Controller of charging circuit

Abstract

To perform gain correction of a current sensor used by a current feedback control.SOLUTION: According to a controller of a charging circuit for feeding power fed from a charging stand 3 to a battery 11 via a step-up / step-down, charging is started at an operation point where a current ripple becomes 0, when the charging is started from the charging stand 3 to the battery 11; a current feedback control is executed using sensor values of current sensors 18u, 18v, and 18w that detect currents; and gains of the current sensors 18u, 18v, and 18w are corrected according to the current ripple detected during charging.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a control device for a charging circuit. [Background technology]

[0002] Patent Document 1 discloses a vehicle that charges an on-board battery with power supplied from a charging station. In the configuration described in Patent Document 1, a voltage value at which current ripple is suppressed is transmitted from the vehicle to the charging station, and the charging station controls the input voltage to the received voltage value and supplies power to the vehicle. In the configuration described in Patent Document 1, the number of driving phases and the target voltage are set so that the current ripple is reduced. For example, in the case of two-phase interleaving, the duty is set to 1 / 2, and in the case of three-phase interleaving, the duty is set to 1 / 3 or 2 / 3. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-93608 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when a current sensor with a large gain error is used to perform current feedback control according to the gain error, the current value that includes the error is used in the control, which may result in a decrease in the accuracy of estimating the element load based on the battery value, a decrease in control tracking ability, and an increase in current ripple on the battery side or charging station side.

[0005] For example, when current feedback control is performed using a current sensor that recognizes a gain error that is smaller than the actual current value, the sensor value containing the error is used in the control, causing a deviation from the actual current and resulting in a larger current flowing.

[0006] The present invention has been made in consideration of the above circumstances, and has an object to provide a control device for a charging circuit that is capable of correcting the gain of a current sensor used in current feedback control. [Means for solving the problem]

[0007] The present invention is a control device for a charging circuit that boosts and lowers the power supplied from an external power source and supplies it to an on-board battery, and is characterized in that when charging of the on-board battery from the external power source is started, charging is started at an operating point where the current ripple is zero, and during the charging, current feedback control is performed using a sensor value of a current sensor that detects the current, and the gain of the current sensor is corrected according to the current ripple detected during the charging. Effect of the Invention

[0008] In the present invention, the gain of a current sensor used in current feedback control can be corrected. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating a charging system according to an embodiment. [Diagram 2] FIG. 2 is a flow chart showing a charging control flow. [Diagram 3] FIG. 3 is a flow chart showing a step-up / step-down control flow. [Figure 4] FIG. 4 is a diagram showing the relationship between interleaving, duty, and output current ripple. [Diagram 5] FIG. 5 is a diagram for explaining the requested current value transmitted to the charging facility side. [Figure 6] FIG. 6 is a diagram for explaining the sampling period of the current value. [Figure 7] FIG. 7 is a diagram for explaining the three-phase interleaving. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a charging circuit control device according to an embodiment of the present invention will be described in detail, however, the present invention is not limited to the embodiment described below.

[0011] 1 is a diagram illustrating a charging system according to an embodiment. The charging system 1 includes a vehicle 2 and a charging stand 3. In the charging system 1, power can be supplied from the charging stand 3 to the vehicle 2 to charge an on-board battery of the vehicle 2.

[0012] The vehicle 2 includes a battery 11, a PCU 12, a motor generator 13, and a control device 14. The vehicle 2 also includes a communication device that communicates with the charging station 3.

[0013] The battery 11 is a DC power source capable of being charged and discharged, and is constituted by, for example, a secondary battery such as a nickel-metal hydride or lithium ion battery. The battery 11 discharges power to the PCU 12 side, or charges with power supplied from the PCU 12 side. The battery 11 is an in-vehicle battery mounted on the vehicle 2. The battery 11 stores power supplied from the charging stand 3. The battery 11 is electrically connected to an inlet via the PCU 12 and the motor generator 13.

[0014] The PCU 12 is a power conversion device that converts DC power from the battery 11 into AC power and supplies it to the motor generator 13. The PCU 12 drives the motor generator 13. The PCU 12 is configured with an electric circuit having a plurality of switching elements so that a three-phase current can be applied to the three-phase coils of the motor generator 13. The PCU 12 has first to sixth switching elements SW1 to SW6. A diode is connected in inverse parallel to each of the switching elements SW1 to SW6.

