WO2019186762A1

WO2019186762A1 - Drive device, electric vehicle, and drive device control method

Info

Publication number: WO2019186762A1
Application number: PCT/JP2018/012750
Authority: WO
Inventors: 一由希目黒; 雄大井ノ口
Original assignee: 新電元工業株式会社
Priority date: 2018-03-28
Filing date: 2018-03-28
Publication date: 2019-10-03
Also published as: TW202005256A; TWI732199B; CN111886796A; CN111886796B; JP7083891B2; JPWO2019186762A1

Abstract

A main control circuit of this drive device detects the first charged voltage of a smoothing capacitor before the start of discharging through a discharging resistor. Before a preset set time elapses from the start of discharging through the discharging resistor, the main control circuit calculates, by multiplying the first charged voltage by a preset factor, a discharging continuable voltage that is the charged voltage of the smoothing capacitor estimated during the elapse of the set time and capable of being continuously discharged through the discharging resistor. The main control circuit detects the second charged voltage of the smoothing capacitor during the elapse of the set time and compares the second charged voltage with the discharging continuable voltage. When the second charged voltage is less than or equal to the discharging continuable voltage, the main control circuit controls a discharging control circuit so as to continue discharging through the discharging resistor. Meanwhile, when the second charged voltage is greater than the discharging continuable voltage, the main control circuit controls the discharging control circuit so as to stop discharging through the discharging resistor.

Description

Drive device, electric vehicle, and control method of drive device

The present invention relates to a drive device, an electric vehicle, and a drive device control method.

An electric motorcycle using a battery as a power source and a three-phase motor (hereinafter referred to as a motor) as a power source is known.

In this type of electric motorcycle, in order to drive the motor, a three-phase full bridge circuit (that is, an inverter circuit) having a high-side switch and a low-side switch for each phase is used to drive the motor to each phase coil of the motor. The energization was controlled.

Also, a smoothing capacitor was provided between the battery and the three-phase bullbridge circuit.

In order to discharge the charging voltage of the smoothing capacitor, discharging using a discharge resistor has been conventionally performed.

However, when a large voltage is applied to the discharge resistor while the battery is connected to the smoothing capacitor, there has been a problem that the amount of heat generated by the discharge resistor becomes excessive.

Here, Japanese Unexamined Patent Application Publication No. 2013-38895 discloses a capacitor discharge circuit. However, in Japanese Patent Laid-Open No. 2013-38895, a high-resistance parallel connection body is connected between the input terminals of the inverter in order to ensure a discharge path even when an abnormality occurs in the resistor of the discharge circuit. Therefore, there is a problem that the discharge resistance increases.

Accordingly, the present invention provides a drive device, an electric vehicle, and a drive device manufacturing method that can prevent the amount of heat generated by the discharge resistor from becoming excessive and can reduce the size of the discharge resistor. Objective.

A driving device according to one embodiment of the present invention includes:
A smoothing connected between a power supply terminal connected to the positive electrode of the battery and a ground terminal connected to the negative electrode of the battery, and charged with a voltage supplied from the battery between the power supply terminal and the grounding terminal. A capacitor,
Between the power supply terminal and the ground terminal, connected in parallel with the smoothing capacitor, a discharge resistor for discharging the smoothing capacitor,
A discharge control circuit that is connected in series with the discharge resistor between the power supply terminal and the ground terminal, and controls discharge of the smoothing capacitor by the discharge resistor;
A main control circuit for controlling the operation of the discharge control circuit;
A drive circuit for driving the motor by supplying an AC voltage obtained by converting the DC voltage between the power supply terminal and the ground terminal to the motor; and
The main control circuit includes:
Detecting the first charging voltage of the smoothing capacitor between the power supply terminal and the ground terminal before starting discharge by the discharge resistor;
The discharge due to the discharge resistance predicted when the set time elapses by multiplying the first charging voltage and the preset coefficient before the preset set time elapses from the start of the discharge due to the discharge resistance. A discharge continuation possible voltage which is a charging voltage of the smoothing capacitor capable of continuation of
Detecting a second charging voltage of the smoothing capacitor between the power supply terminal and the ground terminal when the set time elapses;
Comparing the second charge voltage and the sustainable voltage;
When the second charge voltage is equal to or lower than the discharge continuable voltage, the discharge control circuit is controlled to continue the discharge by the discharge resistance, while the second charge voltage is higher than the discharge continuable voltage. If it is too large, the discharge control circuit is controlled to stop the discharge by the discharge resistance.

