On-vehicle control device

Abstract

To more appropriately remove noise superimposed on motor current.SOLUTION: An electric vehicle includes: a battery; a motor; an inverter that drives the motor; a step-up circuit that boosts the power from the battery and supplies it to the inverter; a current sensor unit that unifies a reactor current sensor for detecting a reactor current flowing through a reactor of the step-up circuit and a motor current sensor for detecting a three-phase motor current flowing through the motor; and an on-vehicle control device that controls the step-up circuit and the inverter on the basis of the reactor current and the motor current detected by the current sensor unit. When a rotation speed of the motor is less than a predetermined rotation speed, the on-vehicle control device increases a time constant of a noise filter used when inputting the motor current, compared to when the rotation speed of the motor is greater than or equal to the predetermined rotation speed.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to an in-vehicle control device, and more particularly to an in-vehicle control device that controls a boost circuit and an inverter based on a reactor current and a motor current. [Background technology]

[0002] Conventionally, as this type of in-vehicle control device, a control unit that controls two converters connected in parallel has been proposed (for example, see Patent Document 1). This control unit selects and drives the converter in order of the best cooling performance for the reactor of each of the two converters. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-106753 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a control device mounted on an electric vehicle equipped with a battery, a boost circuit, an inverter, and a motor, the boost circuit and the inverter are controlled using the reactor current flowing through the reactor of the boost circuit and the three-phase motor current flowing through the motor. A current sensor that detects the reactor current and a current sensor that detects the three-phase motor current are unitized and connected to the control device for the purpose of efficient manufacturing. In such a control device, a noise removal filter is used to capture the motor current because the switching noise of the boost circuit is superimposed and conducted on the detection signal line of the reactor current, and is superimposed on the detection signal line of the motor current. However, when the motor rotation speed is low, there are cases where the noise cannot be removed.

[0005] The main object of the in-vehicle control device of the present disclosure is to more appropriately remove noise superimposed on the motor current. [Means for solving the problem]

[0006] The vehicle control device of the present disclosure employs the following means to achieve the above-mentioned main object.

[0007] The in-vehicle control device of the present disclosure includes: An on-board control device for an electric vehicle including a battery, a motor, an inverter for driving the motor, a boost circuit for boosting power from the battery and supplying the boosted power to the inverter, a current sensor unit incorporating a reactor current sensor for detecting a reactor current flowing through a reactor of the boost circuit and a motor current sensor for detecting a three-phase motor current flowing through the motor, and an on-board control device for controlling the boost circuit and the inverter based on the reactor current and the motor current detected by the current sensor unit, When the rotation speed of the motor is less than a predetermined rotation speed, the time constant of a noise filter used when inputting the motor current is made larger than when the rotation speed of the motor is equal to or greater than the predetermined rotation speed. It is characterized by:

[0008] The vehicle control device disclosed herein is mounted on an electric vehicle including a battery, a motor, an inverter for driving the motor, and a boost circuit for boosting the power from the battery and supplying it to the inverter. The vehicle control device is connected to a current sensor unit that combines a reactor current sensor for detecting a reactor current flowing through a reactor of the boost circuit and a motor current sensor for detecting a three-phase motor current flowing through the motor, and controls the boost circuit and the inverter based on the reactor current and the motor current detected by the current sensor unit. When the rotation speed of the motor is less than a predetermined rotation speed, the time constant of the noise filter used when inputting the motor current is made larger than when the rotation speed of the motor is equal to or greater than the predetermined rotation speed. When the rotation speed of the motor is low, the switching frequency of the boost circuit is also low, so by making the time constant of the noise filter larger, it is possible to more effectively remove noise superimposed on the detection signal line of the motor current due to switching of the boost circuit. This makes it possible to more appropriately remove noise superimposed on the motor current. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram showing an outline of the configuration of an electric vehicle 20 equipped with an on-board control device according to an embodiment of the present disclosure. [Diagram 2] 5 is a flowchart showing an example of a noise filter time constant setting process executed by a motor electronic control unit 50. [Diagram 3] FIG. 4 is an explanatory diagram showing an example of a map showing the relationship between the rotation speed Nm of a motor and the time constant of a noise filter, which is used as a first map or a second map. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Next, a mode (embodiment) for carrying out the present disclosure will be described. Fig. 1 is a configuration diagram showing an outline of the configuration of an electric vehicle 20 equipped with an on-board control device as one embodiment of the present disclosure. As shown in the figure, the electric vehicle 20 of the embodiment includes a battery 22, a system main relay (SMR) 24, a boost converter 26, a capacitor 28, an inverter (INV) 30, a motor MG1, a motor MG2, a current sensor unit 40, and a motor electronic control unit (MGECU) 50.