[0015] The first switching element SW1 and the second switching element SW2 are connected in series to form a U-phase arm. In the U-phase arm, the first switching element SW1 is the upper arm, and the second switching element SW2 is the lower arm. The third switching element SW3 and the fourth switching element SW4 are connected in series to form a V-phase arm. In the V-phase arm, the third switching element SW3 is the upper arm, and the fourth switching element SW4 is the lower arm. The fifth switching element SW5 and the sixth switching element SW6 are connected in series to form a W-phase arm. In the W-phase arm, the fifth switching element SW5 is the upper arm, and the sixth switching element SW6 is the lower arm. The U-phase arm consisting of the first switching element SW1 and the second switching element SW2, the V-phase arm consisting of the third switching element SW3 and the fourth switching element SW4, and the W-phase arm consisting of the fifth switching element SW5 and the sixth switching element SW6 are connected in parallel. In the PCU 12, each of the three-phase coils of the motor generator 13 is connected to each of the connection points between the paired switching elements. Each of the switching elements SW1 to SW6 of the PCU 12 is composed of an IGBT, a MOSFET, or the like, and performs a switching operation in response to a control signal from the control device .

[0016] Furthermore, the PCU 12 boosts the power supplied from the charging stand 3 in response to a control signal from the control device 14, and supplies the boosted power to the battery 11. The PCU 12 is provided between an inlet provided in the vehicle 2 and the battery 11.

[0017] The motor generator 13 is a three-phase AC motor generator. The motor generator 13 functions as a power source for traveling, and is a motor generator having the functions of an electric motor and a generator. The vehicle 2 on which the motor generator 13 is mounted is an electric vehicle such as an electric car or a hybrid car. In the vehicle 2, the wheels are driven by the power output from the motor generator 13. The motor generator 13 is a synchronous motor including a rotor in which a permanent magnet is embedded and a stator around which a three-phase coil is wound. The three-phase coils (U phase, V phase, W phase) wound around the stator of the motor generator 13 are electrically connected to the PCU 12. When a three-phase voltage is applied to the motor generator 13 by the PCU 12, a three-phase current flows through the coil of the motor generator 13, and a torque is generated in the motor generator 13.

[0018] The control device 14 is an electronic control device that controls the PCU 12. The control device 14 includes a processor and a memory. The control device 14 loads a program stored in a storage unit into a working area of ​​the memory (main storage device) and executes the program, and realizes a function that meets a predetermined purpose by controlling each component through the execution of the program. Signals from various sensors are input to the control device 14. A signal from the first voltage sensor 16, a signal from the second voltage sensor 17, a signal from the current sensor 18u, a signal from the current sensor 18v, a signal from the current sensor 18w, and a signal from the current sensor 19 are input to the control device 14. Then, the control device 14 executes various controls based on the signals input from the various sensors.

[0019] Capacitor 15 is connected to a parallel line connecting between positive line PL and negative line NL on the lower voltage side than motor generator 13. A neutral point of a coil of motor generator 13 is connected to positive line PL.

[0020] First voltage sensor 16 is a VL sensor that measures the voltage on the low-voltage side of PCU 12. First voltage sensor 16 detects the voltage between power line PL and negative electrode line NL on the lower voltage side than motor generator 13. First voltage sensor 16 is disposed on the inlet side of PCU 12. During external charging, first voltage sensor 16 detects the input voltage of PCU 12, and outputs the input voltage value to control device 14.

[0021] Second voltage sensor 17 is a VH sensor that measures the voltage on the high voltage side of PCU 12. Second voltage sensor 17 detects the voltage between power line PL and negative line NL on the high voltage side of PCU 12. Second voltage sensor 17 is disposed on the battery 11 side of PCU 12. During external charging, second voltage sensor 17 detects the output voltage of PCU 12, and outputs the output voltage value to control device 14.

[0022] The current sensors 18u, 18v, and 18w measure the three-phase currents, respectively.

[0023] The current sensor 18u is provided between the PCU 12 and the motor generator 13 to detect a U-phase current. The current sensor 18u is provided on a wiring that connects a connection point between the first switching element SW1 and the second switching element SW2 of the PCU 12 and one end of the U-phase coil of the motor generator 13. The current sensor 18u detects the U-phase current flowing between the PCU 12 and the motor generator 13, and outputs the U-phase current value, which is the sensor value, to the control device 14. The control device 14 can monitor the sensor value of the current sensor 18u based on a signal input from the current sensor 18u.