In the driving device,
The main control circuit includes:
When the second charging voltage is equal to or lower than the discharge continuation possible voltage, the smoothing capacitor is discharged by the discharge resistor until the charging voltage of the smoothing capacitor becomes equal to or lower than a third charging voltage smaller than the second charging voltage. The discharge control circuit may be controlled so as to continue.

In the driving device,
The main control circuit includes:
When the second charging voltage is equal to or lower than the discharge continuation possible voltage, the discharge control circuit is controlled to maintain the connection of the discharge resistor to the smoothing capacitor, while the second charging voltage is When the voltage is higher than the discharge continuable voltage, the discharge control circuit may be controlled so as to cut off the discharge resistance from the smoothing capacitor.

In the driving device,
The main control circuit includes:
The discharge continuation possible voltage may be calculated before the start of discharge by the discharge resistance.

In the driving device,
The coefficient may be set so as to correlate with a minimum value of the discharge amount of the smoothing capacitor predicted when the set time elapses.

In the driving device,
The coefficient is set to change according to the elapsed time from the start of the discharge,
The main control circuit includes:
The discharge continuable voltage may be calculated by multiplying the first charging voltage by a coefficient when the elapsed time is the set time.

In the driving device,
The main control circuit monitors an integrated value of the first charging voltage and the coefficient for each cycle at a cycle shorter than the set time from the start of discharge by the discharge resistor, and the discharge control circuit based on a monitoring result May be controlled.

In the driving device,
The main control circuit includes:
By multiplying the first charging voltage by the second coefficient set so as to correlate with the maximum value of the discharge amount of the smoothing capacitor predicted when the set time elapses, the prediction is made when the set time elapses. Calculating a lower limit charging voltage of the smoothing capacitor,
When the second charging voltage is equal to or higher than the lower limit charging voltage, the discharge control circuit may be controlled to continue discharging by the discharge resistance.

In the driving device,
The main control circuit may further control the operation of the drive circuit.

In the driving device,
The main control circuit includes:
When the discharge control circuit is controlled so as to stop the discharge of the smoothing capacitor by the discharge resistor, the discharge of the smoothing capacitor by the motor may be controlled by controlling the drive circuit.

In the driving device,
The drive circuit is
A first transistor having one end connected to the power supply terminal and the other end connected to a first output terminal of a first phase;
A second transistor having one end connected to the power supply terminal and the other end connected to a second output terminal of the second phase;
A third transistor having one end connected to the power supply terminal and the other end connected to a third phase third output terminal;
A fourth transistor having one end connected to the first output terminal and the other end connected to the ground terminal;
A fifth transistor having one end connected to the second output terminal and the other end connected to the ground terminal;
A sixth transistor having one end connected to the third output terminal and the other end connected to the ground terminal;
The main control circuit includes:
The discharge of the smoothing capacitor by the motor may be controlled by controlling the first to sixth transistors.

In the driving device,
When the smoothing capacitor is connected to the battery, the main control circuit detects the first charging voltage, calculates the discharge continuable voltage, detects the second charging voltage, and the second charging voltage. And the discharge control circuit may be controlled in accordance with a comparison result between the discharge sustainable voltage and the discharge continuable voltage.

In the driving device,
The discharge control circuit includes:
Detecting the first charging voltage and the second charging voltage, and outputting information on the first and second charging voltages to the main control circuit;
The main control circuit includes:
The first and second charging voltages may be detected by inputting the information.

