breaker configured to interrupt the circuit when a ground fault occurs. The safety breakers 33, 34, 35, 36, and 37 are breakers configured to interrupt the circuit when a current greater than the amount of current specified for each breaker flows.

[0012] Electricity sent to the contract breaker 31 is sent to the earth leakage breaker 32. Extending from the earth leakage breaker 32 are a voltage line LR, a neutral line LN, and a voltage line LB. The voltage to ground of the neutral line LN is 0V. The line voltage between the neutral line LN and the voltage line LR is 100V. The line voltage between the neutral line LN and the voltage line LB is 100V. The line voltage between the voltage line LR and the voltage line LB is 200V.

[0013] Safety breakers 33 and 34 are connected to the voltage line LR and the neutral line LN, and therefore supply 100 V power. Safety breakers 35, 36, and 37 are connected to the voltage line LR and the voltage line LB, and therefore supply 200 V power.

[0014] Safety breaker 33 supplies power to outlet 51 and room light 53. For example, a hair dryer 52 is connected to outlet 51 when in use. Hair dryer 52 and room light 53 connected to outlet 51 are also referred to as load La. Safety breaker 34 supplies power to microwave oven 54 and refrigerator 55. Microwave oven 54 and refrigerator 55 are also referred to as load Lb.

[0015] The safety breaker 35 supplies power to an induction cooking heater 56. The safety breaker 36 supplies power to an air conditioner 57. The safety breaker 37 supplies power to a charging outlet 58.

[0016] Charging terminal voltage V of charging outlet 58 can be calculated by subtracting the voltage drop caused by using each device from 200 V, which is the voltage at earth leakage breaker 32, and can be expressed by the following equation (f01). V=200-(a+b+c+d)p-(b+c+d)q-(c+d)p-(c+d)q-2(c+d)r-2ds...(f01)

[0017] In equation (f01), "p" is the resistance value of the voltage line LR from the part where the earth leakage breaker 32 is connected to the safety breaker 33. "q" is the resistance value of the voltage line LR from the part where the safety breaker 33 is connected to the part where the safety breaker 34 is connected. "r" is the resistance value of the voltage line LR from the part where the safety breaker 34 is connected to the part where the safety breaker 35 is connected. "s" is the resistance value of the voltage line LR from the part where the safety breaker 35 is connected to the part where the safety breaker 36 is connected. In this embodiment, the voltage lines LR and LB are equivalent and have the same resistance value per unit length.

[0018] In equation (f01), "a" is a current value indicating the current that flows when load La is used. Since load La is composed of dryer 52 and interior light 53, the current value "a52" that flows through dryer 52 and the current value "a53" that flows through interior light 53 may be separately calculated, and "a" may be the sum of "a52" and "a53."

[0019] "b" is a current value indicating the current that flows when load Lb is used. Since load Lb is made up of microwave oven 54 and refrigerator 55, the current value "b54" flowing through the microwave oven and the current value "b55" flowing through refrigerator 55 may be recorded separately, and "b" may be the sum of "b54" and "b55."

[0020] "c" is the current value that indicates the current that flows when IH cooking heater 56 is in use. "d" is the current value that indicates the current that flows when air conditioner 57 is in use. The current values "a", "b", "c", and "d" vary depending on the usage of each device, but can be estimated by monitoring the charging terminal voltage V using equation (f01).

[0021] For example, when only interior light 53 is used, the value of "a" falls within a certain range, and "b," "c," and "d" are zero, so the value of charging terminal voltage V can be determined to be within a certain range. Similarly, when interior light 53 and air conditioner 57 are used, the values of "a" and "d" fall within a certain range, and "b" and "c" are zero, so the value of charging terminal voltage V can be determined to be within a certain range. In this way, it is possible to determine what value charging terminal voltage V will have depending on which device is used. If this relationship is transmitted and stored in some way to charging device 21, the degree and magnitude of "a," "b," "c," and "d" can be estimated by monitoring charging terminal voltage V.

[0022] The charging device 21 is mounted on the electric vehicle 2. The charging device 21 is a device that detects whether the charging plug 22 is inserted into the charging outlet 58, and controls charging of the battery mounted on the electric vehicle 2.

[0023] The charging device 21 includes an excess determination unit 211 and a charging control unit 212. The excess determination unit 211 estimates current values "a", "b", "c", and "d" flowing through the multiple pieces of electrical equipment from resistance values "p", "q", "r", and "s" between multiple pieces of electrical equipment in the facility to which the electric vehicle 2 is connected and fluctuations in the charging terminal voltage when the electric vehicle 2 is being charged. The excess determination unit 211 determines whether the sum of the current values "a", "b", "c", and "d" flowing through the multiple pieces of electrical equipment exceeds a threshold value. The charging control unit 212 restricts charging of the electric vehicle based on the determination result of the excess determination unit 211.

