Charging device

Abstract

To provide a technique capable of executing constant current charging and constant voltage charging with a simple configuration.SOLUTION: A charging device may be capable of performing constant current charging in which a secondary battery is charged in a state where variations in charging current are maintained within a predetermined range, and constant voltage charging in which the secondary battery is charged in a state where variations in charging voltage are maintained within the predetermined range. The charging device may include a control unit that controls the charging current in the constant current charging and the charging voltage in the constant voltage charging. The control unit may include a compensation unit common to the constant current charging and the constant voltage charging, the compensation unit being capable of executing processing for calculating an operation amount for performing feedback control of the charging current in the constant current charging and processing for calculating an operation amount for performing feedback control of the charging voltage in the constant voltage charging.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The technology disclosed in this specification relates to a charging device. [Background technology]

[0002] Patent Document 1 discloses a power supply circuit including a constant voltage power supply unit that outputs a constant voltage output, and a constant current power supply unit that outputs a constant current output. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2-219426 Summary of the Invention [Problem to be solved by the invention]

[0004] In the configuration of Patent Document 1, the constant voltage power supply unit and the constant current power supply unit are separate, making the configuration complicated. This specification provides a technique that can perform constant current charging and constant voltage charging with a simple configuration. [Means for solving the problem]

[0005] In a first aspect of the present technology, a charging device for charging a secondary battery may be capable of performing constant current charging for charging the secondary battery while maintaining a variation in charging current within a predetermined range, and constant voltage charging for charging the secondary battery while maintaining a variation in charging voltage within a predetermined range. The charging device may include a control unit that controls a charging current in the constant current charging and a charging voltage in the constant voltage charging. The control unit may be a compensation unit common to the constant current charging and the constant voltage charging, and may include the compensation unit that is capable of performing a process for calculating an operation amount for feedback control of the charging current in the constant current charging, and a process for calculating an operation amount for feedback control of the charging voltage in the constant voltage charging.

[0006] According to this configuration, the compensation unit used in common for constant current charging and constant voltage charging can perform calculations to execute feedback control of the charging current and feedback control of the charging voltage, making it possible to execute constant current charging and constant voltage charging with a simple configuration.

[0007] In a second aspect, in the first aspect, the control unit may be capable of multiplying a change in charging current by a current gain in feedback control in the constant current charging, and multiplying a change in charging voltage by a voltage gain in feedback control in the constant voltage charging. The voltage gain may be equal to the current gain / (resistance value of a load to which a charging voltage is applied).

[0008] According to this configuration, the values ​​input to the compensation unit in the feedback control of the charging current and the feedback control of the charging voltage can be made equal, so that a common compensation unit can be used for both constant current charging and constant voltage charging. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating a charging device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a circuit diagram of a converter included in the charging device of the embodiment. [Diagram 3] FIG. 2 is a block diagram of a feedback control in the charging device according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A charging device of the embodiment will be described with reference to the drawings. As shown in Fig. 1, a charging device 2 of the embodiment is connected to an external power source 4 and a secondary battery 6. The charging device 2 is a device that charges the secondary battery 6 with power from the external power source 4. The charging device 2 is a device that converts the output voltage of the external power source 4 (for example, by stepping down or stepping up) and supplies it to the secondary battery 6.

[0011] The external power source 4 is, for example, a commercial power source, a battery, etc. The secondary battery 6 is, for example, a lithium ion battery, a nickel-hydrogen battery, etc. The types of the external power source 4 and the secondary battery 6 are not particularly limited.

[0012] The charging device 2 can perform constant current charging and constant voltage charging when charging the secondary battery 6. Constant current charging is a method of charging the secondary battery 6 while maintaining fluctuations in the charging current supplied to the secondary battery 6 within a predetermined range. Constant current charging is a method of charging the secondary battery 6 while allowing fluctuations in the charging voltage supplied to the secondary battery 6.

[0013] In contrast, constant voltage charging is a method of charging the secondary battery 6 in a state where fluctuations in the charging voltage supplied to the secondary battery 6 are maintained within a predetermined range. Constant voltage charging is a method of charging the secondary battery 6 in a state where fluctuations in the charging current supplied to the secondary battery 6 are tolerated.