[0024] Current sensor 18v ​​is provided between PCU 12 and motor generator 13 to detect a V-phase current. Current sensor 18v ​​is provided on a wire connecting a connection point between the third switching element SW3 and the fourth switching element SW4 of PCU 12 and one end of a V-phase coil of motor generator 13. Current sensor 18v ​​detects a V-phase current flowing between PCU 12 and motor generator 13, and outputs a V-phase current value, which is a sensor value, to control device 14. Control device 14 can monitor the sensor value of current sensor 18v ​​based on a signal input from current sensor 18v.

[0025] The current sensor 18w is provided between the PCU 12 and the motor generator 13 to detect a W-phase current. The current sensor 18w is provided on a wiring that connects a connection point between the fifth switching element SW5 and the sixth switching element SW6 of the PCU 12 and one end of the W-phase coil of the motor generator 13. The current sensor 18w detects the W-phase current flowing between the PCU 12 and the motor generator 13, and outputs the W-phase current value, which is the sensor value, to the control device 14. The control device 14 can monitor the sensor value of the current sensor 18W based on a signal input from the current sensor 18w.

[0026] The current sensor 19 measures the current of the battery 11. The current sensor 19 is a current sensor provided on a power line connected to the positive terminal of the battery 11. During external charging, the current sensor 119 detects the current supplied to the battery 11 and outputs the current value to the control device 14.

[0027] The control device 14 performs charging control and step-up / step-down control. The charging control is control for charging the battery 11 with power supplied from an external power source. The step-up / step-down control is control for controlling the step-up operation or step-down operation in the PCU 12. In addition, in the charging control, the control device 14 calculates a required current value on the vehicle 2 side, and transmits a current command including the required current value to the charging stand 3. In other words, the control device 14 controls the charging circuit on the vehicle 2 side and the charging circuit on the charging stand 3 side.

[0028] The charging stand 3 includes a DC charging device 31 and a control device 32. The charging stand 3 also includes a communication device that communicates with the vehicle 2.

[0029] The DC charging device 31 is electrically connected to an AC power source (external power source) arranged outside the charging stand 3. In response to a command from the control device 32, the DC charging device 31 converts AC power received from the external power source into DC power and supplies it to the vehicle 2 via a charging cable. The power that can be output from the DC charging device 31 is greater than the power that can be output from an AC charging device. Therefore, when charging the same amount of power, DC quick charging using the DC charging device 31 can complete charging in a shorter time than AC charging using an AC charging device.

[0030] The control device 32 has the same hardware configuration as the control device 14. A signal from a current sensor 33 is input to the control device 32. The current sensor 33 is a current sensor that detects the current in the charging stand 3. The current sensor 33 is provided on the power line closer to the external power source than the DC charging device 31. The control device 32 comprehensively controls other devices in the charging stand 3. The control device 32 controls the DC charging device 31 based on information received from the vehicle 2 via the charging cable or a communication device, and adjusts the power supplied to the vehicle 2. The charging system 1 has a function of transmitting a current command from the vehicle 2 to the charging stand 3. The information received from the vehicle 2 includes the current value of the battery 11. The control device 32 of the charging stand 3 can monitor the sensor value of the current sensor 19 on the on-board battery side.

[0031] In the charging system 1 configured as above, when charging the 800V battery 11 mounted on the vehicle 2 with power supplied from the 400V charging stand 3, the PCU 12 performs step-up / step-down charging. When the voltage of the battery 11 is higher than the voltage of the charging stand 3, the charging system 1 can step-down the voltage of the charging stand 3 to the voltage of the battery 11. Alternatively, the charging system 1 can step-down the voltage of the battery 11 to the voltage of the charging stand 3. At this time, the control device 14 of the vehicle 2 is configured to perform gain correction of the current sensor used in the current feedback control. In the current feedback control, a duty calculated by multiplying the difference between the sensor value and the command value of the current sensors 18u, 18v, and 18w (a value obtained by subtracting the command value from the sensor value) by a correction coefficient is output. Specifically, the control device 14 adds a gain correction sequence for the current sensors 18u, 18v, and 18w immediately after the start of charging.

[0032] 2 and 3, the charging control and the step-up / step-down control performed in the charging system 1 will be described. The control shown in FIG. 2 (charging control) and the control shown in FIG.

