CN108569145B

CN108569145B - Control device for electric vehicle and leakage detection state determination method

Info

Publication number: CN108569145B
Application number: CN201810182834.7A
Authority: CN
Inventors: 小川泰文; 石川修; 北川润
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2017-03-13
Filing date: 2018-03-06
Publication date: 2021-06-22
Anticipated expiration: 2038-03-06
Also published as: JP6324570B1; JP2018152987A; CN108569145A

Abstract

The invention provides a control device of an electric vehicle and a leakage detection state determination method, which can determine the operation state of a leakage detection device arranged in the electric vehicle. The invention is composed of: in order to control the boost voltage of the boost converter of the power drive unit, a signal of a specific frequency band is extracted as an extraction signal by performing a band-pass filtering process on a 1 st boost voltage command calculated based on at least a motor torque command and a motor rotation speed, and the amplitude of the extraction signal is compared with a preset amplitude value to determine whether or not an operation abnormality occurs in the leakage detecting device.

Description

Control device for electric vehicle and leakage detection state determination method

Technical Field

The present invention relates to a control device for an electric vehicle and an electric leakage detection state determination method for determining an operation state of an electric leakage detection device provided in the electric vehicle.

Background

In recent years, attention has been paid to hybrid vehicles, electric vehicles, and the like as electric vehicles taking energy saving, environment, and the like into consideration. In addition to a conventional engine, a hybrid vehicle uses an electric motor as a power source, and an electric vehicle uses an electric motor as a power source. Both hybrid vehicles and electric vehicles convert direct current stored in a battery into alternating current using an inverter circuit, and drive an electric motor using the alternating current to travel.

Here, in an electric vehicle including an inverter that drives a motor and a boost converter that boosts a voltage from a battery and supplies the boosted voltage to the inverter, the following method is proposed as a method of controlling the boost converter. Namely, the following means is proposed: a target value of a boost voltage suitable for efficient operation of the motor is calculated from the rotation speed and the target output torque of the motor, and the boost converter is controlled so that the boost voltage becomes the target value (see, for example, patent document 1).

In an electric vehicle, a high-voltage battery of more than 100V is used to drive a motor, a vehicle body ground such as a vehicle body is electrically connected to a negative terminal of the high-voltage battery, and an insulation process is performed between the negative terminal of the high-voltage battery and the vehicle body ground. Therefore, the following system is proposed: insulation resistance between the negative terminal of the high-voltage battery and the vehicle body ground is monitored, and when the insulation resistance becomes a set value or less, a warning is given to the driver (see, for example, patent document 2).

In an electric vehicle, a Y capacitor may be disposed between a vehicle body and a high-voltage portion in order to cope with noise generated by an inverter for driving a motor, a boost converter for supplying a boosted voltage to the inverter, and the like (see, for example, patent document 3).

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 3797361

Patent document 2: japanese patent No. 4572777

Patent document 3: japanese patent No. 4635710

Disclosure of Invention

Technical problem to be solved by the invention

Here, since the value of the boosted voltage supplied from the boost converter to the inverter depends on the motor rotation speed, the torque, and the like, the boosted voltage of the boost converter changes due to a fluctuation in the motor torque, a fluctuation in the motor rotation speed, and the like caused by a sudden accelerator depression. In this case, depending on a change in the boosted voltage, the Y capacitor for noise removal may be energized by the noise current. In addition, the noise current also affects the charging and discharging of the coupling capacitor of the leakage detecting device. In view of the structure, the leakage detecting device detects a decrease in insulation resistance, that is, leakage, by charging and discharging the coupling capacitor.

As described above, if the boost voltage of the boost converter periodically fluctuates due to fluctuations in the motor torque, fluctuations in the motor rotational speed, or the like, the charging and discharging of the coupling capacitor is affected, and there is a possibility that the leakage detection device erroneously detects leakage. Therefore, in order to ensure the reliability of the detection structure of the leakage detecting device, a technique for determining whether or not the leakage detecting device has a leakage misdetection is required.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a control device for an electric vehicle and a leakage detection state determination method that can determine an operating state of a leakage detection device provided in the electric vehicle.

Technical scheme for solving technical problem

A control device for an electric vehicle according to the present invention is a control device for determining an operation state of a leakage detecting device provided in an electric vehicle including a motor and a power drive unit for driving the motor, wherein the power drive unit includes: a motor inverter that drives the motor by being controlled by a motor torque command for controlling the motor; and a boost converter that boosts a voltage supplied from the dc power supply by being controlled by the 1 st boost voltage command, and supplies the boosted voltage to the motor inverter as a boost voltage, the control device including: a 1 st step-up voltage command output unit that acquires a motor torque command and a motor rotation speed of the motor, calculates and outputs a 1 st step-up voltage command based on the acquired motor torque command and motor rotation speed; and a leakage detection state determination unit that performs a band-pass filtering process on the 1 st boosted voltage command output by the 1 st boosted voltage command output unit to extract a signal of a specific frequency band as an extraction signal, calculates an amplitude of the extraction signal, and compares the calculated amplitude with a preset amplitude value to determine whether or not an operation abnormality occurs in the leakage detection device.

A leakage detection state determination method for an electric vehicle according to the present invention is a method for determining an operation state of a leakage detection device provided in an electric vehicle including a motor and a power drive unit that drives the motor, wherein the power drive unit includes: a motor inverter that drives the motor by being controlled by a motor torque command for controlling the motor; and a step-up converter that is controlled by the 1 st step-up voltage command to step up a voltage supplied from the dc power supply and supplies the stepped-up voltage to the motor inverter as a step-up voltage, the method for determining a leakage detection state of an electric vehicle comprising: acquiring a motor torque command and a motor rotation speed of the motor, and calculating a 1 st step-up voltage command based on the acquired motor torque command and motor rotation speed; and a step of performing band-pass filtering processing on the calculated 1 st boosted voltage command to extract a signal of a specific frequency band as an extraction signal, calculating the amplitude of the extraction signal, and comparing the amplitude obtained by the calculation with a preset amplitude value to determine whether the leakage detecting device has an abnormal operation.

