Power control device
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- PANASONIC AUTOMOTIVE SYST CO LTD
- Filing Date
- 2025-01-24
- Publication Date
- 2026-08-05
Smart Images
Figure 2026126847000001_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to a power control device.
Background Art
[0002] Patent Document 1 discloses an in-vehicle charger that controls charging of a battery.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] When the battery voltage or AC voltage fluctuates during the charging operation, or when the load current fluctuates during the discharging operation, the in-vehicle charger of Patent Document 1 stops charging or discharging by detecting abnormal operations such as overcurrent and overvoltage. When charging or discharging is stopped, problems such as a drop in charging power until restart and the power supply of the load being used during discharging stopping occur. Therefore, it has been desired to perform control to continue charging and discharging.
[0005] An object of this disclosure is to provide a power control device that can continue operating without stopping the charging and discharging operations even when a voltage fluctuation or a load current fluctuation occurs.
Means for Solving the Problems
[0006] The power control device according to this disclosure includes: an AC-DC converter having a first input terminal and a first output terminal, which converts the AC voltage of an AC power source connected to the first input terminal into a DC voltage and outputs it from the first output terminal, or converts the DC voltage input to the first output terminal into an AC voltage and supplies it to a load connected to the first input terminal instead of the AC power source; a DC-DC converter having a second input terminal and a second output terminal, which boosts or de-voltages the DC voltage from the first output terminal of the AC-DC converter connected to the second input terminal to charge a battery connected to the second output terminal, or de-voltages or boosts the DC voltage of the battery and outputs it from the second input terminal; and when the battery is in a charging state, the BUS voltage, which is the voltage at the first output terminal, fluctuates, causing the operation of the power control device to stop. The power control unit is characterized by comprising: a power control unit that, when the BUS voltage becomes smaller than a first threshold greater than a devoltage threshold that causes the power control unit to stop operating, or larger than a second threshold that causes the power control unit to stop operating, adjusts the charging current command value to the DC-DC converter or adjusts the PFC current command value to the AC-DC converter to give a command to keep the BUS voltage within a first predetermined range; and when the battery is supplying power to the load, and the current flowing through the load fluctuates, causing the BUS voltage to become smaller than a third threshold greater than a devoltage threshold that causes the power control unit to stop operating, or larger than a fourth threshold that causes the power control unit to stop operating, adjusts the discharge power command value to be supplied to the DC-DC converter to give a command to keep the BUS voltage within a second predetermined range. [Effects of the Invention]
[0007] According to the power control device described herein, even if voltage fluctuations or load current fluctuations occur, the device can continue to operate without stopping the charging and discharging operation. [Brief explanation of the drawing]
[0008] [Figure 1] Figure 1 shows an example of a schematic configuration when using the on-board charger according to the embodiment in a charging state. [Figure 2] Figure 2 shows an example of a schematic configuration when using the on-board charger according to this embodiment in a discharge state. [Figure 3] Figure 3 is a functional block diagram showing an example of the functional configuration of the controller included in the in-vehicle charger according to this embodiment. [Figure 4] Figure 4 is a flowchart showing an example of the processing flow performed by the in-vehicle charger according to this embodiment. [Figure 5] Figure 5 shows an example of a timing chart for operation control performed by the on-board charger according to the embodiment when the AC voltage drops sharply beyond a predetermined fluctuation rate during charging operation. [Figure 6] Figure 6 is a flowchart showing an example of the processing flow performed by the on-board charger according to the embodiment when the AC voltage drops sharply beyond a predetermined fluctuation rate during charging operation. [Figure 7] Figure 7 shows an example of a timing chart for operation control performed by the on-board charger according to the embodiment when the battery voltage rises sharply and exceeds a predetermined fluctuation rate during charging. [Figure 8] Figure 8 is a flowchart showing an example of the processing flow performed by the on-board charger according to the embodiment when the battery voltage rises sharply beyond a predetermined fluctuation rate during charging operation. [Figure 9] Figure 9 shows an example of a timing chart for control performed by the on-board charger according to the embodiment when the battery voltage drops sharply beyond a predetermined fluctuation rate during charging operation. [Figure 10] Figure 10 is a flowchart showing an example of the processing flow performed by the on-board charger according to the embodiment when the battery voltage drops sharply beyond a predetermined fluctuation rate during charging operation. [Figure 11]Figure 11 shows an example of a timing chart for operation control performed by the on-board charger according to the embodiment when the load current drops sharply beyond a predetermined fluctuation rate during discharge operation. [Figure 12] Figure 12 is a flowchart showing an example of the processing flow performed by the on-board charger according to the embodiment when the load current drops sharply beyond a predetermined fluctuation rate during discharge operation. [Figure 13] Figure 13 shows an example of a timing chart for operation control performed by the on-board charger according to the embodiment when the load current rises sharply and exceeds a predetermined fluctuation rate during discharge operation. [Figure 14] Figure 14 is a flowchart showing an example of the processing flow performed by the on-board charger according to the embodiment when the load current rises sharply beyond a predetermined fluctuation rate during discharge operation. [Modes for carrying out the invention]
[0009] The in-vehicle charger related to this disclosure will be described below with reference to the drawings.
[0010] (Configuration of the on-board charger) The schematic configuration of the on-board charger 20 of the embodiment will be explained using Figures 1 and 2. Figure 1 is a diagram showing an example of the schematic configuration when the on-board charger according to the embodiment is used in a charging state. Figure 2 is a diagram showing an example of the schematic configuration when the on-board charger according to the embodiment is used in a discharging state.
[0011] Since the on-board charger 20 can be used in both charging and discharging states, when describing the on-board charger 20 used in the charging state, it will be referred to as on-board charger 20a (see Figure 1), and when describing the on-board charger 20 used in the discharging state, it will be referred to as on-board charger 20b (see Figure 2). Note that the on-board charger 20 is an example of a power control device in this disclosure.
[0012] The in-vehicle charger 20a charges the battery 14 connected to the output terminals 20r and 20s by the AC power supply 12 connected to the input terminals 20p and 20q. The AC power supply 12 is, for example, a commercial power supply of 100V or 200V. The input terminal 20p is a non-grounded terminal (L), and the input terminal 20q is a grounded terminal (N). The battery 14 is a rechargeable secondary battery such as a lithium-ion battery, for example.
[0013] The in-vehicle charger 20a includes an AC-DC converter 21, a DC-DC converter 22, a controller 23, an ammeter 24, an ammeter 27, a voltmeter 25, a voltmeter 26, and a voltmeter 28.
[0014] The AC-DC converter 21 converts the AC voltage input to the input terminals 21a and 21b into a DC voltage and outputs it from the output terminals 21c and 21d. The input terminals 21a and 21b are an example of the first input terminals in the present disclosure. The output terminals 21c and 21d are an example of the first output terminals in the present disclosure.
[0015] The AC-DC converter 21 has a power factor improvement function (PFC (Power Factor Correction) function). When the AC-DC converter 21 converts the AC voltage into a DC voltage, a phase difference between the voltage and the current occurs. Therefore, a loss of the input power occurs. In order to reduce this power loss, the power factor improvement function is to control so that the phase difference between the voltage and the current becomes as small as possible. The power factor improvement function is realized by adding a known control circuit to the AC-DC converter 21.
[0016] The AC-DC converter 21 operates according to the PFC current command value Ipfc (see FIG. 9) output by the controller 30.
[0017] The DC-DC converter 22 boosts or steps down the DC voltage input to input terminals 22a and 22b and outputs it from output terminals 22c and 22d. Input terminals 22a and 22b are examples of second input terminals in this disclosure. Output terminals 22c and 22d are examples of second output terminals in this disclosure.
[0018] The DC voltage output from output terminals 22c and 22d of the DC-DC converter 22 is applied to the battery 14 connected to output terminals 20r and 20s of the onboard charger 20a, thereby charging the battery 14. Furthermore, when a decrease in the BUS voltage Vbus is detected, the DC-DC converter 22 reduces the charging current Idc of the battery 14 by lowering the charging current command value Itarget (see Figure 5), thereby suppressing the decrease in the BUS voltage Vbus.