An electric vehicle according to an aspect of the present invention includes:
An electric vehicle including a battery, a motor, and a drive device,
The driving device includes:
Connected between a power supply terminal connected to the positive electrode of the battery and a ground terminal connected to the negative electrode of the battery, and charged with a voltage supplied from the battery between the power supply terminal and the ground terminal. A smoothing capacitor;
Between the power supply terminal and the ground terminal, connected in parallel with the smoothing capacitor, a discharge resistor for discharging the smoothing capacitor,
A discharge control circuit that is connected in series with the discharge resistor between the power supply terminal and the ground terminal, and controls discharge of the smoothing capacitor by the discharge resistor;
A main control circuit for controlling the operation of the discharge control circuit;
A drive circuit for driving the motor by supplying an AC voltage obtained by converting a DC voltage between the power supply terminal and the ground terminal to the motor; and
The main control circuit includes:
Detecting the first charging voltage of the smoothing capacitor before starting discharge by the discharge resistor;
The discharge due to the discharge resistance predicted when the set time elapses by multiplying the first charging voltage and the preset coefficient before the preset set time elapses from the start of the discharge due to the discharge resistance. A discharge continuation possible voltage which is a charging voltage of the smoothing capacitor capable of continuation of
Detecting a second charging voltage of the smoothing capacitor when the set time elapses;
Comparing the second charge voltage and the sustainable voltage;
When the second charge voltage is equal to or lower than the discharge continuable voltage, the discharge control circuit is controlled to continue the discharge by the discharge resistance, while the second charge voltage is higher than the discharge continuable voltage. If it is too large, the discharge control circuit is controlled to stop the discharge by the discharge resistance.

A control method of a driving device according to an aspect of the present invention includes:
A smoothing connected between a power supply terminal connected to the positive electrode of the battery and a ground terminal connected to the negative electrode of the battery, and charged with a voltage supplied from the battery between the power supply terminal and the grounding terminal. A capacitor,
Between the power supply terminal and the ground terminal, connected in parallel with the smoothing capacitor, a discharge resistor for discharging the smoothing capacitor,
A discharge control circuit that is connected in series with the discharge resistor between the power supply terminal and the ground terminal, and controls discharge of the smoothing capacitor by the discharge resistor;
A drive circuit that supplies an AC voltage obtained by converting a DC voltage between the power supply terminal and the ground terminal to a motor and drives the motor,
Detecting the first charging voltage of the smoothing capacitor before starting discharge by the discharge resistor;
The discharge due to the discharge resistance predicted when the set time elapses by multiplying the first charging voltage and the preset coefficient before the preset set time elapses from the start of the discharge due to the discharge resistance. A discharge continuation possible voltage which is a charging voltage of the smoothing capacitor capable of continuation of
Detecting a second charging voltage of the smoothing capacitor when the set time elapses;
Comparing the second charge voltage and the sustainable voltage;
When the second charge voltage is equal to or lower than the discharge continuable voltage, the discharge control circuit is controlled to continue the discharge by the discharge resistance, while the second charge voltage is higher than the discharge continuable voltage. If it is too large, the discharge control circuit is controlled to stop the discharge by the discharge resistance.