[0033] 2, the control device 14 determines whether or not there is a request for gain correction of the current sensors 18u, 18v, and 18w (step S11). In step S11, it is determined whether or not there is a request for gain correction from the step-up / step-down control. When performing the step-up / step-down control, the control device 14 determines whether or not there is a request for gain correction of the current sensors 18u, 18v, and 18w, and if it determines that there is a request for gain correction, it transmits a signal indicating that there is a request for gain correction of the current sensors from the step-up / step-down control to the charging control.

[0034] When it is determined that there is a request for gain correction of the current sensors 18u, 18v, and 18w (step S11: Yes), the control device 14 transmits a VL command (duty) at which the current ripple becomes zero to the step-up / step-down control (step S12). The duty at which the current ripple becomes zero can be specified for three-phase interleaving and two-phase interleaving, as shown in FIG. 4. The horizontal axis in FIG. 4 represents the input voltage / output voltage. The input voltage is the voltage on the low voltage side of the PCU 12. The output voltage is the voltage on the high voltage side of the PCU 12. In addition, if the number of interleaves in which the PCU 12 operates is P, when the current ripple becomes minimum, the relationship "(input voltage / output voltage)=(natural number less than P / P)" is established. For example, when the PCU 12 operates as a two-phase interleave, the duty at which the current ripple becomes zero is "1 / 2". Or, when the PCU12 operates as a three-phase interleave, the duty at which the current ripple is zero is "1 / 3" or "2 / 3." The horizontal axis of Fig. 4 can represent the duty at which the sum of the n-phase current ripple is zero. During three-phase interleave operation, when the "input voltage / output voltage" is "1 / 3" or "2 / 3," an operating point appears at which the current ripple is zero.

[0035] The control device 14 transmits the requested current values ​​for gain correction of the current sensors 18u, 18v, and 18w to the charging stand 3 (step S13). In step S13, the current values ​​for gain correction of the current sensors calculated by the control device 14 are transmitted from the vehicle 2 to the charging stand 3 as requested current values ​​to the charging stand 3. As shown in Fig. 5, the control device 14 changes the current values ​​requested of the charging stand 3 and calculates gain correction coefficients of the current sensors 18u, 18v, and 18w of each phase for each current value. Also, in step S13, charging of the vehicle 2 from the charging stand 3 is started.

[0036] The control device 14 transmits the current sensor information to the step-up / step-down control (step S14). In step S14, the control device 14 transmits the current sensor information with higher accuracy from the current sensor 19 that detects the current of the battery 11 of the vehicle 2 and the current sensor 33 that detects the current of the charging stand 3 to the step-up / step-down control. In step S14, the control device 14 transmits the current value of the battery 11 or the current value of the charging stand 3 to the step-up / step-down control.

[0037] The control device 14 transmits a command to the step-up / step-down control to permit the gain correction of the current sensors 18u, 18v, and 18w to be performed (step S15). In step S15, the permission to perform the gain correction of the current sensors 18u, 18v, and 18w is transmitted to the step-up / step-down control. After the process of step S15 is performed, this control routine ends.

[0038] If it is determined that there is no request for gain correction of the current sensors 18u, 18v, and 18w (step S11: No), the control device 14 transmits a command to the step-up / step-down control to prohibit the gain correction of the current sensors 18u, 18v, and 18w (step S16). In step S16, a command to prohibit the gain correction of the current sensors 18u, 18v, and 18w is transmitted to the step-up / step-down control. After the process of step S16 is performed, this control routine ends.

[0039] As shown in FIG. 3, the control device 14 determines whether or not there is a request for correcting the gains of the current sensors 18u, 18v, and 18w (step S21).

[0040] If it is determined that there is a request for gain correction of the current sensors 18u, 18v, and 18w (step S21: Yes), the control device 14 transmits a requested current value for gain correction of the current sensors 18u, 18v, and 18w to the charging control (step S22). In step S22, a signal indicating that there is a request for gain correction of the current sensors 18u, 18v, and 18w is transmitted from the step-up / step-down control to the charging control.

[0041] The control device 14 performs current feedback control based on the VL command (duty) sent from the charging control (step S23). In step S23, VL is realized by current feedback control based on the VL command received from the charging control. This VL is the voltage on the low-voltage side of the PCU 12. In other words, this VL is the voltage to be measured by the first voltage sensor 16, which is a VL sensor.

[0042] The control device 14 samples the current sensor value based on the current sensor information sent from the charging control (step S24). In step S24, the value of a highly accurate current sensor is sampled. As shown in FIG. 6, the control device 14 samples the current during three-phase interleaving so that the current sampling period is 1 / 3 of the carrier period. Also, in step S24, the current value sampled by the highly accurate current sensor may be received from the charging control. That is, in step S24, the control device 14 may receive the current sensor value from the charging control.