[0019] The controller 23 acquires the current and voltage of each part of the onboard charger 20. The controller 23 also determines whether the operating state of the onboard charger 20a is appropriate based on the BUS voltage Vbus, which is the voltage between the output terminals 21c and 21d of the AC-DC converter 21. The onboard charger 20a then controls the charging current command value Itarget to the DC-DC converter 22 to maintain the BUS voltage Vbus within an appropriate range. The controller 23 also controls the PFC current command value Ipfc to the AC-DC converter 21 to maintain the BUS voltage Vbus within an appropriate range. The appropriate range of the BUS voltage Vbus and the detailed control method will be described later (see Figures 5, 7, and 9). Note that the controller 23 is an example of a power control unit in this disclosure.
[0020] The ammeter 24 measures the alternating current Iac, which is the current flowing through the input terminal 22a of the AC-DC converter 21.
[0021] The ammeter 27 measures the charging current Idc, which is the current flowing through the output terminal 22d of the DC-DC converter 22.
[0022] The voltmeter 25 measures the AC voltage Vac, which is the voltage between input terminals 22a and 22b of the AC-DC converter 21.
[0023] The voltmeter 26 measures the BUS voltage Vbus, which is the voltage between output terminals 21c and 21d of the AC-DC converter 21.
[0024] The voltmeter 28 measures the battery voltage Vdc, which is the voltage across the terminals of the battery 14.
[0025] Figure 2 shows a schematic configuration when the onboard charger 20 is used in a discharge state. The onboard charger 20 used in a discharge state is called the onboard charger 20b, as mentioned above. In this case, a load 16 is connected instead of the AC power supply 12 connected to input terminals 20p and 20q in Figure 1. The load 16 is various electrical products such as electric kettles, vacuum cleaners, electric shavers, etc., that operate on AC 100V, which is converted from the DC voltage of the battery 14.
[0026] Since the electrical current flows in the opposite direction to that of the onboard charger 20a, all input terminals on the onboard charger 20a function as output terminals. Conversely, all output terminals on the onboard charger 20a function as input terminals.
[0027] The DC-DC converter 22 of the onboard charger 20b steps down or steps up the DC voltage input to output terminals 22c and 22d and outputs it from input terminals 22a and 22b.
[0028] The DC-DC converter 22 operates according to the discharge power command value Ptarget (see Figure 11) output by the controller 30.
[0029] The AC-DC converter 21 of the onboard charger 20b converts the DC voltage input from output terminals 21c and 21d into AC voltage and outputs it from input terminals 21a and 21b.
[0030] The AC voltage output from input terminals 21a and 21b of the AC-DC converter 21 is applied to the load 16 to drive the load 16.
[0031] The controller 23 of the onboard charger 20b acquires the current and voltage of each part of the onboard charger 20. The controller 23 also determines whether the operating state of the onboard charger 20b is appropriate based on the BUS voltage, which is the voltage between the output terminals 21c and 21d of the AC-DC converter 21. The onboard charger 20b then controls the discharge power command value Ptarget during discharge to the DC-DC converter 22 in order to maintain the BUS voltage within an appropriate range. The detailed control method will be described later (see Figures 11 and 13).
[0032] (Controller Functional Configuration) The functional configuration of the controller 23 in the on-board charger 20 (20a, 20b) will be explained using Figure 3. Figure 3 is a functional block diagram showing an example of the functional configuration of the controller in the on-board charger according to this embodiment.
[0033] The microcomputer built into the controller 23 reads and executes a program stored in its own non-volatile memory, such as ROM. As a result, the controller 23 is configured with the following functional components: an AC voltage measurement unit 31, a battery voltage measurement unit 32, an AC current measurement unit 33, a charging current measurement unit 34, a BUS voltage measurement unit 35, a BUS voltage appropriateness determination unit 36, a charging current command unit 37, a PFC current command unit 38, a discharge power command unit 39, and a charge / discharge state determination unit 40, as shown in Figure 3. Note that some or all of these functional components may be implemented using dedicated hardware.
[0034] The AC voltage measurement unit 31 measures the voltage applied to the voltmeter 25. Specifically, the AC voltage measurement unit 31 measures the AC voltage Vac, which is the voltage between the input terminals 22a and 22b of the AC-DC converter 21.
[0035] Furthermore, the AC voltage measurement unit 31 monitors the AC voltage Vac applied to the voltmeter 25 to determine whether the AC voltage Vac has decreased beyond a predetermined rate of change.
[0036] The battery voltage measurement unit 32 measures the voltage applied to the voltmeter 28. That is, the battery voltage measurement unit 32 measures the battery voltage Vdc, which is the voltage across both ends of the battery 14.
[0037] Furthermore, the battery voltage measurement unit 32 monitors the battery voltage Vdc measured by the voltmeter 28 to determine whether the battery voltage Vdc has risen or fallen beyond a predetermined rate of change.
[0038] The AC current measurement unit 33 measures the current flowing through the ammeter 24. Specifically, the AC current measurement unit 33 measures the AC current Iac, which is the current flowing through the input terminal 22a of the AC-DC converter 21.
[0039] Furthermore, the AC current measurement unit 33 monitors the AC current Iac flowing through the ammeter 24 to determine whether the AC current Iac has risen or fallen beyond a predetermined fluctuation rate. The AC current measurement unit 33 also monitors the AC current Iac flowing through the ammeter 24 to determine whether the AC current Iac has exceeded the AC current limit value Ith (see Figure 5). Alternatively, instead of determining whether the AC current Iac has risen or fallen beyond a predetermined fluctuation rate, it may be determined whether, for example, the BUS voltage Vbus has risen or fallen beyond a predetermined fluctuation rate.
[0040] The charging current measurement unit 34 measures the current flowing through the ammeter 27. That is, the charging current measurement unit 34 measures the charging current Idc, which is the current flowing through the output terminal 22d of the DC-DC converter 22.
[0041] The BUS voltage measurement unit 35 measures the voltage applied to the voltmeter 26. Specifically, the BUS voltage measurement unit 35 measures the BUS voltage Vbus, which is the voltage between the output terminals 21c and 21d of the AC-DC converter 21.
[0042] The BUS voltage appropriateness determination unit 36 determines the relationship between the BUS voltage Vbus measured by the BUS voltage measurement unit 35 and a command value control threshold Vtha that is greater than or equal to the undervoltage threshold Va and greater than the undervoltage threshold Va when the onboard charger 20 (20a) is charging the battery 14. The command value control threshold Vtha is an example of a first threshold in this disclosure. The BUS voltage appropriateness determination unit 36 also determines the relationship between the BUS voltage Vbus measured by the BUS voltage measurement unit 35 and a command value control threshold Vthb that is less than or equal to the overvoltage threshold Vb and less than the overvoltage threshold Vb. The command value control threshold Vthb is an example of a second threshold in this disclosure. Furthermore, the BUS voltage appropriateness determination unit 36 determines whether the BUS voltage Vbus measured by the BUS voltage measurement unit 35 falls between the BUS voltage lower limit Vmina and the BUS voltage upper limit Vmaxa. The lower limit of the BUS voltage Vmina and the upper limit of the BUS voltage Vmaxa are the range in which the BUS voltage Vbus can continue the charging operation of the on-board charger 20a. The range between the lower limit of the BUS voltage Vmina and the upper limit of the BUS voltage Vmaxa is an example of a first predetermined range in this disclosure.