A drive device according to one embodiment of the present invention is connected between a power supply terminal connected to the positive electrode of the battery and a ground terminal connected to the negative electrode of the battery, and is supplied from the battery between the power supply terminal and the ground terminal. Between the power supply terminal and the ground terminal, and between the power supply terminal and the ground terminal, and between the power supply terminal and the ground terminal. A power control is performed on the DC voltage between the power supply terminal and the ground terminal, connected to the resistor in series and controlling the discharge of the smoothing capacitor by the discharge resistor, the main control circuit controlling the operation of the discharge control circuit, and A drive circuit for driving the motor by supplying an AC voltage to the motor, and the main control circuit performs the first charging of the smoothing capacitor between the power supply terminal and the ground terminal before the discharge by the discharge resistor is started. By detecting the voltage and multiplying the first charging voltage by a preset coefficient before the preset set time elapses from the start of discharge by the discharge resistor, the discharge resistance is predicted when the preset time elapses. A discharge continuable voltage, which is a charge voltage of a smoothing capacitor capable of continuing discharge, is calculated, and a second charge voltage of the smoothing capacitor between the power supply terminal and the ground terminal is detected when the set time has elapsed, and the second charge is performed. When the second charge voltage is equal to or lower than the discharge continuable voltage, the discharge control circuit is controlled to continue the discharge by the discharge resistor, while the second charge voltage is When the voltage is higher than the discharge continuable voltage, the discharge control circuit is controlled to stop the discharge by the discharge resistance.

Thereby, according to the drive device of the present invention, it is possible to prevent the amount of heat generated by the discharge resistor from becoming excessive and to reduce the size of the discharge resistor.

FIG. 1 is a diagram illustrating an example of a configuration of an electric vehicle control device 100 according to the first embodiment. FIG. 2 is a flowchart illustrating an operation example of the electric vehicle control device 100 according to the first embodiment. FIG. 3 is a charging voltage graph showing an operation example of the electric vehicle control apparatus 100 according to the first embodiment. FIG. 4 is a diagram illustrating an example of the configuration of the electric vehicle control device 100 according to the second embodiment.

Embodiments according to the present invention will be described below with reference to the drawings. In addition, embodiment shown below does not limit this invention. In the drawings referred to in the embodiments, the same portions or portions having similar functions are denoted by the same or similar reference numerals, and the repeated description thereof is omitted.

(First embodiment)
First, an electric vehicle control apparatus 100 according to a first embodiment as an example of a drive apparatus will be described with reference to FIGS. 1 to 3.

FIG. 1 is a diagram illustrating an example of a configuration of an electric vehicle control device 100 according to the first embodiment.

For example, as shown in FIG. 1, the electric vehicle control device 100 according to the first embodiment generates drive voltages MU, MV, and MW from the voltage of the battery B, and the drive voltages MU, MV, and MW. Thus, the motor M is driven.

The electric vehicle control apparatus 100 converts the back electromotive voltage output from the motor M into a DC regenerative voltage during regeneration by the motor M, and supplies the DC regenerative voltage between the power supply terminal TB and the ground terminal TG to supply the battery BH. May be charged.

For example, as shown in FIG. 1, the electric vehicle control apparatus 100 includes a power supply terminal TB, a ground terminal TG, a smoothing capacitor FC, a discharge resistor FR, a discharge control circuit FX, a drive circuit Z, And a control circuit CON.

In addition, the motor M drives a wheel of an electric motorcycle, for example.

Further, the electric vehicle control device 100, the battery B, and the switch SW are mounted on, for example, the above-described electric motorcycle.

Further, for example, as shown in FIG. 1, the positive terminal of the battery B is connected to the power supply terminal TB via the switch SW.

The ground terminal TG is connected to the negative electrode of the battery B as shown in FIG.

The switch SW has one end connected to the positive electrode of the battery B and the other end connected to the power supply terminal TB. When the switch SW is turned on, the switch SW is electrically connected between the positive electrode of the battery B and the power supply terminal TB. On the other hand, when the switch SW is turned off, the positive electrode of the battery B and the power supply terminal TB are electrically disconnected.

The switch SW is controlled to be turned on or off by the main control circuit CON as will be described later.

The smoothing capacitor FC is connected between the power supply terminal TB and the ground terminal TG. The smoothing capacitor FC is charged with a voltage supplied between the power supply terminal TB and the ground terminal TG.

For example, as shown in FIG. 1, the smoothing capacitor FC is charged with the voltage output from the battery B. The smoothing capacitor FC may be charged with regenerative power output from the drive circuit Z.