Effects of the invention

According to the present invention, a control device for an electric vehicle and a leakage detection state determination method that can determine an operation state of a leakage detection device provided in the electric vehicle can be obtained.

Drawings

Fig. 1 is a schematic configuration diagram of an electric vehicle in embodiment 1 of the present invention.

Fig. 2 is a configuration diagram showing a control device in embodiment 1 of the present invention.

Fig. 3 is a graph showing an example of motor output characteristics of the motor of fig. 1.

Fig. 4 is a block diagram showing the leakage detection state determination unit shown in fig. 2.

Fig. 5 is a flowchart showing a series of operations of the control device in embodiment 1 of the present invention.

Fig. 6 is a configuration diagram showing a control device in embodiment 2 of the present invention.

Fig. 7 is a configuration diagram showing the 2 nd boosted voltage command output unit in fig. 6.

Fig. 8 is a configuration diagram showing a control device in embodiment 3 of the present invention.

Detailed Description

Hereinafter, a control device for an electric vehicle and a leakage detection state determination method according to the present invention will be described based on preferred embodiments with reference to the drawings. In the description of the drawings, the same or corresponding portions are denoted by the same reference numerals, and redundant description is omitted.

Embodiment 1.

Fig. 1 is a schematic configuration diagram of an electric vehicle in embodiment 1 of the present invention. In fig. 1, the electric vehicle includes an engine 1, a generator 2, a motor 3, tires 4, a power drive unit 5, a battery 6 as one example of a direct-current power supply, a leakage detection device 7, a control device 8, and a vehicle controller 9.

The engine 1 is driven by burning gasoline to generate torque. The generator 2 receives torque generated by the engine 1 to generate ac power. When the engine 1 is stopped, the generator 2 is caused to generate torque by the ac power supplied from the generator inverter 52, and the engine 1 is thereby started.

The motor 3 is driven by an alternating current supplied from a motor inverter 51 described later to generate a torque. The motor 3 generates torque to drive the tire 4, thereby driving the vehicle.

In fig. 1, the engine 1 and the generator 2 are directly connected to each other as an example, but a gear or the like for transmitting power may be provided therebetween. Similarly, the motor 3 and the tire 4 are directly connected to each other as an example, but a gear or the like for transmitting power may be provided therebetween.

The power drive unit 5 is for driving the generator 2 and the motor 3, and includes a motor inverter 51, a generator inverter 52, and a boost converter 53.

The motor inverter 51 drives the motor 3 by being controlled by a motor torque command, which will be described later. Specifically, the motor inverter 51 includes a plurality of switching elements (not shown), and converts direct current power into alternating current power by switching on and off of each switching element, and supplies the alternating current power to the motor 3, thereby powering the motor 3. Further, during regenerative driving of the motor 3, the motor inverter 51 converts alternating current generated by the motor 3 into direct current.

The generator inverter 52 drives the generator 2 by being controlled by a generator torque command described later. Specifically, the generator inverter 52 includes a plurality of switching elements (not shown), converts direct current power into alternating current power by switching on and off of each switching element, and supplies the alternating current power to the generator 2. Further, the alternating current generated by the generator 2 is converted into direct current.

The boost converter 53 boosts the voltage supplied from the battery 6 by being controlled by a 1 st boosted voltage command or a 2 nd boosted voltage command, which will be described later, and supplies the boosted voltage as a boosted voltage to the motor inverter 51 and the generator inverter 52, respectively. Specifically, the boost converter 53 includes a switching element (not shown), boosts a voltage of the battery 6 (hereinafter, referred to as a battery voltage) by switching on and off of the switching element, and applies the boosted voltage, that is, a boosted voltage to the motor inverter 51 and the generator inverter 52.

The battery 6 stores dc power and can supply a voltage of 100V or more to the boost converter 53. The battery 6 is constituted by, for example, a lithium ion secondary battery, a nickel hydrogen secondary battery, or the like.

The electrical leakage detection device 7 monitors the insulation resistance between the terminal of the electrically connected battery 6 and a vehicle body ground such as a vehicle body. The terminal of the battery 6 electrically connected to the vehicle body ground is either a negative terminal or a positive terminal of the battery 6. When the monitored insulation resistance becomes equal to or less than a preset value, the leakage detection device 7 detects the occurrence of leakage, and outputs the detection result to the vehicle controller 9.

The above-described function of the electrical leakage detection device 7 can be realized by applying the conventional technique described in patent document 2, for example, and therefore, a detailed description of the configuration is omitted here.

The control device 8 drives the motor 3 and the generator 2 by controlling the motor inverter 51, the generator inverter 52, and the boost converter 53 based on the motor torque command and the generator torque command input from the vehicle controller 9.

The vehicle controller 9 is connected to the Control device 8 so as to be able to communicate with the Control device by communication means such as CAN communication (Control Area Network). The vehicle controller 9 outputs a motor torque command for controlling the electric motor 3 and a generator torque command for controlling the generator 2 to the control device 8. When the occurrence of electric leakage is detected by the electric leakage detection device 7, the vehicle controller 9 lights a warning lamp to the driver of the vehicle.

The control device 8 and the vehicle controller 9 are realized by, for example, a microcomputer that executes arithmetic processing, a ROM (Read Only Memory) that stores data such as program data and fixed value data, and a RAM (Random Access Memory) that updates the stored data and can sequentially rewrite the data.

Next, the control device 8 will be further described with reference to fig. 2. Fig. 2 is a configuration diagram showing the control device 8 in embodiment 1 of the present invention. In fig. 2, the control device 8 includes a motor control unit 81, a generator control unit 82, a boost converter control unit 83, a 1 st boost voltage command output unit 84, a 2 nd boost voltage command output unit 85, and a leakage detection state determination unit 86.

The motor control unit 81 is supplied with the detection results of a rotation angle sensor provided in the motor 3 for detecting the rotation angle of the motor 3 and the detection results of three-phase current sensors provided in the motor inverter 51 for detecting three-phase currents flowing through the motor 3.