[0043] Furthermore, the BUS voltage appropriateness determination unit 36 determines whether the BUS voltage Vbus measured by the BUS voltage measurement unit 35 is greater than or equal to the undervoltage threshold Vc and less than the command value control threshold Vthc, which is greater than the undervoltage threshold Vc, when the onboard charger 20 (20b) is discharging, i.e., driving the load 16. The command value control threshold Vthc is an example of a third threshold in this disclosure. The BUS voltage appropriateness determination unit 36 also determines whether the BUS voltage Vbus measured by the BUS voltage measurement unit 35 is less than or equal to the overvoltage threshold Vd and greater than the command value control threshold Vthd, which is less than the overvoltage threshold Vd. The command value control threshold Vthd is an example of a fourth threshold in this disclosure. Furthermore, the BUS voltage appropriateness determination unit 36 determines whether the BUS voltage Vbus measured by the BUS voltage measurement unit 35 falls between the BUS voltage lower limit Vminb and the BUS voltage upper limit Vmaxb. The lower limit of the BUS voltage Vminb and the upper limit of the BUS voltage Vmaxb are the range in which the BUS voltage Vbus can continue the discharge operation of the onboard charger 20b. The range between the lower limit of the BUS voltage Vminb and the upper limit of the BUS voltage Vmaxb is an example of a second predetermined range in this disclosure.
[0044] Furthermore, the BUS voltage appropriateness determination unit 36 stops charging the battery 14 when the onboard charger 20 (20a) is charging the battery 14, provided that the BUS voltage Vbus measured by the BUS voltage measurement unit 35 is below the undervoltage threshold Va or above the overvoltage threshold Vb. In addition, the BUS voltage appropriateness determination unit 36 stops discharging when the onboard charger 20 (20b) is driving the load 16, provided that the BUS voltage Vbus measured by the BUS voltage measurement unit 35 is below the undervoltage threshold Vc or above the overvoltage threshold Vd.
[0045] The charging current command unit 37, when the AC voltage Vac of the AC power supply 12 falls below a predetermined fluctuation rate, or when the battery voltage Vdc rises above a predetermined fluctuation rate, while the onboard charger 20 (20a) is charging the battery 14, and the BUS voltage appropriateness determination unit 36 determines that the BUS voltage Vbus is smaller than the command value control threshold Vtha, will reduce the charging current command value Itarget by a predetermined amount ContVala. The detailed operation will be described later (see Figures 5, 6, 7, and 8). As a result, the charging current command unit 37 causes the onboard charger 20 (20a) to maintain charging operation. The charging current command unit 37 also performs charging current control based on the charging current command value Itarget.
[0046] The PFC current command unit 38 reduces the PFC current command value Ipfc (constant current control) by a predetermined amount PFCCont when the battery voltage Vdc falls below a predetermined fluctuation rate while the onboard charger 20 (20a) is charging the battery 14, and the BUS voltage appropriateness determination unit 36 determines that the BUS voltage Vbus is greater than the command value control threshold Vthb. A detailed explanation of the operation will be described later (see Figures 9 and 10). As a result, the PFC current command unit 38 causes the onboard charger 20 (20a) to maintain the charging operation.
[0047] The discharge power command unit 39 lowers the discharge power command value Ptarget by a predetermined amount CcontValb when, for example, the AC current Iac decreases beyond a predetermined fluctuation rate while the onboard charger 20 (20b) is driving the load 16, and the BUS voltage appropriateness determination unit 36 determines that the BUS voltage Vbus is greater than the command value control threshold Vthd. The detailed operation will be described later (see Figures 11 and 12). Also, the discharge power command unit 39 increases the discharge power command value Ptarget by a predetermined amount CcontValb when, for example, the AC current Iac increases beyond a predetermined fluctuation rate while the onboard charger 20 (20b) is driving the load 16, and the BUS voltage appropriateness determination unit 36 determines that the BUS voltage Vbus is less than the command value control threshold Vthc. The detailed operation will be described later (see Figures 13 and 14). As a result, the discharge power command unit 39 causes the onboard charger 20 (20b) to maintain the discharge operation.
[0048] The charge / discharge state determination unit 40 determines whether the onboard charger 20 is charging, whether there is an instruction to end charging, whether the onboard charger 20 is discharging, or whether the power supply to the load 16 has stopped.
[0049] (Process flow of the on-board charger) The processing flow of the on-board charger 20 of the embodiment will be explained using Figure 4. Figure 4 is a flowchart showing an example of the processing flow of the on-board charger according to the embodiment.
[0050] The charge / discharge state determination unit 40 determines whether the onboard charger 20 is charging (step S11). If it is determined that the onboard charger 20 is charging (step S11: Yes), the process proceeds to step S12. On the other hand, if it is determined that the onboard charger 20 is not charging (step S11: No), the process proceeds to step S20.
[0051] In step S11, if it is determined that the onboard charger 20 is charging, the AC voltage measurement unit 31 monitors the voltage across the voltmeter 25 (AC voltage Vac) to determine whether the AC voltage Vac has fallen below a predetermined rate of change (step S12). If it is determined that the AC voltage Vac has fallen below a predetermined rate of change (step S12: Yes), the process proceeds to step S13. On the other hand, if it is not determined that the AC voltage Vac has fallen below a predetermined rate of change (step S12: No), the process proceeds to step S14.
[0052] In step S12, if it is determined that the AC voltage Vac has fallen below a predetermined rate of change, the onboard charger 20 (20a) performs charging current control #1 (step S13). The details of charging current control #1 performed in step S13 will be described later (see Figures 5 and 6). The process then proceeds to step S19.
[0053] On the other hand, if it is not determined in step S12 that the AC voltage Vac has fallen below a predetermined rate of fluctuation, the battery voltage measurement unit 32 monitors the voltage across the voltmeter 28 (battery voltage Vdc) to determine whether the battery voltage Vdc has risen above a predetermined rate of fluctuation (step S14). If it is determined that the battery voltage Vdc has risen above a predetermined rate of fluctuation (step S14: Yes), the process proceeds to step S15. On the other hand, if it is not determined that the battery voltage Vdc has risen above a predetermined rate of fluctuation (step S14: No), the process proceeds to step S16.
[0054] In step S14, if it is determined that the battery voltage Vdc has risen above a predetermined rate of change, the onboard charger 20 (20a) performs charging current control #2 (step S15). The charging current control #2 performed in step S15 will be described in detail later (see Figures 7 and 8). The process then proceeds to step S19.
[0055] On the other hand, if it is not determined in step S14 that the battery voltage Vdc has risen above a predetermined rate of fluctuation, the battery voltage measurement unit 32 monitors the voltage across the voltmeter 28 (battery voltage Vdc) to determine whether the battery voltage Vdc has fallen below a predetermined rate of fluctuation (step S16). If it is determined that the battery voltage Vdc has fallen below a predetermined rate of fluctuation (step S16: Yes), the process proceeds to step S17. On the other hand, if it is not determined that the battery voltage Vdc has fallen below a predetermined rate of fluctuation (step S16: No), the process proceeds to step S18.
[0056] In step S16, if it is determined that the battery voltage Vdc has fallen below a predetermined rate of change, the onboard charger 20 (20a) performs PFC current control (step S17). The PFC current control performed in step S17 will be described in detail later (see Figures 9 and 10). The process then proceeds to step S19.
[0057] On the other hand, if it is determined in step S16 that the battery voltage Vdc has not fallen below a predetermined rate of change, the onboard charger 20 (20a) controls the charging current based on the charging current command value Itarget (see Figure 5) (step S18). The process then proceeds to step S19.
[0058] Following steps S13, S15, S17, and S18, the charge / discharge state determination unit 40 determines whether it has received a charge termination instruction (step S19). If it is determined that a charge termination instruction has been received (step S19: Yes), the onboard charger 20 (20a) terminates its operation. On the other hand, if it is not determined that a charge termination instruction has been received (step S19: No), the process returns to step S12 and the above-described process is repeated.
[0059] Let's return to step S11 of the explanation. In step S11, if it is not determined that the onboard charger 20 is charging, the charge / discharge state determination unit 40 determines whether the onboard charger 20 is supplying power to the load 16 (step S20). If it is determined that the onboard charger 20 is supplying power to the load 16 (step S20: Yes), the process proceeds to step S21. On the other hand, if it is not determined that the onboard charger 20 is supplying power to the load 16 (step S20: No), the onboard charger 20 terminates its processing.