Further, for example, as shown in FIG. 1, the discharge resistor FR is connected in parallel with the smoothing capacitor FC between the power supply terminal TB and the ground terminal TG. This discharge resistor FR is for discharging the smoothing capacitor FC. The discharge resistor FR is, for example, a single resistor disposed so as to fit in the constrained space of the electric vehicle control device 100.

Further, the discharge control circuit FX is connected in series with the discharge resistor FR between the power supply terminal TB and the ground terminal TG, for example, as shown in FIG.

For example, in the example of FIG. 1, one end of the discharge resistor FR is connected to the power supply terminal TB. The discharge control circuit FX has one end connected to the other end of the discharge resistor FR and the other end connected to the ground terminal TG.

The discharge control circuit FX controls the discharge of the smoothing capacitor FC by the discharge resistor FR.

For example, the discharge control circuit FX is configured to discharge the smoothing capacitor FC by conducting (that is, turning on) between the other end of the discharge resistor FR and the ground terminal TG (the other end of the smoothing capacitor FC). .

On the other hand, when the smoothing capacitor FC is charged, the discharge control circuit FX blocks (that is, turns off) between the other end of the discharge resistor FR and the ground terminal TG (the other end of the smoothing capacitor FC). It is like that.

The discharge control circuit FX may be operated by a voltage between the power supply terminal TB and the ground terminal TG (charging voltage of the smoothing capacitor FC). For example, the discharge control circuit FX may be activated when the voltage between the power supply terminal TB and the ground terminal TG (the charging voltage VFC of the smoothing capacitor FC) is equal to or higher than a predetermined value.

In addition, as shown in FIG. 1, for example, the drive circuit Z generates three-phase AC voltages MU, MV, and MW obtained by converting the DC voltage between the power supply terminal TB and the ground terminal TG when the motor M is driven. The motor M is driven by being supplied to the motor M via the first output terminal TU, the second output terminal TV, and the third output terminal TW.

On the other hand, the drive circuit Z generates a back electromotive voltage (supplied via the first output terminal TU, the second output terminal TV, and the third output terminal TW) output from the motor M during regeneration by the motor M. It may be converted into a DC regenerative voltage and supplied between the power supply terminal TB and the ground terminal TG. That is, the drive circuit Z may be configured to return (charge) the regenerative power supplied from the motor M to the battery B and the smoothing capacitor FC.

When the switch SW is turned on (when not in the cutoff state described later), the battery B is also charged with the regenerative power, and the rise of the charging voltage VFC of the smoothing capacitor FC is moderated. .

Here, for example, as shown in FIG. 1, the drive circuit Z includes a first output terminal TU, a second output terminal TV, a third output terminal TW, a first transistor Q1, and a second transistor Q2. The third transistor Q3, the fourth transistor Q4, the fifth transistor Q5, the sixth transistor Q6, the first diode D1, the second diode D2, the third diode D3, the fourth diode D4, 5 diode D5 and 6th diode D6.

The first output terminal TU is connected to a U-phase coil (not shown) of the motor M.

The second output terminal TV is connected to a V-phase coil (not shown) of the motor M.

The third output terminal TW is connected to a W-phase coil (not shown) of the motor M.

For example, as shown in FIG. 1, the first transistor Q1 has one end (drain) connected to the power supply terminal TB and the other end (source) connected to the first output terminal TU of the first phase (U phase). Has been. The first transistor Q1 is an nMOS transistor in the example of FIG.

The first diode D1 has a cathode connected to the power supply terminal TB and an anode connected to the first output terminal TU.

The second transistor Q2 has one end (drain) connected to the power supply terminal TB and the other end (source) connected to the second output terminal TV of the second phase (V phase). The second transistor Q2 is an nMOS transistor in the example of FIG.

The second diode D2 has a cathode connected to the power supply terminal TB and an anode connected to the second output terminal TV.

The third transistor Q3 has one end (drain) connected to the power supply terminal TB and the other end (source) connected to the third output terminal TW of the third phase (W phase). The third transistor Q3 is an nMOS transistor in the example of FIG.