[0024] Specific operations of charging device 21 will be described with reference to Fig. 2. When charging plug 22 is inserted into charging outlet 58, charging control unit 212 starts charging, and the process of step S01 begins. In step S01, excess determination unit 211 measures charging terminal voltage V of charging outlet 58. In step S02 following step S01, excess determination unit 211 executes excess determination processing to determine whether or not the total current consumption exceeds the contracted current.

[0025] The excess current determination process in step S02 will be described with reference to Fig. 3. In step S11, excess current determination unit 211 estimates total current consumption Iest_total. Total current consumption Iest_total is estimated by estimating current values "a," "b," "c," and "d" used by each device from charging terminal voltage V of charging outlet 58, as described above.

[0026] In step S12 following step S11, the excess determination unit 211 determines whether the total current consumption Iest_total exceeds the threshold current Ith. The threshold current Ith is set to a value smaller than the contracted current. The threshold current Ith may be set to the same value as the contracted current. If the excess determination unit 211 determines that the total current consumption Iest_total exceeds the threshold current Ith (step S12: YES), the process proceeds to step S13. If the excess determination unit 211 determines that the total current consumption Iest_total does not exceed the threshold current Ith (step S12: NO), the excess determination process ends, and the process proceeds to step S03 in FIG. 2. In this case, the contracted current excess flag is set to "0."

[0027] In step S13, the excess determination unit 211 sets the contract current excess flag to "1." In step S14 following step S13, it is determined whether the state in which the total current consumption Iest_total exceeds the threshold current Ith continues. If the state in which the total current consumption Iest_total exceeds the threshold current Ith continues (step S14: YES), the process repeats step S14. If the state in which the total current consumption Iest_total exceeds the threshold current Ith does not continue (step S14: NO), the process proceeds to step S15.

[0028] In step S15, the excess determination unit 211 sets the contract current excess flag to 0. When the process of step S15 ends, the excess determination process ends.

[0029] When the excess determination process described with reference to Fig. 3 is completed, the process proceeds to step S03 in Fig. 2. In step S03, the charging control unit 212 determines whether the contract current excess flag is set to "1". If the contract current excess flag is set to "1" (step S03: YES), the process proceeds to step S04. If the contract current excess flag is not set to "1" (step S03: NO), charging control by the charging control unit 212 continues, and the process ends when a predetermined condition is satisfied.

[0030] In step S04, the charging control unit 212 stops charging. In step S05 following step S04, it is determined whether the contract current excess flag is set to "1". If the contract current excess flag is set to "1" (step S05: YES), the process repeats step S05. If the contract current excess flag is not set to "1" (step S05: NO), the process proceeds to step S06. In step S06, charging control by the charging control unit 212 is resumed, and the process ends when a predetermined condition is satisfied.

[0031] An example of the relationship between the voltage of charging outlet 58 and total current consumption Iest_total will be described with reference to Fig. 4. In Fig. 4(A), the vertical axis represents estimated total current consumption Iest_total, and the horizontal axis represents time. In Fig. 4(B), the vertical axis represents actually measured voltage of charging outlet 58, and the horizontal axis represents time.

[0032] At time 0, charging plug 22 is inserted into charging outlet 58, and charging by charging device 21 begins. At time t1, interior light 53 is turned on, and the charging terminal voltage of charging outlet 58 drops. As described in step S11 of FIG. 3 , excess determination unit 211 estimates total current consumption Iest_total. Because only interior light 53 is turned on, the estimated total current consumption Iest_total is smaller than threshold current Ith.

[0033] At time t2, hair dryer 52 is used in addition to interior light 53, and the charging terminal voltage of charging outlet 58 drops. In this case as well, excess determination unit 211 estimates total current consumption Iest_total. The estimated total current consumption Iest_total is smaller than threshold current Ith.

[0034] At time t3, air conditioner 57 is used in addition to interior light 53 and hair dryer 52, and the charging terminal voltage of charging outlet 58 drops. In this case, excess determination unit 211 also estimates total current consumption Iest_total. The estimated total current consumption Iest_total is smaller than threshold current Ith.

[0035] At time t4, IH cooking heater 56 is further used, and the charging terminal voltage of charging outlet 58 further drops. In this case, too, excess determination unit 211 estimates total current consumption Iest_total. The estimated total current consumption Iest_total exceeds threshold current Ith immediately after time t4. As a result, as described in steps S12 and S13 of FIG. 3, the contract current excess flag becomes "1." Accordingly, charging by charging device 21 is stopped, as described in steps S03 and S04 of FIG. 2.

[0036] At time t5, use of the IH cooking heater 56 ends, and the charging terminal voltage of the charging outlet 58 rises. In this case, too, the excess determination unit 211 estimates the total current consumption Iest_total. The estimated total current consumption Iest_total falls below the threshold current Ith immediately after time t5. As a result, as described in steps S14 and S15 of FIG. 3, the contract current excess flag becomes "0." Accordingly, charging by the charging device 21 resumes, as described in steps S05 and S06 of FIG. 2.