The motor control unit 81 controls the motor inverter 51 so that the torque generated by the motor 3 matches the motor torque command input from the vehicle controller 9, using the rotation angle input from the rotation angle sensor and the information of the three-phase currents input from the three-phase current sensors. The motor control unit 81 calculates the rotation speed of the motor 3 (hereinafter referred to as motor rotation speed) from the rotation angle input from the rotation angle sensor, and outputs the motor rotation speed to the 1 st step-up voltage command output unit 84.

The detection result of the rotation angle sensor provided in the generator 2 for detecting the rotation angle of the generator 2 and the detection result of the three-phase current sensor provided in the generator inverter 52 for detecting the three-phase current flowing through the generator 2 are input to the generator control unit 82.

The generator control unit 82 controls the generator inverter 52 so that the torque generated by the generator 2 matches the generator torque command input from the vehicle controller 9, using the rotation angle input from the rotation angle sensor and the information of the three-phase currents input from the three-phase current sensors. The generator control unit 82 calculates the rotation speed of the generator 2 (hereinafter referred to as the generator rotation speed) from the rotation angle input from the rotation angle sensor, and inputs the generator rotation speed to the 1 st step-up voltage command output unit 84.

In embodiment 1, the case where the control command for controlling each of the motor 3 and the generator 2 is a torque command is exemplified, but the form of the control command is not limited to the torque command and may be, for example, a rotational speed command.

The boost converter control unit 83 controls the boost converter 53 so that the boosted voltage of the boost converter 53 becomes the boosted voltage command input from the leakage detection state determination unit 86.

The 1 st step-up voltage command output unit 84 calculates a 1 st step-up voltage command based on the motor torque command and the generator torque command input from the vehicle controller 9, the motor rotation speed input from the motor control unit 81, and the generator rotation speed input from the generator control unit 82, and outputs the 1 st step-up voltage command to the electric leakage detection state determination unit 86.

Here, a method of calculating a boosted voltage command for controlling the boosted voltage of the boost converter 53 using the motor torque command, the generator torque command, the motor rotation speed, and the generator rotation speed is known, and for example, the following method may be employed.

Specifically, a map is prepared in advance in which the motor torque command, the generator torque command, the motor rotational speed, and the generator rotational speed are associated with the step-up voltage command so that the loss of the entire motor 3, the generator 2, the motor inverter 51, and the generator inverter 52 is minimized. Next, the 1 st boosted voltage command output unit 84 calculates a boosted voltage command corresponding to the motor torque command and the generator torque command input from the vehicle controller 9, the motor rotation speed input from the motor control unit 81, and the generator rotation speed input from the generator control unit 82, based on the map, and sets the boosted voltage command as the 1 st boosted voltage command.

As described above, the 1 st step-up voltage command output unit 84 acquires the motor torque command, the motor rotation speed, the generator torque command, and the generator rotation speed, and calculates and outputs the 1 st step-up voltage command based on the acquired motor torque command, the acquired motor rotation speed, the acquired generator torque command, and the acquired generator rotation speed.

The 2 nd boosted voltage command output unit 85 outputs a preset 2 nd boosted voltage command to the leakage current detection state determination unit 86. The 2 nd boosted voltage command is used to control the boosted voltage of the boost converter 53 when it is determined that the operation of the leakage detecting device 7 is abnormal, that is, when the leakage detecting device 7 erroneously detects leakage.

Next, a method of setting the value of the 2 nd step-up voltage command will be described. The 2 nd step-up voltage command is set to a larger value of the minimum step-up voltage required for the motor 3 to generate the maximum output and the minimum step-up voltage required for the generator 2 to generate the maximum output.

Here, the relationship between the dc voltage [ V ] applied to the motor inverter 51 by the boost converter 53 and the motor output (also referred to as motor mechanical output) [ kW ] will be described with reference to fig. 3. Fig. 3 is a graph showing an example of motor output characteristics of the motor 3 of fig. 1.

In fig. 3, the horizontal axis represents the motor rotation speed, and the vertical axis represents the motor output. The motor output is an output calculated from the motor torque and the motor rotation speed. In fig. 3, the motor output is illustrated in a case where the dc voltage applied to the motor inverter 51 is 100V, 200V, or 300V.

In general, when the motor 3 and the motor inverter 51 are combined, as shown in fig. 3, the motor output increases in accordance with the magnitude of the dc voltage applied to the motor inverter 51. As shown in fig. 3, the fact that the motor output is high at the same motor rotation speed means that a large torque can be output at the same motor rotation speed. With such characteristics, the dc voltage required to achieve the maximum output determined in designing the motor may vary depending on the type of motor used, and may also vary between the motor 3 and the generator 2.

The maximum output of the motor 3 mounted on the vehicle is determined in advance, and the value of the minimum boost voltage required to generate the maximum output of the motor 3 is determined based on the value of the maximum output. For example, when the maximum output of the motor 3 is 200kW, the minimum step-up voltage required for the motor 3 to generate the maximum output is 500V.

Similarly, the maximum output of the generator 2 mounted on the vehicle is determined in advance, and the value of the minimum step-up voltage required to generate the maximum output in the motor 3 is determined based on the value of the maximum output. For example, when the maximum output of the generator 2 is 100kW, the minimum step-up voltage required for the generator 2 to generate the maximum output is 700V.

For example, as described above, when the maximum output of the motor 3 is 200kW and the maximum output of the generator 2 is 100kW, the 2 nd step-up voltage command is set to 700V.

As is clear from the above, the 1 st step-up voltage command is a variable value that depends on the motor torque command and the motor rotation speed, whereas the 2 nd step-up voltage command is a fixed value that does not depend on the motor torque command and the motor rotation speed.