[0011] Battery 22 is configured as, for example, a lithium ion secondary battery or a nickel-metal hydride secondary battery with a rated voltage of several hundred volts, and is connected to boost converter 26 via a low-voltage side power line. System main relay 24 is attached to the low-voltage side power line that connects battery 22 and boost converter 26.

[0012] The boost converter 26 is connected to the high-voltage power line and the low-voltage power line connected to the inverter 30, and includes two switching elements, transistors Tr1 and Tr2, two diodes D1 and D2 connected in parallel to the two transistors Tr1 and Tr2, and a reactor L. The transistor Tr1 is connected to the positive line of the high-voltage power line. The transistor Tr2 is connected to the transistor Tr1 and the negative line of the high-voltage power line and the low-voltage power line. The reactor L is connected to the connection point of the two transistors Tr1 and Tr2 and the positive line of the low-voltage power line. The boost converter 26 boosts the power of the low-voltage power line and supplies it to the high-voltage power line, or reduces the power of the high-voltage power line and supplies it to the low-voltage power line by adjusting the ratio of the on-time of the transistors Tr1 and Tr2 by the motor electronic control unit 50. A smoothing capacitor 28 is attached to the positive and negative lines of the high-voltage power line.

[0013] The inverter 30 is used to drive the motors MG1 and MG2 and is connected to the boost converter 26 via a high-voltage power line. The inverter 30 is composed of two inverter circuits that drive the two motors MG1 and MG2. The two inverter circuits are preferably configured as well-known inverter circuits having six switching elements (transistors) and six diodes connected in parallel to each of the six switching elements.

[0014] The motors MG1 and MG2 are configured as, for example, synchronous generator motors, and have a rotor with a permanent magnet embedded in the rotor core and a stator with a three-phase coil wound around the stator core. The rotor of the motor MG2 is connected to a drive shaft connected to drive wheels (not shown) via a differential gear. If the electric vehicle 20 is an electric vehicle without an engine, the motor MG1 is connected to a drive shaft different from the drive shaft to which the motor MG2 is connected, and if the electric vehicle 20 is a hybrid vehicle with an engine, the motor MG1 is connected to the engine, or similarly, if the electric vehicle 20 is a hybrid vehicle, the motor MG1 is connected to a sun gear of a planetary gear that is connected to the output shaft and drive shaft of the engine.

[0015] The current sensor unit 40 has a reactor current sensor 42 that detects the current (reactor current) IL of the reactor L, a first motor current sensor 44 consisting of three sensors or two sensors that detects the three-phase current (first motor current I1uvw) flowing through the motor MG1, and a second motor current sensor 46 consisting of three sensors or two sensors that detects the three-phase current (second motor current I2uvw) flowing through the motor MG2, and is configured as a single assembly (ASSY) and attached to the motor electronic control unit 50.

[0016] The motor electronic control unit 50 includes an MG1 microcomputer 52 for driving and controlling the motor MG1, and an MG2 microcomputer 54 for driving and controlling the motor MG2. The MG1 microcomputer 52 receives the reactor current IL and the first motor current I1uvw from the current sensor unit 40, and controls the switching of the switching elements of the inverter circuit for the motor MG1 of the inverter 30 for feedback control of the motor MG1 based on the torque command Tm1* of the motor MG1, the reactor current IL, the voltage of the high-voltage side power line, and the first motor current I1uvw. A soft noise filter for removing noise is attached to the input circuit of the first motor current I1uvw of the MG1 microcomputer 52. The MG1 microcomputer 52 receives the rotational position from a rotational position sensor (not shown) attached to the motor MG1, and calculates the rotational speed Nm1 of the motor MG1 based on this rotational position. The MG2 microcomputer 54 inputs the reactor current IL and the second motor current I2uvw from the current sensor unit 40, and controls the switching of the switching elements of the inverter circuit for motor MG2 of the inverter 30 for feedback control of motor MG2 based on the torque command Tm2* of motor MG2, the reactor current IL, the voltage of the high-voltage side power line, and the second motor current I2uvw. The MG2 microcomputer 54 inputs the rotational position from a rotational position sensor (not shown) attached to motor MG2, and calculates the rotational speed Nm2 of motor MG2 based on this rotational position.