[0060] In step S20, when it is determined that the onboard charger 20 is supplying power to the load 16, the AC current measurement unit 33 determines, for example, whether the AC current Iac has fallen below a predetermined fluctuation rate by monitoring the AC current Iac flowing through the ammeter 24 (step S21). If it is determined that the AC current Iac has fallen below a predetermined fluctuation rate (step S21: Yes), the process proceeds to step S22. On the other hand, if it is not determined that the AC current Iac has fallen below a predetermined fluctuation rate (step S21: No), the process proceeds to step S23.
[0061] In step S21, for example, if it is determined that the AC current Iac has fallen below a predetermined fluctuation rate, the onboard charger 20 (20b) performs discharge power control #1 (step S22). Discharge power control #1 performed in step S22 will be described in detail later (see Figures 11 and 12). The process then proceeds to step S26.
[0062] On the other hand, in step S21, if it is not determined that the AC current Iac has decreased beyond a predetermined fluctuation rate, the AC current measuring unit 33 determines whether the AC current Iac has increased beyond a predetermined fluctuation rate by monitoring the AC current Iac flowing through the ammeter 24, for example (step S23). If it is determined that the AC current Iac has increased beyond a predetermined fluctuation rate (step S23: Yes), the process proceeds to step S24. On the other hand, if it is not determined that the AC current Iac has increased beyond a predetermined fluctuation rate (step S23: No), the process proceeds to step S25.
[0063] In step S23, for example, if it is determined that the AC current Iac has risen above a predetermined fluctuation rate, the onboard charger 20 (20b) performs discharge power control #2 (step S24). Discharge power control #2 performed in step S24 will be described in detail later (see Figures 13 and 14). The process then proceeds to step S26.
[0064] On the other hand, in step S23, if it is determined that the AC current Iac has risen above a predetermined rate of change, for example, the onboard charger 20 (20b) continues discharging with power corresponding to the AC load current (step S25). Then, the process proceeds to step S26.
[0065] Following steps S22, S24, and S25, the charge / discharge state determination unit 40 determines whether the power supply to the load 16 has stopped (step S26). If it is determined that the power supply to the load 16 has stopped (step S26: Yes), the onboard charger 20 (20b) terminates its operation. On the other hand, if it is not determined that the power supply to the load 16 has stopped (step S26: No), the process returns to step S21 and the above-described process is repeated.
[0066] (Operation of charging current control #1) The charging current control #1 performed by the onboard charger 20 (20a) will be explained using Figures 5 and 6. Figure 5 is a diagram showing an example of a timing chart of the operation control performed by the onboard charger according to the embodiment when the AC voltage drops sharply beyond a predetermined fluctuation rate during charging operation. Figure 6 is a flowchart showing an example of the processing flow performed by the onboard charger according to the embodiment when the AC voltage drops sharply beyond a predetermined fluctuation rate during charging operation.
[0067] In the period from time t1 to time t3 shown in Figure 5, if the AC voltage Vac of the AC power supply 12 drops sharply beyond a predetermined fluctuation rate, the onboard charger 20 (20a) increases the AC current Iac to maintain charging power, in other words, to maintain a constant power supply to the DC-DC converter 22 (from time t1 to time t2 in Figure 5). At this time, onboard chargers not to which this disclosure applies generally detect that a current exceeding the overcurrent threshold Ia shown in Figure 5 has flowed and stop charging in order to prevent damage to the hardware of the onboard charger due to the increase in AC current Iac.
[0068] In contrast, the on-board charger 20 (20a) of this embodiment limits the AC current Iac to an AC current limit value Ith that is below the overcurrent threshold Ia (from time t2 to time t4 in Figure 5).
[0069] When the AC current Iac is limited to the AC current limit value Ith, the BUS voltage Vbus decreases (from time t2 to time t3 in Figure 5). If the BUS voltage Vbus continues to decrease in this manner, it will reach the voltage reduction threshold Va, and the onboard charger 20 (20a) will stop charging. Therefore, in this embodiment, when the onboard charger 20 (20a) detects that the BUS voltage Vbus is less than or equal to the command value control threshold Vtha, which is greater than the voltage reduction threshold Va (time t3 in Figure 5), it reduces the charging current command value Itarget to prevent the BUS voltage Vbus from falling below the voltage reduction threshold Va. Note that the command value control threshold Vtha is an example of a first threshold in this disclosure.
[0070] More specifically, if the onboard charger 20 (20a) detects at time t3 in Figure 5 that the BUS voltage Vbus is less than the command value control threshold Vtha which is greater than the voltage reduction threshold Va, it reduces the charging current command value Itarget supplied to the AC-DC converter 21 by a predetermined amount ContVala.
[0071] By reducing the charging current command value Itarget, the charging current Idc decreases by a predetermined amount ContVala from the charging current value Iint (time t3 in Figure 5). This controls the BUS voltage Vbus so that it does not fall below the voltage reduction threshold Va (from time t3 to time t4 in Figure 5). If the BUS voltage Vbus is still below the command value control threshold Vtha even after reducing the charging current command value Itarget by a predetermined amount ContVala, the charging current command value Itarget may be further reduced by a predetermined amount ContVala.
[0072] The onboard charger 20 (20a) performs this control and, when it detects that the BUS voltage Vbus is greater than or equal to the BUS voltage lower limit Vmina and less than or equal to the BUS voltage upper limit Vmaxa, it increases the charging current command value Itarget by a predetermined amount ContVala. This returns the charging current Idc to the charging current value Iint before this control was executed (from time t4 to time t5 in Figure 5). Here, when increasing the charging current command value Itarget by a predetermined amount ContVala, there is a risk that the PFC voltage, which is the output of the power factor correction circuit, may undershoot, so it is desirable to increase it gradually at a predetermined rate of change. The BUS voltage lower limit Vmina and BUS voltage upper limit Vmaxa represent the lower and upper limits of the BUS voltage Vbus output by the AC-DC converter 21 when it is operating normally.
[0073] Furthermore, the charging current control #1 described here is effective not only when the AC voltage Vac of the AC power supply 12 drops sharply, but also when a momentary interruption of the AC power supply 12 occurs due to a power outage or the like.
[0074] Next, we will explain the processing flow of charging current control #1 using the flowchart in Figure 6.
[0075] The AC current measurement unit 33 determines whether the AC current Iac exceeds the AC current limit value Ith (step S31). If it is determined that the AC current Iac exceeds the AC current limit value Ith (step S31: Yes), the process proceeds to step S32. On the other hand, if it is not determined that the AC current Iac exceeds the AC current limit value Ith (step S31: No), the process proceeds to step S37.
[0076] In step S31, if it is determined that the AC current Iac exceeds the AC current limit value Ith, the BUS voltage Vbus decreases. The BUS voltage appropriateness determination unit 36 determines whether the BUS voltage Vbus is smaller than the command value control threshold Vtha (step S32). If it is determined that the BUS voltage Vbus is smaller than the command value control threshold Vtha (step S32: Yes), the process proceeds to step S33. On the other hand, if it is not determined that the BUS voltage Vbus is smaller than the command value control threshold Vtha (step S32: No), the process proceeds to step S37.
[0077] In step S32, if it is determined that the BUS voltage Vbus is smaller than the command value control threshold Vtha, the charging current command unit 37 reduces the charging current command value Itarget by a predetermined amount ContVala (step S33). By executing step S33, the charging current Idc decreases.
[0078] The BUS voltage appropriateness determination unit 36 determines whether the BUS voltage Vbus is equal to or greater than the command value control threshold Vtha (step S34). If it is determined that the BUS voltage Vbus is equal to or greater than the command value control threshold Vtha (step S34: Yes), the process proceeds to step S35. On the other hand, if it is determined that the BUS voltage Vbus is not equal to or greater than the command value control threshold Vtha (step S34: No), the process returns to step S33. Note that the command value control threshold Vtha may have hysteresis.