The third diode D3 has a cathode connected to the power supply terminal TB and an anode connected to the third output terminal TW.

The fourth transistor Q4 has one end (drain) connected to the first output terminal TU and the other end (source) connected to the ground terminal TG. The fourth transistor Q4 is an nMOS transistor in the example of FIG.

The fourth diode D4 has a cathode connected to the first output terminal TU and a cathode connected to the ground terminal TG.
The fifth transistor Q5 has one end (source) connected to the second output terminal TV and the other end (drain) connected to the ground terminal TG. The fifth transistor Q5 is an nMOS transistor in the example of FIG.

The fifth diode D5 has a cathode connected to the second output terminal TV and an anode connected to the ground terminal TG.

The sixth transistor Q6 has one end (source) connected to the third output terminal TW and the other end (drain) connected to the ground terminal TG. The sixth transistor Q6 is an nMOS transistor in the example of FIG.

The sixth diode D6 has a cathode connected to the third output terminal TW and an anode connected to the ground terminal TG.

The first to sixth transistors Q1 to Q6 have a predetermined pattern when a gate control signal (gate voltage) output from the main control circuit CON is supplied to the gates of the first to sixth transistors Q1 to Q6. It is supposed to work.

The main control circuit CON turns off the switch SW when the battery B is fully charged, and turns on the switch SW when the voltage of the battery B becomes less than a predetermined value.

The main control circuit CON controls the operation of the discharge control circuit FX.

The main control circuit CON detects the first charging voltage of the smoothing capacitor FC between the power supply terminal TB and the ground terminal TG before the discharge by the discharge resistor FR is started.

After detecting the first charging voltage, the main control circuit CON multiplies the detected first charging voltage and a preset coefficient before the preset time elapses from the start of discharge by the discharge resistor FR. Thus, a discharge continuable voltage, which is a charging voltage of the smoothing capacitor FC capable of continuing the discharge by the discharge resistor FR predicted when the set time has elapsed, is calculated.

When the set time has elapsed, the main control circuit CON detects the second charging voltage of the smoothing capacitor FC between the power supply terminal TB and the ground terminal TG.

After detecting the second charging voltage, the main control circuit CON compares the detected second charging voltage with the calculated discharge continuation possible voltage.

When the second charging voltage is equal to or lower than the discharge continuation possible voltage, the main control circuit CON controls the discharge control circuit FX so as to continue the discharge by the discharge resistor FR.

On the other hand, when the second charging voltage is higher than the voltage capable of continuing the discharge, the main control circuit CON controls the discharge control circuit FX so as to stop the discharge by the discharge resistor FR.

When the second charging voltage is equal to or lower than the discharge continuation possible voltage, the main control circuit CON determines that the smoothing capacitor FC by the discharge resistor FR until the charging voltage of the smoothing capacitor FC becomes equal to or lower than the third charging voltage smaller than the second charging voltage. The discharge control circuit FX may be controlled so as to continue the discharge. The third charging voltage is, for example, a voltage that is low enough to assume that discharging of the smoothing capacitor FC has been completed.

Further, when the second charging voltage is equal to or lower than the discharge continuation possible voltage, the main control circuit CON controls the discharge control circuit FX so as to maintain the connection of the discharge resistance FR to the smoothing capacitor FC, whereby the discharge resistance FR The discharge control circuit FX may be controlled so as to continue the discharge.

On the other hand, when the second charging voltage is larger than the voltage capable of continuing the discharge, the main control circuit CON controls the discharge control circuit FX so as to cut off the discharge resistance FR from the smoothing capacitor FC, thereby discharging by the discharge resistance FR. The discharge control circuit FX may be controlled to stop.

The coefficient used for calculating the discharge continuable voltage may be set so as to correlate with the minimum value of the discharge amount of the smoothing capacitor FC predicted when the set time elapses. The coefficient may be set so as to change according to the elapsed time from the start of discharge. In this case, the main control circuit CON may calculate the discharge continuable voltage by multiplying the first charging voltage by a coefficient when the elapsed time is the set time.