[0017] Next, the operation of the electric vehicle 20 of the embodiment thus configured, particularly the operation of removing noise occurring in the signal lines of the first motor current I1uvw and the second motor current I2uvw due to switching of the transistors Tr1 and Tr2 of the boost converter 26, will be described. Noise caused by switching of the transistors Tr1 and Tr2 of the boost converter 26 is superimposed on the signal line of the reactor current IL and conducted. The reactor current sensor 42, the first motor current sensor 44, and the second motor current sensor 46 are assembled as a current sensor unit 40 and attached to the motor electronic control unit 50, so that the signal line of the reactor current IL is close to the signal lines of the first motor current I1uvw and the second motor current I2uvw. For this reason, the noise caused by switching of the boost converter 26 superimposed on the signal line of the reactor current IL is also superimposed on the signal lines of the first motor current I1uvw and the second motor current I2uvw. 2 is a flowchart showing an example of a noise filter time constant setting process executed by the motor electronic control unit 50 to set the time constant of a noise filter that removes noise superimposed on the signal lines of the first motor current I1uvw and the second motor current I2uvw due to switching of the boost converter 26. This process is repeatedly executed at predetermined time intervals.

[0018] When the noise filter time constant setting process is executed, the motor electronic control unit 50 first executes a process of inputting the rotation speeds Nm1, Nm2 of the motors MG1, MG2 (step S100). This process is a process of inputting the rotation speeds Nm1, Nm2 of the motors MG1, MG2 calculated by the MG1 microcomputer 52 and the MG2 microcomputer 54.

[0019] Next, the time constants τ1 and τ2 of the noise filters of the motors MG1 and MG2 are set based on the rotation speeds Nm1 and Nm2 of the motors MG1 and MG2 (step S110). In the embodiment, the time constant τ1 for the motor MG1 is set by determining the relationship between the rotation speed Nm1 of the motor MG1 and the time constant τ1 of the noise filter in advance by experiments, machine learning, or the like, and storing it as a first map, and deriving the corresponding time constant τ1 from the first map when the rotation speed Nm1 of the motor MG1 is given. Similarly, the time constant τ2 for the motor MG2 is set by determining the relationship between the rotation speed Nm2 of the motor MG2 and the time constant τ2 of the noise filter in advance by experiments, machine learning, or the like, and storing it as a second map, and deriving the corresponding time constant τ2 from the second map when the rotation speed Nm2 of the motor MG2 is given. FIG. 3 shows an example of a map showing the relationship between the rotation speed Nm of the motor and the time constant τ of the noise filter used as the first map or the second map. In the figure, the thick solid line indicates the relationship between the motor rotation speed Nm and the time constant τ of the noise filter, the dashed line indicates the relationship between the time constant of the noise filter required to remove noise caused by switching of the boost converter 26, the dashed line indicates the time constant of the noise filter regardless of the motor rotation speed Nm, and the thin solid line indicates the relationship between the motor rotation speed Nm and the maximum value of the motor torque. Since the time constant τ of the noise filter only needs to be larger than the dashed line in the figure (upper side in the figure), by setting the time constant τ to be larger in the low motor rotation speed Nm region than in the high motor rotation speed region as shown by the thick solid line in the figure, it is possible to more appropriately remove noise superimposed on the detection signal lines of the first motor current Iuvw and the second motor current I2uvw caused by switching of the boost converter 26. In the embodiment, the thick solid lines in the figure are used as the first map and the second map.