[0014] The charging device 2 includes a converter 10 that converts an input voltage from an external power source 4 into an output voltage to the secondary battery 6. The charging device 2 also includes a control unit 100 that controls the operation of the converter 10.

[0015] The converter 10 of the embodiment is an LLC converter having a resonance inductance and a capacitor. As shown in Fig. 2, the converter 10 includes a primary side circuit 52, a secondary side circuit 54, and a transformer 40 arranged between the primary side circuit 52 and the secondary side circuit 54. The converter 10 of the embodiment is an isolated converter in which the primary side circuit 52 and the secondary side circuit 54 are insulated from each other. The type of the converter 10 is not particularly limited.

[0016] A primary side circuit 52 of the converter 10 is connected to an external power supply 4. The output voltage of the external power supply 4 is input to the primary side circuit 52. The primary side circuit 52 includes a first switching element 12, a second switching element 14, a leakage inductance 20, an exciting inductance 22, a primary side capacitor 16, and a primary side coil 42.

[0017] The first switching element 12 and the second switching element 14 are transistors such as, for example, a metal oxide semiconductor field effect transistor (MOSFET) or an insulated gate bipolar transistor (IGBT). The converter 10 converts an input voltage from the external power source 4 into an output voltage to the secondary battery 6 by periodically switching the first switching element 12 and the second switching element 14 on and off alternately.

[0018] The leakage inductance 20 and the primary capacitor 16 of the primary circuit 52 are connected in series with the primary coil 42. The excitation inductance 22 is connected in parallel with the primary coil 42. The primary coil 42 and the secondary coil 44 together form a transformer 40. In the converter 10, the power of the primary circuit 52 is transmitted to the secondary circuit 54 via the transformer 40.

[0019] The secondary side circuit 54 of the converter 10 is connected to a secondary battery 6. The secondary battery 6 includes, for example, a positive electrode 62a and a negative electrode 62b. The secondary battery 6 may also include a load 50. Note that the load 50 may be a load of a device (e.g., a motor, etc.) different from the secondary battery 6.

[0020] The secondary circuit 54 of the converter 10 includes a secondary coil 44, a plurality of rectifier diodes 24a-24d, and a secondary capacitor 18.

[0021] The secondary coil 44 and the primary coil 42 constitute a transformer 40. A current is generated in the secondary circuit 54 by power transmitted to the secondary circuit 54 via the transformer 40. A plurality of rectifier diodes 24a-24d rectify the current in the secondary circuit 54. The secondary capacitor 18 is connected in series with the secondary coil 44.

[0022] In the above converter 10, the output voltage of the secondary side circuit 54 is input to the secondary battery 6. This charges the secondary battery 6. Note that the configuration of an LLC converter is already known, so further detailed description will be omitted.

[0023] The control unit 100 (see FIG. 1) of the charging device 2 includes, for example, a CPU, a ROM, and a RAM, and executes predetermined control and processing related to the charging device 2 according to a predetermined program. As shown in FIG. 3, the control unit 100 includes a compensation unit 102, a gain processing unit 104, a current gain processing unit 110, and a voltage gain processing unit 112. In order to conveniently represent the operation of the circuit, a current behavior unit 106 and a voltage behavior unit 108 are also shown in FIG. 3. The control unit 100 feedback-controls the charging current in constant current charging of the charging device 2. In addition, the control unit 100 feedback-controls the charging voltage in constant voltage charging of the charging device 2.

[0024] The compensation section 102 and the gain processing section 104 of the control section 100 are used in both constant current charging and constant voltage charging. The control section 100 includes the compensation section 102 and the gain processing section 104 that are common to both constant current charging and constant voltage charging.

[0025] The compensation unit 102 and the gain processing unit 104 adjust the frequency manipulation amount (Δf s In this embodiment, for the sake of convenience, the command value is set to "1" in both constant current charging and constant voltage charging.

[0026] In the case of constant current charging, the compensation unit 102 and the gain processing unit 104 calculate the frequency manipulation amount (Δfs) of the first switching element 12 and the second switching element 14 based on the difference between the command value (1) and the output value (output value of the current gain processing unit 110) in the constant current charging. iof (s)×I0gain) and a given transfer function (Gc (s)), the input value (ΔV c The gain processor 104 calculates the output value (ΔV c ) and a predetermined gain (Fm), the frequency control amount (Δf s The predetermined gain (Fm) in the gain processing unit 104 may be calculated by calculation, or may be a predetermined value, for example.