Thus, the minimum step-up voltage that can generate both the maximum output of the motor 3 and the maximum output of the generator 2 is set as the 2 nd step-up voltage command, and when it is determined that an abnormality has occurred in the operation of the electrical leakage detection device 7, the step-up voltage of the step-up converter 53 is controlled using the 2 nd step-up voltage command. Therefore, even if the electric leakage detection device 7 falls into a state in which the electric leakage may be erroneously detected, the electric vehicle does not have a situation in which the torque outputs of the motor 3 and the generator 2 are insufficient.

The electric leakage detection state determination unit 86 determines the electric leakage detection state in which it is determined whether or not an abnormality has occurred in the operation of the electric leakage detection device 7, and outputs any one of the 1 st boosted voltage command input from the 1 st boosted voltage command output unit 84 and the 2 nd boosted voltage command input from the 2 nd boosted voltage command output unit 85 to the boost converter control unit 83 as a boosted voltage command based on the determination result.

If it is determined that the operation of the electrical leakage detection device 7 is abnormal, the electrical leakage detection state determination unit 86 outputs the 2 nd step-up voltage command to the step-up converter control unit 83 as a step-up voltage command. On the other hand, if the electrical leakage detection state determination unit 86 determines that there is no abnormality in the operation of the electrical leakage detection device 7, it outputs the 1 st boosted voltage command to the boost converter control unit 83 as the boosted voltage command.

Next, the leakage current detection state determination unit 86 will be further described with reference to fig. 4. Fig. 4 is a block diagram showing the leakage current detection state determination unit 86 in fig. 2. In fig. 4, the leak detection state determination unit 86 includes a frequency component extraction unit 861, an amplitude extraction unit 862, and a determination unit 863.

The frequency component extraction unit 861 performs band-pass filtering processing on the 1 st boosted voltage command input from the 1 st boosted voltage command output unit 84, and extracts only a signal of a specific frequency band as an extraction signal.

The amplitude extractor 862 calculates the amplitude of the extracted signal extracted by the frequency component extractor 861. Specifically, the amplitude extracting unit 862 acquires the maximum amplitude value and the minimum amplitude value of the extracted signal for a preset time period, for example, a period of 100ms, and calculates a value obtained by subtracting the minimum amplitude value from the maximum amplitude value as the amplitude of the extracted signal.

The determination unit 863 compares the amplitude of the extracted signal calculated by the amplitude extraction unit 862 with a preset amplitude value, and determines the leakage detection state based on the comparison result.

If the amplitude of the extracted signal is equal to or greater than the set amplitude value, the determination unit 863 determines that the operation of the leakage detecting device 7 is abnormal. On the other hand, if the amplitude of the extracted signal is smaller than the set amplitude value, the determination unit 863 determines that there is no abnormality in the operation of the electrical leakage detection device 7.

When determining that the operation of the electrical leakage detection device 7 is abnormal, the determination unit 863 outputs the 2 nd step-up voltage command to the step-up converter control unit 83 as a step-up voltage command. On the other hand, if the determination unit 863 determines that there is no abnormality in the operation of the electrical leakage detection device 7, it outputs the 1 st boosted voltage command to the boost converter control unit 83 as the boosted voltage command.

The determination unit 863 is configured to determine that the operation of the electrical leakage detection device 7 is abnormal if a condition that the amplitude of the extracted signal is equal to or greater than a set amplitude value is satisfied. As another example, the determination unit 863 may be further configured to determine that the operation of the electrical leakage detection device 7 is abnormal if a condition that the condition is satisfied continuously for a preset time, for example, for 1 second, in addition to the condition.

Here, when the rotation speed of the motor 3 varies, the rotation speed of the generator 2 varies, or the like, the 1 st boosted voltage command calculated by the 1 st boosted voltage command output unit 84 varies in accordance with the rotation speed variation. Further, the leakage detecting device 7 may erroneously detect leakage due to a variation in the 1 st boosted voltage command.

On the other hand, the leakage detection state determination unit 86 extracts a signal of a specific frequency band associated with a case where the leakage detection device 7 erroneously detects leakage from the 1 st boosted voltage command, and determines that the operation of the leakage detection device 7 is abnormal if the amplitude of the extracted signal is equal to or larger than the set amplitude value. When it is determined that the operation of the electrical leakage detection device 7 is abnormal, the electrical leakage detection state determination unit 86 outputs the 2 nd step-up voltage command, which does not cause the electrical leakage false detection, to the step-up converter control unit 83, and does not output the 1 st step-up voltage command, which may cause the electrical leakage false detection. With this configuration, occurrence of an operational abnormality of the leakage detecting device 7 can be suppressed.

Next, a series of operations of the control device 8 will be described with reference to fig. 5. Fig. 5 is a flowchart showing a series of operations of the control device 8 in embodiment 1 of the present invention. The flowchart shown in fig. 5 is repeatedly executed at a predetermined cycle, for example.

In step S101, the 1 st step-up voltage command output unit 84 calculates and outputs a 1 st step-up voltage command based on the motor torque command and the generator torque command input from the vehicle controller 9, the motor rotation speed input from the motor control unit 81, and the generator rotation speed input from the generator control unit 82, and the process proceeds to step S102.

In step S102, the frequency component extraction unit 861 performs band-pass filtering processing on the 1 st boosted voltage command output in step S101 to extract only a signal in a specific frequency band as an extraction signal, and the processing proceeds to step S103.

As the band pass filter, for example, a filter obtained by combining a primary low pass filter and a primary high pass filter may be used. The value of the boosted voltage command, which may cause erroneous detection of the leakage, is determined by performing on-board calculation, experiments, or the like, and the value of the specific frequency band is determined based on the value. Then, the setting value of the band pass filter is set in advance so that the signal of the specific frequency band can be extracted.

In step S103, the amplitude extraction unit 862 calculates the amplitude of the extracted signal extracted in step S102, and the process proceeds to step S104.

As described above, the amplitude extraction unit 862 extracts the maximum amplitude value and the minimum amplitude value of the signal in a set time period, for example, a period of 100ms, and calculates the amplitude of the extracted signal. The setting time can be appropriately changed according to the setting value of the band-pass filter. The setting time may be set to an integral multiple of the period of the frequency setting value of the band-pass filter.