[0043] The control device 14 calculates and stores the gain characteristics of the current sensors 18u, 18v, and 18w of each phase (step S25). In step S25, the control device 14 calculates and stores the gain characteristics of the current sensors 18u, 18v, and 18w of each phase based on the current value sampled by the high-precision current sensor and the required current value for gain correction of the current sensors 18u, 18v, and 18w. The control device 14 calculates the correction coefficient for each phase as shown in FIG. 7.

[0044] As shown in Fig. 7, when the current command is I * [A], the current command for each phase is I * / 3[A]. The following equations (1) to (4) hold for the A, B, and C values ​​of the three-phase total current. A value = (I * x1 / 3xv _gain )+(I * x2 / 3xw _gain ) ···(1) B value = (I * x1 / 3xu _gain)+(I * x2 / 3xv _gain ) ···(2) C value = (I * x2 / 3xu _gain )+(I * x1 / 3xw _gain ) ···(3) A value + B value + C value = I * ×(u _gain +v _gain +w _gain ) ···(4)

[0045] Using the above equations (1) to (4), u _gain , v _gain , w _gain By solving this, we obtain the following equations (5) to (7). u _gain =(1 / I * ) × (2 / 3) × {-A value + (B value / 2) + (2 × C value)} (5) v _gain =(1 / I * )×(2 / 3)×{(A value / 2)+(2×B value)-C value} (6) w _gain =(1 / I * ) × (2 / 3) × {(2 × A value) - B value + (C value / 2)} (7)

[0046] From the above equations (5) to (7), the correction coefficient K for each phase is expressed by the following equations (8) to (10). Ku=1 / u _gain (8) Kv=1 / v _gain (9) Kw=1 / w _gain (10)

[0047] For example, the current command I * [A] is 700[A], u _gain is "1.3", v _gain is "1.0", w _gain is "1.0", the A value will be 750[A], the B value will be 825[A], and the C value will be 900[A].

[0048] Then, the control device 14 transitions the gain correction state of the current sensors 18u, 18v, 18w to completion (step S26). In step S26, the gain correction of the current sensors 18u, 18v, 18w is performed using the correction coefficient K calculated in step S25. In step S25, the control device 14 calculates the gain of the current sensors 18u, 18v, 18w of each phase according to the current ripple detected during charging in step S24, calculates a correction coefficient based on the gain of the current sensors 18u, 18v, 18w of each phase, and corrects the gain of the current sensors 18u, 18v, 18w of each phase using the correction coefficient. After performing the process of step S26, this control routine ends.

[0049] If it is determined that there is no request for gain correction of the current sensor (step S21: No), the control device 14 transitions to normal control (step S27). After performing the process of step S27, this control routine ends.

[0050] As shown in Fig. 2 and Fig. 3, the control device 14 performs charging at a duty where the current ripple due to interleaving becomes zero as a gain correction sequence immediately after the start of charging. Then, since the current ripple detected during this charging is only the gain of the current sensor, the control device 14 calculates the gain of the current sensors 18u, 18v, and 18w of each phase, and performs gain correction or normal charging. During three-phase interleaving, the control device 14 performs gain correction in a state where no ripple is carried on the total current of the three phases. For example, during three-phase interleaving, when the current of the charging stand 3 is 750A, the duty is 2 / 3 (0.666), and the gain error of the u-phase current sensor is 30%, the control device 14 can correct the gain of the current sensors 18u, 18v, and 18w used in current feedback control by performing gain correction of the current sensors 18u, 18v, and 18w. [Explanation of symbols]

[0051] 1 Charging System 2 Vehicles 3. Charging stand 11 Battery 12 PCU 13 Motor generator 14 Control device 15 Capacitor 16 First voltage sensor 17 Second voltage sensor 18u,18v,18w,19 Current Sensor 31 DC charging device 32 Control device 33 Current Sensor

Claims

[Claim 1] A control device for a charging circuit that boosts and reduces the voltage of power supplied from an external power source and supplies the power to an in-vehicle battery, When starting charging the vehicle-mounted battery from the external power supply, charging is started at an operating point where a current ripple becomes zero; During the charging, a current feedback control is performed using a sensor value of a current sensor that detects the current; The gain of the current sensor is corrected according to the current ripple detected during the charging. A control device for a charging circuit.

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