[0027] The control unit 100 of the charging device 2 controls the frequency manipulation amount (Δf s The first switching element 12 and the second switching element 14 are turned on / off according to the frequency after adding ΔI o ) can be calculated by the current behavior unit 106. The charging device 2 calculates the amount of change in the charging current (ΔI o The secondary battery 6 can be charged with the charging current after adding the change in the charging current (ΔI o ) is maintained within a predetermined range.

[0028] In addition, in the case of constant voltage charging, the compensation unit 102 and the gain processing unit 104 calculate the frequency manipulation amount (Δf s Among these, the compensation unit 102 calculates the output value (G vf (s) × V0gain) and a given transfer function (G c (s)), the input value (ΔV c The gain processor 104 calculates the output value (ΔV c ) and a predetermined gain (Fm), the frequency control amount (Δf sThe predetermined gain (Fm) in the gain processing unit 104 may be calculated by calculation, or may be a predetermined value, for example.

[0029] The control unit 100 of the charging device 2 controls the frequency manipulation amount (Δf s The first switching element 12 and the second switching element 14 are turned on / off according to the frequency after adding ΔV. This changes the charging voltage to the secondary battery 6 during constant voltage charging. The amount of change in charging voltage during constant voltage charging (ΔV o ) can be calculated by the voltage behavior unit 108. The charging device 2 calculates the amount of change in the charging voltage (ΔV o The secondary battery 6 can be charged with the charging voltage after adding the charge voltage (ΔV o ) is maintained within a predetermined range.

[0030] As described above, the control unit 100 of the charging device 2 controls the frequency manipulation amount (Δf s The first switching element 12 and the second switching element 14 are controlled by the frequency obtained by adding

[0031] The feedback control will now be described. The current behavior section 106 of the control section 100 is used in constant current charging. In the case of constant current charging, the current behavior section 106 calculates the output value (Δf s ) and a given transfer function (G iof (s)).

[0032] The current gain processing unit 110 is used in constant current charging. In the case of constant current charging, the current gain processing unit 110 calculates the output value (ΔI o ) and a given current gain (I0gain), the sensor value (G iofThe predetermined current gain (I0gain) in the current gain processing unit 110 may be calculated by calculation, or may be a predetermined value.

[0033] As described above, in the case of constant current charging, the compensation unit 102 and the gain processing unit 104 of the control unit 100 calculate the command value (1) and the output value (G iof (s)×I0gain) is used to determine the frequency manipulation amount (Δf s ) is calculated. The control unit 100 repeats the above process to repeatedly execute feedback control of the charging current in constant current charging.

[0034] On the other hand, the voltage behavior unit 108 of the control unit 100 is used in constant voltage charging. In the case of constant voltage charging, the voltage behavior unit 108 calculates the output value (Δf s ) and a given transfer function (G vf (s)).

[0035] The voltage gain processing unit 112 is used in constant voltage charging. In the case of constant voltage charging, the voltage gain processing unit 112 calculates the output value (ΔV o ) and a given voltage gain (V0gain), the sensor value (G vf The voltage gain (V0gain) in the voltage gain processing unit 112 may be calculated by calculation or may be a predetermined value. The voltage gain (V0gain) in the voltage gain processing unit 112 is calculated by multiplying the current gain (I0gain) in the current gain processing unit 110 by 1 / R. L (i.e., V0gain=I0gain / R L ). Here, R L is the resistance value of the load 50 (see FIG. 2) to which the charging voltage is applied (in other words, the resistance value of the load 50 through which the charging current flows).

[0036] As described above, in the case of constant voltage charging, the compensation unit 102 and the gain processing unit 104 of the control unit 100 calculate the command value (1) and the output value (G vf (s)×V0gain) is used to determine the frequency manipulation amount (Δf s ) is calculated. The control unit 100 repeats the above process to repeatedly execute feedback control of the charging voltage in constant voltage charging.

[0037] For each of the above feedback controls, the loop transfer function of the feedback control in constant current charging (C cc (s)) is expressed by the following formula 1. In addition, the loop transfer function of the feedback control in constant voltage charging (C cv (s)) is expressed by the following equation 2.