In step S104, the determination unit 863 determines whether or not the amplitude of the extracted signal calculated in step S103 is equal to or greater than a set amplitude value. If the amplitude is equal to or larger than the set amplitude value, the determination unit 863 determines that the operation of the leak detection device 7 is abnormal, and the process proceeds to step S105. On the other hand, if the amplitude is smaller than the set amplitude value, the determination unit 863 determines that there is no abnormality in the operation of the electrical leakage detection device 7, and the process proceeds to step S107.

As is clear from the above-described steps S101 to S104, the electrical leakage detection state determination unit 86 extracts a signal of a specific frequency band as an extraction signal by performing band-pass filtering processing on the 1 st boosted voltage command output from the 1 st boosted voltage command output unit 84. The leakage detection state determination unit 86 calculates the amplitude of the extracted signal, and compares the calculated amplitude with a preset amplitude value to determine the leakage detection state.

In step S105, the 2 nd boosted voltage command output unit 85 outputs the preset 2 nd boosted voltage command, and the process proceeds to step S106.

In step S106, the determination unit 863 outputs the 2 nd boosted voltage command of the 1 st boosted voltage command output in step S101 and the 2 nd boosted voltage command output in step S105 as the boosted voltage command, and the process ends.

In step S107, the determination unit 863 determines whether or not the current step-up voltage command is the 2 nd step-up voltage command. That is, in step S107, it is determined which of the 2 nd boosted voltage command and the 1 st boosted voltage command is used as the boosted voltage command for controlling the boost converter 53 at the current time point.

In step S107, if it is determined that the current step-up voltage command is the 2 nd step-up voltage command, the process proceeds to step S108. On the other hand, if it is determined that the current step-up voltage command is not the 2 nd step-up voltage command, that is, the current step-up voltage command is the 1 st step-up voltage command, the process proceeds to step S109.

In step S108, the determination unit 863 outputs the 1 st boosted voltage command output in step S101 to the boost converter 53 as the boosted voltage command, and the process ends. In this case, since no abnormality occurs in the operation of the leakage detection device 7 even if the boost converter 53 is controlled in accordance with the 1 st boost voltage command, the determination unit 863 switches the boost voltage command output to the boost converter control unit 83 from the current 2 nd boost voltage command to the 1 st boost voltage command output in step S101. The boost converter control unit 83 controls the boost converter 53 in accordance with the 1 st boost voltage command after the switching.

In step S109, the determination unit 863 outputs the 1 st boosted voltage command output in step S101 to the boost converter 53 as the boosted voltage command, and the process ends. In this case, the determination unit 863 switches the boosted voltage command output to the boost converter control unit 83 from the current 1 st boosted voltage command to the 1 st boosted voltage command output in step S101. The boost converter control unit 83 controls the boost converter 53 in accordance with the 1 st boost voltage command after the switching.

As is clear from the above-described steps S105 to S109, when the electrical leakage detection state determination unit 86 determines that no abnormality has occurred in the operation of the electrical leakage detection device 7, it controls the boost converter 53 in accordance with the 1 st boost voltage command output by the 1 st boost voltage command output unit 84. When it is determined that the operation of the electrical leakage detection device 7 is abnormal, the electrical leakage detection state determination unit 86 controls the boost converter 53 in accordance with the 2 nd boost voltage command output from the 2 nd boost voltage command output unit 85.

In embodiment 1, the boosted voltage from the boost converter 53 is supplied to both the motor inverter 51 and the generator inverter 52, but the boosted voltage from the boost converter 53 may be supplied only to the motor inverter 51.

In the case of the above configuration, the 1 st step-up voltage command output unit 84 acquires the motor torque command and the motor rotation speed, and calculates and outputs the 1 st step-up voltage command based on the acquired motor torque command and the acquired motor rotation speed. Specifically, a map is prepared in advance in which the motor torque command and the motor rotation speed are associated with the boost voltage command so that the total loss of the motor 3 and the motor inverter 51 is minimized. Next, the 1 st boosted voltage command output unit 84 calculates a boosted voltage command corresponding to the acquired motor torque command and motor rotation speed from the map, and sets the boosted voltage command as the 1 st boosted voltage command.

In the case of the above configuration, the 2 nd step-up voltage command is set in advance to a value of the minimum step-up voltage required for the motor 3 to generate the maximum output of the motor 3.

As described above, according to embodiment 1, the band-pass filtering process is performed on the 1 st step-up voltage command calculated based on the motor torque command and the motor rotation speed or the 1 st step-up voltage command calculated based on the motor torque command, the motor rotation speed, the generator torque command, and the generator rotation speed, and the signal of the specific frequency band is extracted as the extraction signal. In this configuration, the amplitude of the extracted signal is calculated, and the calculated amplitude is compared with a preset amplitude value, thereby determining whether or not an abnormality has occurred in the operation of the leakage detecting device. This makes it possible to determine the operating state of the electrical leakage detection device provided in the electric vehicle.

In the above configuration, the output of the preset 2 nd step-up voltage command is performed in addition to the output of the 1 st step-up voltage command, and as a result of the determination of the electrical leakage detection state, the step-up converter is controlled based on the 1 st step-up voltage command when it is determined that the operation of the electrical leakage detection device is not abnormal, and the step-up converter is controlled based on the 2 nd step-up voltage command when it is determined that the operation of the electrical leakage detection device is abnormal.

Thus, even when the 1 st step-up voltage command calculated based on at least the motor torque command and the motor rotation speed periodically fluctuates due to fluctuation of the motor torque, fluctuation of the motor rotation speed, or the like caused by sudden accelerator depression, the 1 st step-up voltage command can be switched to the fixed value 2 nd step-up voltage command. As a result, in the electric vehicle, even if the leakage detection device falls into a state in which there is a possibility of erroneous detection of leakage, it is possible to suppress occurrence of erroneous detection of leakage and to minimize an increase in loss.