[0020] Once the time constants τ1, τ2 of the noise filters of the motors MG1, MG2 have been set in this manner, the set time constants are applied to the noise filter for the motor MG1 and the noise filter for the motor MG2 (step S120), and this process ends.

[0021] In the motor electronic control unit 50 of the electric vehicle 20 of the embodiment described above, the time constants τ1, τ2 of the noise filter that removes noise caused by switching of the boost converter 26 and superimposed on the signal lines of the first motor current 1uvw and the second motor current I2uvw are set to be larger in the low range of the rotation speeds Nm1, Nm2 of the motors MG1, MG2 than in the high range. This makes it possible to more appropriately remove noise superimposed on the detection signal lines of the first motor current 1uvw and the second motor current I2uvw due to the switching of the boost converter 26.

[0022] In the electric vehicle 20 of the embodiment, the motor electronic control unit 50 executes the noise filter time constant setting process, but the MG1 microcomputer 52 and the MG2 microcomputer 54 of the motor electronic control unit 50 may each execute the noise filter time constant setting process.

[0023] In the electric vehicle 20 of the embodiment, the relationship between the rotation speeds Nm1, Nm2 of the motors MG1, MG2 and the time constants τ1, τ2 of the noise filters is such that the time constant τ increases linearly as the motor rotation speed Nm decreases, as shown by the thick solid line in Fig. 3. However, the relationship may be such that the time constant τ increases in a stepped manner as the motor rotation speed Nm decreases, as long as it is larger than the dashed dotted line in Fig. 3. In this case, the number of steps may be one.

[0024] Although the electric vehicle 20 of the embodiment is provided with two motors, the motor MG1 and the motor MG2, it may be provided with only a single motor, or may be provided with three or more motors.

[0025] The following describes the relationship between the main elements of the embodiment and the main elements of the invention described in the Summary of the Invention section. The battery 22 corresponds to a "battery", the motors MG1, MG2 correspond to a "motor", the inverter 30 corresponds to an "inverter", the boost converter 26 corresponds to a "boost circuit", the reactor current sensor 42 corresponds to a "reactor current sensor", the first motor current sensor 44 and the second motor current sensor 46 correspond to "motor current sensors", the current sensor unit 40 corresponds to a "current sensor unit", and the motor electronic control unit 50 corresponds to an "on-vehicle control device".

[0026] Note that the correspondence between the main elements of the embodiment and the main elements of the invention described in the Means for Solving the Problem column does not limit the elements of the invention described in the Means for Solving the Problem column, since the embodiment is an example for specifically explaining the form for implementing the invention described in the Means for Solving the Problem column. In other words, the interpretation of the invention described in the Means for Solving the Problem column should be made based on the description in that column, and the embodiment is merely a specific example of the invention described in the Means for Solving the Problem column.

[0027] The present disclosure has been described above using embodiments, but the present disclosure is not limited to these embodiments in any way, and it goes without saying that the present disclosure can be embodied in various forms without departing from the gist of the present disclosure. [Industrial Applicability]

[0028] The present disclosure can be used in the manufacturing industry of in-vehicle control devices, etc. [Explanation of symbols]

[0029] 20 electric vehicle, 22 battery, 24 system main relay, 26 boost converter, 28 capacitor, 30 inverter, 40 current sensor unit, 42 reactor current sensor, 44 first motor current sensor, 46 first motor current sensor, 50 motor electronic control unit, 52 MG1 microcomputer, 54 MG2 microcomputer, L reactor, MG1, MG2 motors, Tr1, Tr2 transistors.

Claims

1. An on-board control device for an electric vehicle including a battery, a motor, an inverter for driving the motor, a boost circuit for boosting power from the battery and supplying the boosted power to the inverter, a current sensor unit incorporating a reactor current sensor for detecting a reactor current flowing through a reactor of the boost circuit and a motor current sensor for detecting a three-phase motor current flowing through the motor, and an on-board control device for controlling the boost circuit and the inverter based on the reactor current and the motor current detected by the current sensor unit, When the rotation speed of the motor is less than a predetermined rotation speed, the time constant of a noise filter used when inputting the motor current is made larger than when the rotation speed of the motor is equal to or greater than the predetermined rotation speed.

2. An in-vehicle control device comprising:

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