[0079] In step S34, if it is determined that the BUS voltage Vbus is greater than or equal to the command value control threshold Vtha, the BUS voltage appropriateness determination unit 36 determines whether the BUS voltage Vbus is between the BUS voltage lower limit Vmina and the BUS voltage upper limit Vmaxa (step S35). If it is determined that the BUS voltage Vbus is between the BUS voltage lower limit Vmina and the BUS voltage upper limit Vmaxa (step S35: Yes), the process proceeds to step S36. On the other hand, if it is determined that the BUS voltage Vbus is not between the BUS voltage lower limit Vmina and the BUS voltage upper limit Vmaxa (step S35: No), the determination in step S35 is repeated.
[0080] In step S35, if it is determined that the BUS voltage Vbus is between the BUS voltage lower limit Vmina and the BUS voltage upper limit Vmaxa, the charging current command unit 37 increases the charging current command value Itarget by a predetermined amount ContVala (step S36).
[0081] The charging current command unit 37 controls the charging current based on the charging current command value Itarget before the AC voltage Vac drops below a predetermined fluctuation rate (step S37). After that, it returns to the main routine (Figure 4).
[0082] (Operation of charging current control #2) The charging current control #2 performed by the onboard charger 20 (20a) will be explained using Figures 7 and 8. Figure 7 is a diagram showing an example of a timing chart of the operation control performed by the onboard charger according to the embodiment when the battery voltage rises sharply and exceeds a predetermined fluctuation rate during charging. Figure 8 is a flowchart showing an example of the processing flow performed by the onboard charger according to the embodiment when the battery voltage rises sharply and exceeds a predetermined fluctuation rate during charging.
[0083] If the battery voltage Vdc rises sharply beyond a predetermined fluctuation rate between time t7 and time t8 as shown in Figure 7, the PFC built into the onboard charger 20 (20a) will not be able to keep up, and the BUS voltage Vbus will drop. If the BUS voltage Vbus continues to drop and reaches the undervoltage threshold Va, an onboard charger that does not apply this disclosure will stop charging.
[0084] In contrast, the in-vehicle charger 20 (20a) of this embodiment, when it detects at time t8 in Figure 7 that the BUS voltage Vbus is less than the command value control threshold Vtha which is greater than the voltage reduction threshold Va, reduces the charging current command value Itarget supplied to the AC-DC converter 21 by a predetermined amount ContVala.
[0085] By reducing the charging current command value Itarget, the charging current Idc decreases by a predetermined amount ContVala from the charging current value Iint (time t8 in Figure 7). This controls the BUS voltage Vbus so that it does not fall below the voltage reduction threshold Va (from time t8 to time t9 in Figure 7). If the BUS voltage Vbus is still below the command value control threshold Vtha even after reducing the charging current command value Itarget by a predetermined amount ContVala, the charging current command value Itarget may be further reduced by a predetermined amount ContVala.
[0086] The onboard charger 20 (20a) performs this control and, when it detects that the BUS voltage Vbus is greater than or equal to the BUS voltage lower limit Vmina and less than or equal to the BUS voltage upper limit Vmaxa, it increases the charging current command value Itarget by a predetermined amount ContVala. This returns the charging current Idc to the charging current value Iint before this control was executed (from time t9 to time t10 in Figure 7). Here, when increasing the charging current command value Itarget by a predetermined amount ContVala, there is a risk that the PFC voltage, which is the output of the power factor correction circuit, may undershoot, so it is desirable to increase it gradually at a predetermined rate of change.
[0087] Next, the process flow of charging current control #2 will be explained using the flowchart in Figure 8. In this case, the battery voltage Vdc rises sharply beyond a predetermined fluctuation rate, causing the BUS voltage Vbus to decrease.
[0088] The BUS voltage appropriateness determination unit 36 determines whether the BUS voltage Vbus is smaller than the command value control threshold Vtha (step S41). If it is determined that the BUS voltage Vbus is smaller than the command value control threshold Vtha (step S41: Yes), the process proceeds to step S42. On the other hand, if it is not determined that the BUS voltage Vbus is smaller than the command value control threshold Vtha (step S41: No), the process proceeds to step S46.
[0089] In step S41, if it is determined that the BUS voltage Vbus is smaller than the command value control threshold Vtha, the charging current command unit 37 reduces the charging current command value Itarget by a predetermined amount ContVala (step S42). By executing step S42, the charging current Idc decreases.
[0090] The BUS voltage appropriateness determination unit 36 determines whether the BUS voltage Vbus is equal to or greater than the command value control threshold Vtha (step S43). If it is determined that the BUS voltage Vbus is equal to or greater than the command value control threshold Vtha (step S43: Yes), the process proceeds to step S44. On the other hand, if it is determined that the BUS voltage Vbus is not equal to or greater than the command value control threshold Vtha (step S43: No), the process returns to step S42. Note that the command value control threshold Vtha may have hysteresis.
[0091] In step S43, if it is determined that the BUS voltage Vbus is greater than or equal to the command value control threshold Vtha, the BUS voltage appropriateness determination unit 36 determines whether the BUS voltage Vbus is between the BUS voltage lower limit Vmina and the BUS voltage upper limit Vmaxa (step S44). If it is determined that the BUS voltage Vbus is between the BUS voltage lower limit Vmina and the BUS voltage upper limit Vmaxa (step S44: Yes), the process proceeds to step S45. On the other hand, if it is determined that the BUS voltage Vbus is not between the BUS voltage lower limit Vmina and the BUS voltage upper limit Vmaxa (step S44: No), the determination in step S44 is repeated.
[0092] In step S44, if it is determined that the BUS voltage Vbus is between the BUS voltage lower limit Vmina and the BUS voltage upper limit Vmaxa, the charging current command unit 37 increases the charging current command value Itarget by a predetermined amount ContVala (step S45).
[0093] The charging current command unit 37 controls the charging current based on the charging current command value Itarget before the battery voltage Vdc rises above a predetermined fluctuation rate (step S46). After that, it returns to the main routine (Figure 4).
[0094] (Operation of PFC current control) The PFC current control performed by the on-board charger 20 (20a) will be explained using Figures 9 and 10. Figure 9 is a diagram showing an example of a timing chart of the control performed by the on-board charger according to the embodiment when the battery voltage drops sharply beyond a predetermined fluctuation rate during charging operation. Figure 10 is a flowchart showing an example of the processing flow performed by the on-board charger according to the embodiment when the battery voltage drops sharply beyond a predetermined fluctuation rate during charging operation.
[0095] If the battery voltage Vdc drops sharply beyond a predetermined fluctuation rate between time t12 and time t13 as shown in Figure 9, the PFC built into the onboard charger 20 (20a) will not be able to keep up, and the BUS voltage Vbus will rise. If the BUS voltage Vbus continues to rise and reaches the overvoltage threshold Vb, an onboard charger that does not apply this disclosure will stop charging.
[0096] In contrast, the in-vehicle charger 20 (20a) of this embodiment, when it detects at time t13 in Figure 9 that the BUS voltage Vbus is greater than the command value control threshold Vthb which is smaller than the overvoltage threshold Vb, reduces the PFC current command value Ipfc (constant current control) supplied to the AC-DC converter 21 by a predetermined amount PFCcnt.
[0097] As a result, the BUS voltage Vbus is controlled so that it does not exceed the overvoltage threshold Vb (from time t13 to time t14 in Figure 9). If the BUS voltage Vbus is still greater than the command value control threshold Vthb even after the PFC current command value Ipfc (constant current control) has been reduced by a predetermined amount PFCcnt, the PFC current command value Ipfc (constant current control) may be further reduced by a predetermined amount PFCcnt.
[0098] The onboard charger 20 (20a) performs this control and, when it detects that the BUS voltage Vbus is greater than or equal to the BUS voltage lower limit Vmina and less than or equal to the BUS voltage upper limit Vmaxa, it continues to control the charging current based on the charging current command value Itarget.