Embodiment 2.

Embodiment 2 of the present invention will explain a control device 8 including a 2 nd boosted voltage command output unit 85 having a configuration different from that of embodiment 1. In embodiment 2, the description of the same points as those in embodiment 1 described above is omitted, and the description is mainly focused on the differences from embodiment 1 described above.

Fig. 6 is a configuration diagram showing the control device 8 in embodiment 2 of the present invention. In fig. 6, the control device 8 includes a motor control unit 81, a generator control unit 82, a boost converter control unit 83, a 1 st boost voltage command output unit 84, a 2 nd boost voltage command output unit 85, and a leakage detection state determination unit 86. The 2 nd step-up voltage command output unit 85 receives the motor torque command and the generator torque command from the vehicle controller 9, the motor rotation speed from the motor control unit 81, and the generator rotation speed from the generator control unit 82.

In embodiment 1, the 2 nd boosted voltage command output unit 85 is configured to output a preset 2 nd boosted voltage command to the leakage current detection state determination unit 86. In contrast, in embodiment 2, the 2 nd boosted voltage command output unit 85 is configured to calculate the 2 nd boosted voltage command using a boosted voltage determination map described later, and output the calculated 2 nd boosted voltage command to the leakage current detection state determination unit 86.

Next, the 2 nd boosted voltage command output unit 85 will be further described with reference to fig. 7. Fig. 7 is a configuration diagram showing the 2 nd boosted voltage command output unit 85 in fig. 6. In fig. 7, the 2 nd step-up voltage command output unit 85 includes a motor-side voltage calculation unit 851, a generator-side voltage calculation unit 852, and a comparison unit 853.

The motor-side voltage calculation unit 851 calculates a motor-side voltage based on a motor torque command input from the vehicle controller 9 and a motor rotation speed input from the motor control unit 81.

Here, a method of calculating the motor-side voltage using the motor torque command and the motor rotation speed is as follows.

That is, a voltage-boosting determination map is prepared in advance, which is associated with the motor rotation speed and the motor torque command and is divided into a voltage-boosting region in which the voltage-boosting converter 53 is in a voltage-boosting state and a non-voltage-boosting region in which the voltage-boosting converter 53 is in a non-voltage-boosting state. The boost state is a state in which the boost voltage of the boost converter 53 is a predetermined value required to generate the maximum output of the motor 3. The non-boosted state is a state in which the boosted voltage of the boost converter 53 becomes the value of the battery voltage.

The total loss of the motor 3 and the motor inverter 51 in the non-boosted state and the total loss of the motor 3 and the motor inverter 51 in the boosted state are previously known for each value of the motor rotation speed and the motor torque command. The boost determination map is generated such that, of these total losses, the motor speed and the motor torque command for which the total loss in the non-boost state is low are included in the non-boost region, and the motor speed and the motor torque command for which the total loss in the boost state is low are included in the boost region.

The motor-side voltage calculation unit 851 confirms, using the boost determination map, which of the non-boost region and the boost region the point formed by the motor torque command input from the vehicle controller 9 and the motor rotation speed input from the motor control unit 81 includes.

If this point is included in the boosted voltage region in the boosted voltage determination map, the motor-side voltage calculation unit 851 outputs a value of a preset minimum boosted voltage required to generate the maximum output of the motor 3 to the comparison unit 853 as the motor-side voltage. On the other hand, if the point is included in the non-boosted voltage region in the boosting determination map, the motor-side voltage calculation unit 851 outputs the value of the battery voltage to the comparison unit 853 as the motor-side voltage. When the value of the battery voltage output as the motor-side voltage is the 2 nd step-up voltage command, the step-up converter 53 does not perform the step-up operation, and supplies the voltage of the battery 6 to the motor inverter 51 and the generator inverter 52 as it is.

Further, since the boost-non-boost boundary changes when the battery voltage changes, a boost determination map corresponding to the battery voltage may be prepared in advance.

Thus, the 2 nd boosted voltage command output unit 85 acquires the motor torque command and the motor rotation speed, and calculates the motor-side voltage based on the acquired motor torque command and the motor rotation speed using the boosted voltage determination map.

The generator-side voltage calculation unit 852 calculates a generator-side voltage based on the generator torque command input from the vehicle controller 9 and the generator rotation speed input from the generator control unit 82.

The method of calculating the generator-side voltage using the generator torque command and the generator rotation speed is the same as the method of calculating the motor-side voltage described above.

That is, as the same boost determination map as described above, a boost determination map is prepared in advance which is associated with the generator speed and the generator torque command and is divided into a boost region in which the boost converter 53 is in the boost state and a non-boost region in which the boost converter 53 is in the non-boost state. The boost state is a state in which the boost voltage of the boost converter 53 is a predetermined value required to generate the maximum output of the generator 2. The non-boosted state is a state in which the boosted voltage of the boost converter 53 becomes the value of the battery voltage.

The total loss of the generator 2 and the generator inverter 52 in the non-boosted state and the total loss of the generator 2 and the generator inverter 52 in the boosted state are previously known for each value of the generator rotation speed and the generator torque command. The boost determination map is generated such that, of these total losses, the generator speed and the generator torque command for which the total loss in the non-boost state is low are included in the non-boost region, and the generator speed and the generator torque command for which the total loss in the boost state is low are included in the boost region.

The generator-side voltage calculation unit 852 uses the boost determination map to determine which of the non-boost region and the boost region the point formed by the generator torque command input from the vehicle controller 9 and the generator rotation speed input from the generator control unit 82 is included in.

If the point is included in the boost determination map in the boost region, the generator-side voltage calculation unit 852 outputs the value of the preset minimum boost voltage required to generate the maximum output of the generator 2 to the comparison unit 853 as the generator-side voltage. On the other hand, if the point is included in the non-boosted voltage region in the boosting determination map, the generator-side voltage calculation unit 852 outputs the value of the battery voltage to the comparison unit 853 as the generator-side voltage. When the value of the battery voltage output as the generator-side voltage is the 2 nd step-up voltage command, the step-up converter 53 does not perform the step-up operation, and supplies the voltage of the battery 6 to the motor inverter 51 and the generator inverter 52 as it is.