[0037] In the above description, the threshold current Ith is set to a value smaller than the contract current in the excess determination process, and charging by the charging device 21 is stopped when the estimated total current consumption Iest_total approaches the contract current. However, the manner in which charging is stopped is not limited to this, and charging by the charging device 21 may be stopped within several seconds when the estimated total current consumption Iest_total exceeds the contract current.

[0038] Furthermore, in the excess determination process, if the charging terminal voltage of charging outlet 58 suddenly decreases, it may be determined that the total current consumption Iest_total has suddenly increased, and charging by charging device 21 may be stopped. This excess determination process will be described with reference to FIG. 5.

[0039] The excess determination process based on a sudden voltage drop will be described with reference to Fig. 5. In step S21, excess determination unit 211 calculates charging terminal voltage gradient ΔV of charging outlet 58.

[0040] In step S22 following step S21, excess determination unit 211 determines whether ΔV<0 and |ΔV|>ΔVth, where ΔVth is the threshold slope of the charging terminal voltage. In step S21, the charging terminal voltage slope ΔV is negative (decreasing) and the absolute value of the charging terminal voltage slope ΔV is greater than the predetermined threshold slope ΔVth, thereby determining that the charging terminal voltage slope ΔV has suddenly decreased.

[0041] If the excess determination unit 211 determines that the charging terminal voltage gradient ΔV is decreasing rapidly (step S22: YES), the process proceeds to step S23. If the excess determination unit 211 determines that the charging terminal voltage gradient ΔV is not decreasing rapidly (step S22: NO), the excess determination process ends, and the process proceeds to step S03 in Fig. 2. In this case, the contract current excess flag is set to "0".

[0042] In step S23, the excess determination unit 211 sets the contract current excess flag to "1." In step S24 following step S23, the excess determination unit 211 performs a determination of a sudden decrease in the charging terminal voltage gradient ΔV, similar to step S22. If the excess determination unit 211 determines that the charging terminal voltage gradient ΔV is continuing to decrease suddenly (step S24: YES), the process repeats step S24. If the excess determination unit 211 determines that the charging terminal voltage gradient ΔV is not continuing to decrease suddenly (step S24: NO), the process proceeds to step S25. Note that in step S24, the determination in step S14 of FIG. 3 may also be performed, and the process may proceed to step S25 if both conditions are met.

[0043] In step S25, the excess determination unit 211 sets the contract current excess flag to “0.” When the process of step S25 ends, the excess determination process ends.

[0044] As described above, the charging device 21 according to this embodiment is mounted on the electric vehicle 2, but as long as it is a chargeable electric vehicle, it may be a BEV that is powered only by a battery or a PHEV that is also powered by an engine.

[0045] The charging device 21 according to this embodiment includes an excess determination unit 211 that estimates current values "a," "b," "c," and "d" flowing through the plurality of electrical equipment from resistance values "p," "q," "r," and "s" between the plurality of electrical equipment in the facility to which the electric vehicle 2 is connected and fluctuations in the charging terminal voltage when the electric vehicle 2 is being charged, and determines whether the sum of the currents flowing through the plurality of electrical equipment exceeds a threshold current, and a charging control unit 212 that restricts the charging of the electric vehicle 2 based on the determination result of the excess determination unit 211.

[0046] According to the charging device 21, the relationship between the input voltage and the upper limit of the charging current is not uniform, but rather current values "a", "b", "c", and "d" flowing through multiple electrical equipment are estimated from fluctuations in the charging terminal voltage when the electric vehicle 2 is being charged, thereby enabling charging without excessive suppression.

[0047] The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Design modifications to these specific examples made by a person skilled in the art as appropriate are also included within the scope of the present disclosure as long as they comprise the features of the present disclosure. The elements of the above-described specific examples, as well as their arrangement, conditions, shape, etc., are not limited to those exemplified and can be modified as appropriate. The elements of the above-described specific examples can be combined in various ways as appropriate, as long as no technical contradictions arise.

[0048] The charging device and method described herein may be implemented by a special-purpose computer configured with a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the charging device and method described herein may be implemented by a special-purpose computer configured with a processor configured with one or more dedicated hardware logic circuits. Alternatively, the charging device and method described herein may be implemented by one or more special-purpose computers configured with a processor and memory programmed to perform one or more functions in combination with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory storage medium. [Explanation of symbols]

[0049] 2: Electric vehicles 21:Charging device 211: Excess judgment section 212: Charging control unit 22: Charging plug 3: Distribution board 31: Contract breaker 32:Earth leakage breaker 33, 34, 35, 36, 37: Safety breaker LR, LB: Voltage line LN: Neutral conductor

Claims

[Claim 1] an excess determination unit that estimates a current value flowing through a plurality of pieces of electrical equipment in a facility to which the electric vehicle is connected based on a resistance value between the pieces of electrical equipment and a fluctuation in a charging terminal voltage when the electric vehicle is being charged, and determines whether the sum of the currents flowing through the plurality of pieces of electrical equipment exceeds a threshold current; a charging control unit that limits charging of the electric vehicle based on a determination result of the excess determination unit.

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