The main control circuit CON monitors the integrated value of the first charging voltage and the coefficient for each cycle in a monitoring cycle shorter than the set time from the start of discharge by the discharge resistor FR, and controls the discharge control circuit FX based on the monitoring result. May be. For example, the main control circuit CON compares the integrated value obtained by multiplying the first charging voltage and the coefficient for each monitoring period with the charging voltage of the smoothing capacitor FC actually detected in each monitoring period for each monitoring period, When the state where the actual charging voltage is smaller than the integrated value is maintained until the set time elapses, control may be performed to continue discharging by the discharge resistor FR.

Further, the main control circuit CON multiplies the first charging voltage by the second coefficient set so as to correlate with the maximum value of the discharge amount of the smoothing capacitor FC predicted when the set time elapses. The lower limit charging voltage of the smoothing capacitor FC predicted during the elapse of time may be calculated. Then, the main control circuit CON may control the discharge control circuit FX so as to continue the discharge by the discharge resistance when the second charging voltage is equal to or higher than the lower limit charging voltage.

When controlling the discharge control circuit FX so as to stop the discharge of the smoothing capacitor FC by the discharge resistor FR, the main control circuit CON controls the driving circuit Z to control the discharge of the smoothing capacitor FC by the motor M. Good. That is, the main control circuit CON may control the discharge of the smoothing capacitor FC by the motor M by controlling the first to sixth transistors Q1 to Q6.

Further, when the smoothing capacitor FC is connected to the battery B, the main control circuit CON detects the first charge voltage, calculates the discharge continuable voltage, detects the second charge voltage, and discharges the second charge voltage and discharge. The discharge control circuit FX may be controlled according to the comparison result with the continuable voltage.

Hereinafter, an operation example of the first embodiment will be described with reference to the flowchart of FIG. Note that the flowchart of FIG. 2 is repeated as necessary.

First, the main control circuit CON detects the first charging voltage before starting the discharge of the smoothing capacitor FC by the discharge resistor FR (step S1). The detection of the first charging voltage may be executed, for example, when the rotational speed of the rotor of the motor M is equal to or lower than a preset threshold speed.

After detecting the first charging voltage, the main control circuit CON calculates a discharge continuable voltage based on the detected first charging voltage and the coefficient stored in advance in the storage unit of the main control circuit CON (step) S2).

FIG. 3 is a graph of charging voltage showing an operation example of the electric vehicle control device 100 according to the first embodiment. In the example of FIG. 3, the main control circuit CON is a minimum coefficient set so as to correlate with the first charge voltage and the minimum value of the discharge amount of the smoothing capacitor FC, and from the start of discharge (ie, time t1). The product of the minimum coefficient when the elapsed time is the set time (that is, time t2) is calculated as the discharge continuable voltage.

After calculating the discharge continuation possible voltage, as shown in FIG. 2, the main control circuit CON controls the discharge control circuit FX so as to start the discharge of the smoothing capacitor FC by the discharge resistor FR (step S3).

After starting the discharge of the smoothing capacitor FC by the discharge resistor FR under the control of the discharge control circuit FX, the main control circuit CON determines whether or not the set period has elapsed from the start of the discharge (step S4).

When the set period has elapsed (step S4: Yes), the main control circuit CON detects the second charging voltage (step S5).

After detecting the second charging voltage, the main control circuit CON compares the detected second charging voltage with the calculated discharge continuable voltage, and determines whether or not the second charging voltage is equal to or lower than the discharge continuable voltage. Is determined (step S6).

When the second charging voltage is equal to or lower than the discharge continuation possible voltage (step S6: Yes), the main control circuit CON controls the discharge control circuit FX so as to continue the discharge by the discharge resistor FR (step S7). In the example of FIG. 3, the normal charging voltage transitions with a value smaller than the product of the minimum coefficient and the first charging voltage. Such a normal charging voltage is equal to or lower than the discharge continuable voltage at the time t2 when the set time has elapsed, that is, the second charging voltage. In this case, for example, the smoothing capacitor FC is continuously discharged by the discharge resistor FR until the discharge of the smoothing capacitor FC is completed.