[0099] Next, the process flow of PFC current control will be explained using the flowchart in Figure 10. In this case, the battery voltage Vdc drops sharply beyond a predetermined fluctuation rate, causing the BUS voltage Vbus to rise.
[0100] The BUS voltage appropriateness determination unit 36 determines whether the BUS voltage Vbus is greater than the command value control threshold Vthb (step S51). If it is determined that the BUS voltage Vbus is greater than the command value control threshold Vthb (step S51: Yes), the process proceeds to step S52. On the other hand, if it is not determined that the BUS voltage Vbus is greater than the command value control threshold Vthb (step S51: No), the process proceeds to step S52.
[0101] In step S51, if it is determined that the BUS voltage Vbus is greater than the command value control threshold Vthb, the PFC current command unit 38 reduces the PFC current command value Ipfc (constant current control) by a predetermined amount PFCcnt (step S52). By executing step S52, the BUS voltage Vbus decreases.
[0102] The BUS voltage appropriateness determination unit 36 determines whether the BUS voltage Vbus is less than or equal to the command value control threshold Vthb (step S53). If it is determined that the BUS voltage Vbus is less than or equal to the command value control threshold Vthb (step S53: Yes), the process proceeds to step S54. On the other hand, if it is not determined that the BUS voltage Vbus is less than or equal to the command value control threshold Vthb (step S53: No), the process returns to step S52. Note that the command value control threshold Vthb may have hysteresis.
[0103] In step S53, if it is determined that the BUS voltage Vbus is less than or equal to the command value control threshold Vthb, the BUS voltage appropriateness determination unit 36 determines whether the BUS voltage Vbus is between the BUS voltage lower limit Vmina and the BUS voltage upper limit Vmaxa (step S54). If it is determined that the BUS voltage Vbus is between the BUS voltage lower limit Vmina and the BUS voltage upper limit Vmaxa (step S54: Yes), the process proceeds to step S55. On the other hand, if it is determined that the BUS voltage Vbus is not between the BUS voltage lower limit Vmina and the BUS voltage upper limit Vmaxa (step S54: No), the determination in step S54 is repeated.
[0104] In step S54, if it is determined that the BUS voltage Vbus is between the lower limit BUS voltage Vmina and the upper limit BUS voltage Vmaxa, the charging current command unit 37 performs charging current control based on the charging current command value Itarget (step S55). After that, the process returns to the main routine (Figure 4).
[0105] (Operation of discharge power control #1) The discharge power control #1 performed by the onboard charger 20 (20b) will be explained using Figures 11 and 12. Figure 11 is a diagram showing an example of a timing chart of the operation control performed by the onboard charger according to the embodiment when the load current drops sharply beyond a predetermined fluctuation rate during discharge operation. Figure 12 is a flowchart showing an example of the processing flow performed by the onboard charger according to the embodiment when the load current drops sharply beyond a predetermined fluctuation rate during discharge operation.
[0106] If, between time t16 and t17 as shown in Figure 11, the AC current Iac, which is the output load current, drops sharply beyond a predetermined fluctuation rate, the output power of the DC-DC converter 22 built into the on-board charger 20 (20b) cannot be instantaneously reduced, resulting in overpower. As a result, the BUS voltage Vbus rises between time t16 and t17 as shown in Figure 11. If the BUS voltage Vbus continues to rise and reaches the overvoltage threshold Vd, an on-board charger that does not apply this disclosure will stop discharging.
[0107] In contrast, the in-vehicle charger 20(20b) of this embodiment, when it detects at time t17 in Figure 11 that the BUS voltage Vbus is greater than the command value control threshold Vthd which is less than the overvoltage threshold Vd, reduces the discharge power command value Ptarget supplied to the DC-DC converter 22 by a predetermined amount CcоntValb.
[0108] As a result, the BUS power Pbus, which is the output power of the DC-DC converter 22, decreases from Pint before control to Pcónt at time t17 in Figure 11. Then, the BUS voltage Vbus is controlled so that it does not exceed the overvoltage threshold Vd (from time t17 to time t18 in Figure 11). Note that if the BUS voltage Vbus is still greater than the command value control threshold Vthd even after the discharge power command value Ptarget is reduced by a predetermined amount CcóntValb, the discharge power command value Ptarget may be further reduced by a predetermined amount CcóntValb.
[0109] The onboard charger 20 (20b) performs this control and, when it detects that the BUS voltage Vbus is greater than or equal to the BUS voltage lower limit Vminb and less than or equal to the BUS voltage upper limit Vmaxb, it continues discharge control with power corresponding to the AC current Iac, which is the output load current.
[0110] Next, we will explain the processing flow of discharge power control #1 using the flowchart in Figure 12.
[0111] The BUS voltage appropriateness determination unit 36 determines whether the BUS voltage Vbus is greater than the command value control threshold Vthd (step S61). If it is determined that the BUS voltage Vbus is greater than the command value control threshold Vthd (step S61: Yes), the process proceeds to step S62. On the other hand, if it is not determined that the BUS voltage Vbus is greater than the command value control threshold Vthd (step S61: No), the process proceeds to step S66. Note that the determination in step S61 may be made based on the change in the BUS voltage Vbus, rather than the absolute value of the BUS voltage Vbus.
[0112] In step S61, if it is determined that the BUS voltage Vbus is greater than the command value control threshold Vthd, the discharge power command unit 39 reduces the discharge power command value Ptarget by a predetermined amount CcontValb (step S62). By executing step S62, the BUS power Pbus is reduced.
[0113] The BUS voltage appropriateness determination unit 36 determines whether the BUS voltage Vbus is less than or equal to the command value control threshold Vthd (step S63). If it is determined that the BUS voltage Vbus is less than or equal to the command value control threshold Vthd (step S63: Yes), the process proceeds to step S64. On the other hand, if it is not determined that the BUS voltage Vbus is less than or equal to the command value control threshold Vthd (step S63: No), the process returns to step S62. Note that the command value control threshold Vthd may have hysteresis.
[0114] In step S63, if it is determined that the BUS voltage Vbus is less than or equal to the command value control threshold Vthd, the BUS voltage appropriateness determination unit 36 determines whether the BUS voltage Vbus is between the BUS voltage lower limit Vminb and the BUS voltage upper limit Vmaxb (step S64). If it is determined that the BUS voltage Vbus is between the BUS voltage lower limit Vminb and the BUS voltage upper limit Vmaxb (step S64: Yes), the process proceeds to step S65. On the other hand, if it is determined that the BUS voltage Vbus is not between the BUS voltage lower limit Vminb and the BUS voltage upper limit Vmaxb (step S64: No), the determination in step S64 is repeated.
[0115] In step S64, if it is determined that the BUS voltage Vbus is between the lower limit BUS voltage Vminb and the upper limit BUS voltage Vmaxb, the discharge power command unit 39 continues discharging with power corresponding to the AC current Iac (AC load current) (step S65). After that, the process returns to the main routine (Figure 4).
[0116] The explanation returns to step S61. In step S61, if it is determined that the BUS voltage Vbus is not greater than the command value control threshold Vthd, the discharge power command unit 39 performs normal control based on the discharge power command value Ptarget (step S66).
[0117] The discharge power command unit 39 controls the BUS supply power based on the discharge power command value Ptarget (step S67). After that, it returns to the main routine (Figure 4).
[0118] (Operation of discharge power control #2) The discharge power control #2 performed by the onboard charger 20 (20b) will be explained using Figures 13 and 14. Figure 13 is a diagram showing an example of a timing chart of the operation control performed by the onboard charger according to the embodiment when the load current rises sharply and exceeds a predetermined fluctuation rate during discharge operation. Figure 14 is a flowchart showing an example of the processing flow performed by the onboard charger according to the embodiment when the load current rises sharply and exceeds a predetermined fluctuation rate during discharge operation.