[0038]

number

[0039]

number

[0040] As shown in the above Equation 1 and Equation 2, the loop transfer function of feedback control in constant current charging (C cc (s)) and the loop transfer function of feedback control in constant voltage charging (C cv (s)) is equal to the current gain (I0gain) and voltage gain (V0gain), V0gain = I0gain / R L As a result, the loop transfer functions in constant current charging and constant voltage charging are equal. Therefore, it is possible to use the same compensation unit 102 and gain processing unit 104 in both constant current charging and constant voltage charging. The values ​​in the above formulas 1 and 2 are as follows:

[0041] n is the number of turns of the primary coil 42 of the converter 10 pand the number of turns n of the secondary coil 44 s Ratio to (n p / n s ) is. C o is the capacitance of the secondary capacitor 18. eq is π 2 / 4×L r is, L r is the inductance of the leakage inductance 20. K f is -2V in L r / πnL m f r and V in is the output voltage of the external power source 4 (the input voltage to the converter 10 of the charging device 2). m is the inductance of the magnetizing inductance 22. r is the resonant frequency of the leakage inductance 20 and the primary capacitor 16. L is the resistance of the load 50, s is the Laplace operator, ω0 is the angular velocity, and K is the gain.

[0042] (effect) The charging device 2 of the embodiment has been described above. As described above, the charging device 2 of the embodiment is capable of constant current charging, which charges the secondary battery 6 while maintaining the fluctuation of the charging current within a predetermined range, and constant voltage charging, which charges the secondary battery 6 while maintaining the fluctuation of the charging voltage within a predetermined range. The control unit 100 of the charging device 2 is a compensation unit 102 common to constant current charging and constant voltage charging, and controls a manipulated variable (Δf s ) and the control variable (Δf s ) and a compensation unit 102 capable of executing the process of calculating the .times. ...

[0043] According to this configuration, the compensation unit 102, which is used in common for constant current charging and constant voltage charging, can perform calculations to execute feedback control of the charging current and feedback control of the charging voltage, so that constant current charging and constant voltage charging can be executed with a simple configuration.

[0044] In addition, the control unit 100 calculates the amount of change in the charging current (ΔI o ) by the current gain (I0gain), and the change in charging voltage (ΔV o ) by a voltage gain (V0gain). In this case, voltage gain = current gain / (resistance value of load 50 to which charging voltage is applied). With this configuration, the sensor values ​​input to compensation unit 102 can be made equal in feedback control of charging current and feedback control of charging voltage. This makes it possible to use a common compensation unit 102 in constant current charging and constant voltage charging.

[0045] Although specific examples of the present invention have been described above in detail, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. The technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of these objectives is itself technically useful. [Explanation of symbols]

[0046] 2: charging device, 4: external power supply, 6: secondary battery, 10: converter, 12: first switching element, 14: second switching element, 16: primary side capacitor, 18: secondary side capacitor, 20: inductance, 22: excitation inductance, 24a-24d: rectifier diodes, 40: transformer, 42: primary side coil, 44: secondary side coil, 50: load, 52: primary side circuit, 54: secondary side circuit, 100: control unit, 102: compensation unit, 104: gain processing unit, 106: current behavior unit, 108: voltage behavior unit, 110: current gain processing unit, 112: voltage gain processing unit

Claims

1. A charging device for charging a secondary battery, a constant current charging step of charging the secondary battery while maintaining a fluctuation in the charging current within a predetermined range; and (b) a constant voltage charging step for charging the secondary battery while maintaining a fluctuation in charging voltage within a predetermined range. a control unit that controls a charging current in the constant current charging and a charging voltage in the constant voltage charging, The control unit is a compensation unit common to the constant current charging and the constant voltage charging, and is capable of executing a process for calculating an operation amount for feedback control of the charging current in the constant current charging, and a process for calculating an operation amount for feedback control of the charging voltage in the constant voltage charging.

2. The charging device according to claim 1, the control unit is capable of executing a process of multiplying a change amount of a charging current by a current gain in a feedback control in the constant current charging, and a process of multiplying a change amount of a charging voltage by a voltage gain in a feedback control in the constant voltage charging, A charging device, wherein the voltage gain=the current gain / (resistance value of a load to which a charging voltage is applied).

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