Thus, the 2 nd boosted voltage command output unit 85 acquires the generator torque command and the generator rotation speed, and calculates the generator-side voltage based on the acquired generator torque command and the generator rotation speed using the boosted voltage determination map.

The comparing unit 853 outputs the larger one of the motor-side voltage input from the motor-side voltage computing unit 851 and the generator-side voltage input from the generator-side voltage computing unit 852 to the leakage detection state determining unit 86 as the 2 nd step-up voltage command.

In embodiment 2, the boosted voltage from the boost converter 53 is supplied to both the motor inverter 51 and the generator inverter 52, but the boosted voltage from the boost converter 53 may be supplied only to the motor inverter 51.

In the case of the above configuration, the 2 nd boosted voltage command output unit 85 acquires the motor torque command and the motor rotation speed, calculates the motor-side voltage based on the acquired motor torque command and the motor rotation speed using the above-described boosted voltage determination map, and outputs the calculated motor-side voltage as the 2 nd boosted voltage command.

As described above, according to embodiment 2, in contrast to the configuration of embodiment 1, the configuration is configured such that the 2 nd step-up voltage command obtained by using the step-up determination map based on the motor torque command and the motor rotation speed, or based on the motor torque command, the motor rotation speed, the generator torque command, and the generator rotation speed is output without outputting the preset 2 nd step-up voltage command.

In the above configuration, as a result of the determination of the leakage detection state, the step-up converter is controlled based on the 1 st step-up voltage command when it is determined that there is no abnormality in the operation of the leakage detection device, and the step-up converter is controlled based on the 2 nd step-up voltage command when it is determined that there is an abnormality in the operation of the leakage detection device.

Thus, in the electrically powered vehicle, even if the leakage detection device falls into a state in which there is a possibility that the leakage is erroneously detected, it is possible to suppress the variation in the boosted voltage command that causes the erroneous detection of the leakage. Further, since the 2 nd boost voltage command used when controlling the boost converter can be selected to be the side with less loss in the non-boost region and the boost region in the boost determination map, efficient operation can be performed.

Embodiment 3.

In embodiment 3 of the present invention, a control device 8 having a configuration different from those of embodiments 1 and 2 will be described. In embodiment 3, the same points as those in embodiments 1 and 2 are not described, and differences from embodiments 1 and 2 described above will be mainly described.

Fig. 8 is a configuration diagram showing a control device 8 according to embodiment 3 of the present invention. In fig. 8, control device 8 includes a motor control unit 81, a generator control unit 82, a boost converter control unit 83, a 1 st boost voltage command output unit 84, and a leakage detection state determination unit 86.

The 1 st boosted voltage command output unit 84 calculates a 1 st boosted voltage command based on the motor torque command and the generator torque command input from the vehicle controller 9, the motor rotation speed input from the motor control unit 81, and the generator rotation speed input from the generator control unit 82, and outputs the 1 st boosted voltage command to the boost converter control unit 83.

The boost converter control unit 83 controls the boost converter 53 so that the boosted voltage of the boost converter 53 becomes the 1 st boosted voltage command input from the 1 st boosted voltage command output unit 84.

The leakage detection state determination unit 86 in embodiment 3 has the functions of the frequency component extraction unit 861 and the amplitude extraction unit 862 and a part of the function of the determination unit 863 described in embodiment 1.

That is, the leakage detection state determination unit 86 performs the band-pass filtering process on the 1 st boosted voltage command input from the 1 st boosted voltage command output unit 84, and extracts only the signal of the specific frequency band as the extraction signal. Then, the electric leakage detection state determination unit 86 calculates the amplitude of the extracted signal.

The leakage detection state determination unit 86 compares the amplitude of the calculated extraction signal with a preset amplitude value, and determines the leakage detection state based on the comparison result. When the amplitude of the extracted signal is equal to or larger than the set amplitude value, the leakage detection state determination unit 86 determines that the operation of the leakage detection device 7 is abnormal. On the other hand, if the amplitude of the extracted signal is smaller than the set amplitude value, the leakage detection state determination unit 86 determines that there is no abnormality in the operation of the leakage detection device 7.

If it is determined that the operation of the electrical leakage detection device 7 is abnormal, the electrical leakage detection state determination unit 86 performs control so as to stop the operation of the electrical leakage detection device 7. On the other hand, if the electrical leakage detection state determination unit 86 determines that there is no abnormality in the operation of the electrical leakage detection device 7, the operation of the electrical leakage detection device 7 is continued.

As described above, according to embodiment 3, the operation of the electrical leakage detection device is stopped when it is determined that an abnormality has occurred in the operation of the electrical leakage detection device as a result of the determination of the electrical leakage detection state. Thus, in the electrically powered vehicle, when the leakage detecting device falls into a state in which there is a possibility that the leakage detecting device erroneously detects a leakage, the operation of the leakage detecting device is stopped, so that occurrence of erroneous detection of a leakage can be suppressed, and as a result, an increase in loss can be suppressed.

While embodiments 1 to 3 have been described individually, the configuration examples disclosed in each of embodiments 1 to 3 can be arbitrarily combined.

In embodiments 1 and 2, the following cases are exemplified: the determination of the leak detection state by the leak detection state determination unit 86 is applied to control for switching the step-up voltage command of the step-up converter 53 to the 1 st step-up voltage command and the 2 nd step-up voltage command. In embodiment 3, the following case is exemplified: the electric leakage detection state determination is applied to control for stopping the operation of the electric leakage detection device. However, the application examples of the electrical leakage detection state determination are not limited to these examples, and for example, the electrical leakage detection state determination may be applied to other controls than the above-described control, or the electrical leakage detection state determination may be applied to monitoring of the operation state of the electrical leakage detection device.