[0119] If the AC current Iac, which is the output load current, rises sharply beyond a predetermined fluctuation rate between time t21 and time t22 as shown in Figure 13, the output power of the DC-DC converter 22 built into the onboard charger 20 (20b) cannot be increased instantaneously, resulting in a power shortage. As a result, the BUS voltage Vbus decreases between time t21 and time t22 as shown in Figure 13. If the BUS voltage Vbus continues to decrease and reaches the undervoltage threshold Vc, an onboard charger that does not apply this disclosure will stop discharging.
[0120] In contrast, the in-vehicle charger 20(20b) of this embodiment, when it detects at time t22 in Figure 13 that the BUS voltage Vbus is less than the command value control threshold Vthc which is greater than the voltage reduction threshold Vc, increases the discharge power command value Ptarget supplied to the DC-DC converter 22 by a predetermined amount CcоntValb.
[0121] As a result, the BUS power Pbus, which is the output power of the DC-DC converter 22, increases from Pint before control to Pcоnt at time t22 in Figure 13. Then, the BUS voltage Vbus is controlled so that it does not fall below the voltage reduction threshold Vc (from time t22 to time t23 in Figure 13). Note that if the BUS voltage Vbus is still smaller than the command value control threshold Vthc even after increasing the discharge power command value Ptarget by a predetermined amount CcоntValb, the discharge power command value Ptarget may be further increased by a predetermined amount CcоntValb.
[0122] The onboard charger 20 (20b) performs this control and, when it detects that the BUS voltage Vbus is greater than or equal to the BUS voltage lower limit Vminb and less than or equal to the BUS voltage upper limit Vmaxb, it continues discharge control with power corresponding to the AC current Iac, which is the output load current.
[0123] Next, we will explain the processing flow of discharge power control #2 using the flowchart in Figure 14.
[0124] The BUS voltage appropriateness determination unit 36 determines whether the BUS voltage Vbus is smaller than the command value control threshold Vthc (step S71). If it is determined that the BUS voltage Vbus is smaller than the command value control threshold Vthc (step S71: Yes), the process proceeds to step S72. On the other hand, if it is not determined that the BUS voltage Vbus is smaller than the command value control threshold Vthc (step S71: No), the process proceeds to step S76. Note that the determination in step S71 may be made based on the change in the BUS voltage Vbus, rather than the absolute value of the BUS voltage Vbus.
[0125] In step S71, if it is determined that the BUS voltage Vbus is less than the command value control threshold Vthc, the discharge power command unit 39 increases the discharge power command value Ptarget by a predetermined amount CcontValb (step S72). By executing step S72, the BUS power Pbus increases.
[0126] The BUS voltage appropriateness determination unit 36 determines whether the BUS voltage Vbus is equal to or greater than the command value control threshold Vthc (step S73). If it is determined that the BUS voltage Vbus is equal to or greater than the command value control threshold Vthc (step S73: Yes), the process proceeds to step S74. On the other hand, if it is determined that the BUS voltage Vbus is not equal to or greater than the command value control threshold Vthc (step S73: No), the process returns to step S72. Note that the command value control threshold Vthc may have hysteresis.
[0127] In step S73, if it is determined that the BUS voltage Vbus is greater than or equal to the command value control threshold Vthc, the BUS voltage appropriateness determination unit 36 determines whether the BUS voltage Vbus is between the BUS voltage lower limit Vminb and the BUS voltage upper limit Vmaxb (step S74). If it is determined that the BUS voltage Vbus is between the BUS voltage lower limit Vminb and the BUS voltage upper limit Vmaxb (step S74: Yes), the process proceeds to step S75. On the other hand, if it is determined that the BUS voltage Vbus is not between the BUS voltage lower limit Vminb and the BUS voltage upper limit Vmaxb (step S74: No), the determination in step S74 is repeated.
[0128] In step S74, if it is determined that the BUS voltage Vbus is between the lower limit BUS voltage Vminb and the upper limit BUS voltage Vmaxb, the discharge power command unit 39 continues discharging with power corresponding to the AC current Iac (AC load current) (step S75). After that, the process returns to the main routine (Figure 4).
[0129] The explanation returns to step S71. In step S71, if it is determined that the BUS voltage Vbus is not smaller than the command value control threshold Vthc, the discharge power command unit 39 performs normal control based on the discharge power command value Ptarget (step S76).
[0130] The discharge power command unit 39 controls the BUS supply power based on the discharge power command value Ptarget (step S77). After that, it returns to the main routine (Figure 4).
[0131] (Effects of the embodiment) As described above, the on-board charger 20 (20a, 20b) (power control device) according to the embodiment has input terminals 21a, 21b (first input terminals) and output terminals 21c, 21d (first output terminals), and an AC-DC converter 21 that converts the AC voltage of the AC power supply 12 connected to the input terminals 21a, 21b into a DC voltage and outputs it from the output terminals 21c, 21d, or converts the DC voltage input to the output terminals 21c, 21d into an AC voltage and supplies it to the load 16 connected to the input terminals 21a, 21b in place of the AC power supply 12, and input terminals 22a, 22b A DC-DC converter 22 has a second input terminal and output terminals 22c, 22d (second output terminals), and boosts or decrements the DC voltage from the output terminals 21c, 21d of the AC-DC converter 21 connected to input terminals 22a, 22b to charge the battery 14 connected to output terminals 22c, 22d, or decrements or boosts the DC voltage of the battery 14 and outputs it from input terminals 22a, 22b, and when the battery 14 is in a charging state, the output voltage of the AC power supply 12 or the output voltage of the battery 14 fluctuates, causing the output terminals 21c,When the BUS voltage Vbus of 21d is less than the command value control threshold Vtha (first threshold), which is greater than the undervoltage threshold Va, at which the operation of the onboard charger 20a stops, the DC-DC converter 22 is instructed to adjust the charging current command value Itarget. Alternatively, when the BUS voltage Vbus becomes greater than the command value control threshold Vthb (second threshold), which is less than the overvoltage threshold Vb, at which the operation of the onboard charger 20a stops, the AC-DC converter 21 is instructed to adjust the PFC current command value Ipfc. By doing so, a command is given to the battery 14 to supply power to the load 16, thereby keeping the BUS voltage Vbus within the range between the BUS voltage lower limit Vmina and the BUS voltage upper limit Vmaxa (first predetermined range). When the system is supplying power, if the current flowing through the load 16 fluctuates, causing the BUS voltage Vbus to become less than a command value control threshold Vthc (third threshold) which is greater than the undervoltage threshold Vc at which the operation of the onboard charger 20b is stopped, or greater than a command value control threshold Vthd (fourth threshold) which is greater than the overvoltage threshold Vd at which the operation of the onboard charger 20b is stopped, the system includes a controller 23 (power control unit) that adjusts the discharge power command value Ptarget supplied to the DC-DC converter 22, thereby issuing a command to keep the BUS voltage Vbus between the BUS voltage lower limit Vminb and the BUS voltage upper limit Vmaxb (second predetermined range). Therefore, even if voltage fluctuations or load current fluctuations occur, the system can continue operating without stopping the charging and discharging operation.
[0132] Furthermore, in the on-board charger 20 (20a, 20b) (power control device) according to the embodiment, the controller 23 (power control unit) issues a command to keep the BUS voltage Vbus between the BUS voltage lower limit Vmina and the BUS voltage upper limit Vmaxa (first predetermined range), and when the BUS voltage Vbus falls between the BUS voltage lower limit Vmina and the BUS voltage upper limit Vmaxa, it returns the charging current command value Itarget or the PFC current command value Ipfc to its state before control, or, after issuing a command to keep the BUS voltage Vbus between the BUS voltage lower limit Vminb and the BUS voltage upper limit Vmaxb (second predetermined range), when the BUS voltage Vbus falls between the BUS voltage lower limit Vminb and the BUS voltage upper limit Vmaxb, it returns the discharge power command value Ptarget to a value corresponding to the load current.Therefore, operation can be continued without stopping the charging and discharging operation.