Description of the reference symbols

1 Engine

2 electric generator

3 electric motor

4 tyre

5 power drive unit

6 cell

7 electric leakage detection device

8 control device

9 vehicle controller

Inverter for 51 motor

Inverter for 52 generator

53 boost converter

81 Motor control Unit

82 generator control part

83 boost converter control unit

84 1 st boosted voltage command output unit

85 nd 2 nd boost voltage command output unit

86 leakage detection state determination unit

851 Motor side Voltage operation section

852 generator side voltage computing unit

853 comparing unit

861 frequency component extracting unit

862 amplitude extracting part

863 judging part

Claims

1. A control device for an electrically powered vehicle that determines an operating state of a leakage detection device provided in an electrically powered vehicle that includes an electric motor and a power drive unit that drives the electric motor, the control device for an electrically powered vehicle being characterized in that,

the power driving unit includes:

a motor inverter that drives the motor by being controlled by a motor torque command for controlling the motor; and

a step-up converter that steps up a voltage supplied from a DC power supply by being controlled by a 1 st step-up voltage command and supplies the stepped-up voltage to the motor inverter as a step-up voltage,

the control device includes:

a 1 st step-up voltage command output unit that acquires the motor torque command and a motor rotation speed of the motor, calculates the 1 st step-up voltage command based on the acquired motor torque command and the acquired motor rotation speed, and outputs the 1 st step-up voltage command; and

and a leakage detection state determination unit that performs a band-pass filtering process on the 1 st boosted voltage command output by the 1 st boosted voltage command output unit to extract a signal of a specific frequency band as an extraction signal, calculates an amplitude of the extraction signal, and compares the calculated amplitude with a preset amplitude value to determine whether or not the leakage detection device has an abnormal operation.

2. The control device of an electric vehicle according to claim 1,

the step-up converter performs the step-up by controlling the step-up converter in accordance with a 2 nd step-up voltage command in addition to the 1 st step-up voltage command,

the control device further includes a 2 nd step-up voltage command output unit that outputs the 2 nd step-up voltage command set in advance,

the leakage detection state determination unit is configured to:

controlling the boost converter in accordance with the 1 st boosted voltage command output from the 1 st boosted voltage command output unit when it is determined that the operation abnormality has not occurred,

and controlling the boost converter in accordance with the 2 nd boosted voltage command output from the 2 nd boosted voltage command output unit when it is determined that the operation abnormality has occurred.

3. The control device of an electric vehicle according to claim 2,

the value of the 2 nd step-up voltage command is set so that the value of the 2 nd step-up voltage command becomes the value of the minimum step-up voltage required for the motor to generate the maximum output of the motor.

4. The control device of an electric vehicle according to claim 1,

the control device further includes a 2 nd boosted voltage command output unit that outputs the 2 nd boosted voltage command,

the 2 nd step-up voltage command output unit is configured to:

acquiring the motor torque command and the motor rotation speed, calculating a motor-side voltage based on the acquired motor torque command and the motor rotation speed using a boost determination map associated with the motor rotation speed and the motor torque command and divided into a boost region in which the boost converter is in a boost state and a non-boost region in which the boost converter is in a non-boost state, and outputting the calculated motor-side voltage as the 2 nd boost voltage command,

the leakage detection state determination unit is configured to:

5. The control device of an electric vehicle according to claim 1,

the leakage detection state determination unit stops the operation of the leakage detection device when determining that the operation abnormality has occurred.

6. The control device of an electric vehicle according to claim 1,

the electric vehicle further includes a generator that generates electricity,

the power drive unit further includes a generator inverter controlled by a generator torque command for controlling the generator to thereby drive the generator,

the boost converter further supplies the boosted voltage to the inverter for the generator,

the 1 st boosted voltage command output unit is configured to:

the generator torque command and the generator rotational speed of the generator are also acquired, and the 1 st step-up voltage command is calculated and output based on the acquired generator torque command and the acquired generator rotational speed on the basis of the acquired motor torque command and the acquired generator rotational speed.

7. The control device of an electric vehicle according to claim 6,

the leakage detection state determination unit is configured to:

8. The control device of an electric vehicle according to claim 7,

the value of the 2 nd step-up voltage command is set such that the value of the 2 nd step-up voltage command is the larger of the minimum step-up voltage required to cause the motor to generate the maximum output of the motor and the minimum step-up voltage required to cause the generator to generate the maximum output of the generator.

9. The control device of an electric vehicle according to claim 6,

the 2 nd step-up voltage command output unit is configured to:

acquiring the motor torque command and the motor rotation speed, calculating a motor-side voltage based on the acquired motor torque command and the motor rotation speed using a boost determination map associated with the motor rotation speed and the motor torque command and divided into a boost region in which the boost converter is in a boost state and a non-boost region in which the boost converter is in a non-boost state,

acquiring the generator torque command and the generator rotational speed, calculating a generator-side voltage based on the acquired generator torque command and the generator rotational speed using a boost determination map associated with the generator rotational speed and the generator torque command and divided into a boost region in which the boost converter is in a boost state and a non-boost region in which the boost converter is in a non-boost state,

and outputting the larger one of the calculated motor-side voltage and generator-side voltage as the 2 nd step-up voltage command.

10. The control device of an electric vehicle according to claim 6,

11. A method of determining a state of leakage detection of an electric vehicle, the method being a method of determining an operating state of a leakage detection device provided in the electric vehicle including a motor and a power drive unit that drives the motor, the method being characterized in that the method includes the step of determining the operating state of the leakage detection device,

the power driving unit includes:

the electric leakage detection state judgment method for an electric vehicle includes:

acquiring the motor torque command and a motor rotation speed of the motor, and calculating the 1 st step-up voltage command based on the acquired motor torque command and the acquired motor rotation speed; and

and a step of performing a band-pass filtering process on the calculated 1 st step-up voltage command to extract a signal of a specific frequency band as an extraction signal, calculating an amplitude of the extraction signal, and comparing the calculated amplitude with a preset amplitude value to determine whether or not the leakage detecting device has an abnormal operation.