[0133] Furthermore, in the on-board charger 20 (20a) according to the embodiment, when the battery 14 is in a charging state, if the AC voltage Vac, which is the output voltage of the AC power supply 12, drops below a predetermined fluctuation rate, the controller 23 (power control unit) issues a command to the DC-DC converter 22 to reduce the charging current command value Itarget by a predetermined amount ContVala, provided that the BUS voltage Vbus becomes smaller than the command value control threshold Vtha (first threshold). Therefore, even if the AC voltage Vac drops sharply while the battery 14 is charging, the operation can be continued without stopping the charging operation.
[0134] Furthermore, in the on-board charger 20 (20a) according to the embodiment, when the battery 14 is in a charging state, if the battery voltage Vdc rises above a predetermined fluctuation rate, the controller 23 (power control unit) issues a command to the DC-DC converter 22 to reduce the charging current command value Itarget by a predetermined amount ContVala, provided that the BUS voltage Vbus becomes smaller than the command value control threshold Vtha (first threshold). Therefore, even if the battery voltage Vdc rises sharply while the battery 14 is charging, the operation can be continued without stopping the charging operation.
[0135] Furthermore, in the on-board charger 20 (20a) according to the embodiment, when the battery 14 is in a charging state, if the battery voltage Vdc falls below a predetermined fluctuation rate, the controller 23 (power control unit) issues a command to the AC-DC converter 21 to reduce the PFC current command value Ipfc by a predetermined amount PFCCont, provided that the BUS voltage Vbus becomes greater than the command value control threshold Vthb (second threshold). Therefore, even if the battery voltage Vdc drops sharply while the battery 14 is charging, the operation can be continued without stopping the charging operation.
[0136] Furthermore, in the on-board charger 20(20b) according to the embodiment, when the battery 14 is in a state of driving the load 16, if the AC current Iac (AC load current) drops below a predetermined fluctuation rate, the controller 23 (power control unit) issues a command to the DC-DC converter 22 to reduce the discharge power command value Ptarget by a predetermined amount CcontValb, provided that the BUS voltage Vbus becomes greater than the command value control threshold Vthd (fourth threshold). Therefore, even if the AC current Iac (AC load current) drops sharply while the battery 14 is driving the load 16, the operation can be continued without stopping the discharge operation.
[0137] Furthermore, in the on-board charger 20(20b) according to the embodiment, when the battery is in a state of driving the load, if the AC current Iac (AC load current) rises above a predetermined fluctuation rate, the controller 23 (power control unit) issues a command to the DC-DC converter to increase the power command value by a predetermined amount, provided that the BUS voltage Vbus becomes smaller than the command value control threshold Vthc (third threshold). Therefore, even if the AC current Iac (AC load current) rises sharply while the battery 14 is driving the load 16, the operation can be continued without stopping the discharge operation.
[0138] Although embodiments of the present invention have been described above, these embodiments are presented as examples only and are not intended to limit the scope of the invention. This novel embodiment can be implemented in various other forms. Furthermore, various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. Moreover, this embodiment is included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of symbols]
[0139] 12…AC power supply, 14…Battery, 16…Load, 20,20a,20b…On-board charger (power control device), 20p,20q…Input terminal (output terminal), 20r,20s…Output terminal (input terminal), 21…AC-DC converter, 21a,21b…Input terminal (first input terminal), 21c,21d…Output terminal (first output terminal), 22…DC-DC converter, 22a,22b…Input terminal (second input terminal), 22c,22d…Output terminal (second output terminal), 23…Controller (power control unit), 24,27…Ammeter, 25,26,28…Voltmeter, 31…AC voltage measurement unit, 32…Battery voltage measurement unit, 33…AC current measurement unit, 34…Charging current measurement unit, 35…B 36...BUS voltage measurement unit, 37...BUS voltage appropriateness determination unit, 38...Charging current command unit, 39...PFC current command unit, 40...Discharge power command unit, 40...Charge / discharge state determination unit, Vac...AC voltage, Iac...AC current, Ia...Overcurrent threshold, Ith...AC current limit, Vbus...BUS voltage, Vdc...Battery voltage, Idc...Charging current, Itarget...Charging current command value, Ipfc...PFC current command value, Ptarget...Discharge power command value, Vmina, Vminb...BUS voltage lower limit, Vmaxa, Vmaxb...BUS voltage upper limit, Va, Vc...Undervoltage threshold, Vb, Vd...Overvoltage threshold, Vtha...Command value control threshold (first threshold), Vthb...Command value control threshold (second threshold)
Claims
1. An AC-DC converter having a first input terminal and a first output terminal, which converts the AC voltage of an AC power supply connected to the first input terminal into a DC voltage and outputs it from the first output terminal, or converts the DC voltage input to the first output terminal into an AC voltage and supplies it to a load connected to the first input terminal in place of the AC power supply, A DC-DC converter having a second input terminal and a second output terminal, which boosts or decrements the DC voltage from the first output terminal of the AC-DC converter connected to the second input terminal to charge a battery connected to the second output terminal, or decrements or boosts the DC voltage of the battery and outputs it from the second input terminal, The power control unit comprises: When the battery is in a charging state, if the output voltage of the AC power supply or the output voltage of the battery fluctuates and the BUS voltage, which is the voltage at the first output terminal, becomes less than a first threshold greater than a devoltage threshold greater than the devoltage threshold at which the operation of the power control unit is stopped, or greater than a second threshold greater than an overvoltage threshold greater than the overvoltage threshold at which the operation of the power control unit is stopped, the power control unit commands the DC-DC converter to adjust the charging current command value or the PFC current command value to the AC-DC converter to keep the BUS voltage within a first predetermined range; When the battery is supplying power to the load, if the current flowing through the load fluctuates and the BUS voltage becomes less than a third threshold greater than the devoltage threshold at which the operation of the power control unit is stopped, or greater than a fourth threshold greater than an overvoltage threshold greater than the overvoltage threshold at which the operation of the power control unit is stopped, the power control unit commands the DC-DC converter to adjust the discharge power command value to be supplied to the DC-DC converter to keep the BUS voltage within a second predetermined range. Power control device.
2. The power control unit, After issuing a command to bring the BUS voltage within the first predetermined range, if the BUS voltage is within the first predetermined range, the charging current command value or the PFC current command value may be returned to its state before control. Alternatively, after issuing a command to keep the BUS voltage within the second predetermined range, if the BUS voltage is within the second predetermined range, the discharge power command value is returned to a value corresponding to the load current. The power control device according to claim 1.
3. The power control unit, When the aforementioned battery is in a charging state, When the output voltage of the AC power supply falls below a predetermined fluctuation rate, and the BUS voltage falls below the first threshold, a command is given to the DC-DC converter to reduce the charging current command value by a predetermined amount. The power control device according to claim 1 or claim 2.
4. The power control unit, When the aforementioned battery is in a charging state, When the voltage of the battery rises above a predetermined fluctuation rate, and the BUS voltage falls below the first threshold, a command is given to the DC-DC converter to reduce the charging current command value by a predetermined amount. The power control device according to claim 1 or claim 2.
5. The power control unit, When the aforementioned battery is in a charging state, When the voltage of the battery falls below a predetermined fluctuation rate, and the BUS voltage becomes greater than the second threshold, a command is given to the AC-DC converter to reduce the PFC current command value by a predetermined amount. The power control device according to claim 1 or claim 2.
6. The power control unit, When the battery is in a state that is driving the load, When the AC load current falls below a predetermined fluctuation rate, and the BUS voltage becomes greater than the fourth threshold, a command is given to the DC-DC converter to reduce the discharge power command value by a predetermined amount. The power control device according to claim 1 or claim 2.
7. The power control unit, When the battery is in a state that is driving the load, When the AC load current rises above a predetermined rate of fluctuation, and the BUS voltage falls below the third threshold, a command is given to the DC-DC converter to increase the discharge power command value by a predetermined amount. The power control device according to claim 1 or claim 2.