On the other hand, as shown in FIG. 2, when the second charging voltage is not equal to or lower than the discharge continuation possible voltage (step S6: No), the main control circuit CON controls the discharge control circuit FX so as to stop the discharge by the discharge resistor FR. (Step S8). In the example of FIG. 3, the charging voltage at the time of abnormality transitions with a value larger than the product of the minimum coefficient and the first charging voltage. The charging voltage at the time of such an abnormality is greater than the voltage at which discharge can be continued at the time t2 when the set time has elapsed, that is, the second charging voltage. In this case, the discharge resistor FR is cut off from the smoothing capacitor FC by the discharge control circuit FX, and the discharge of the smoothing capacitor FC by the discharge resistor FR is stopped.

After performing the control for stopping the discharge by the discharge resistor FR (step S8), the main control circuit CON shifts to the discharge of the smoothing capacitor FC by the motor M by controlling the driving of the first to sixth transistors Q1 to Q6. May be.

As described above, in the electric vehicle control apparatus 100 according to the first embodiment, the main control circuit performs the first charging of the smoothing capacitor between the power supply terminal and the ground terminal before the discharge by the discharge resistor is started. Detect voltage. In addition, the main control circuit multiplies the first charging voltage by a preset coefficient before the preset set time elapses from the start of discharge by the discharge resistor, thereby predicting the discharge predicted when the preset time elapses. A discharge continuable voltage, which is a charging voltage of a smoothing capacitor capable of continuing discharge by a resistor, is calculated. The main control circuit detects the second charging voltage of the smoothing capacitor between the power supply terminal and the ground terminal when the set time has elapsed. Then, the main control circuit compares the second charging voltage with the discharge continuable voltage, and if the second charge voltage is equal to or lower than the discharge continuable voltage, the main control circuit sets the discharge control circuit to continue the discharge by the discharge resistor Control. On the other hand, the main control circuit controls the discharge control circuit to stop the discharge by the discharge resistance when the second charging voltage is larger than the voltage capable of continuing the discharge.

Thereby, according to the electric vehicle control device according to the first embodiment, when the second charging voltage becomes higher than the discharge continuable voltage, it is possible to stop the discharge due to the discharge resistance. As a result, it is possible to prevent a large voltage from being applied to the discharge resistor, so it is possible to prevent the amount of heat generated by the discharge resistor from becoming excessive, and to ensure the pressure resistance of the discharge resistor. Since it is not necessary to increase the discharge resistance, the discharge resistance can be reduced in size.

The main control circuit also discharges the smoothing capacitor by the discharge resistor until the charging voltage of the smoothing capacitor becomes equal to or lower than the third charging voltage smaller than the second charging voltage when the second charging voltage is equal to or lower than the discharge continuation possible voltage. The discharge control circuit can be controlled so as to continue. Thereby, the smoothing capacitor can be completely discharged.

Further, the main control circuit controls the discharge control circuit so as to maintain the connection of the discharge resistor to the smoothing capacitor when the second charge voltage is equal to or lower than the voltage at which the power can be continued, while the second charge voltage is When the voltage is higher than the discharge continuable voltage, the discharge control circuit can be controlled to cut off the discharge resistance from the smoothing capacitor. Thereby, continuation and a stop of discharge can be reliably performed with a simple configuration.

Also, the main control circuit can calculate the discharge continuable voltage before the start of discharge by the discharge resistor. Thereby, even when the set time is short, it is possible to reliably compare the discharge continuable voltage with the second charging voltage.

Also, the coefficient can be set so as to correlate with the minimum value of the smoothing capacitor discharge amount predicted when the set time elapses. Thereby, the discharge continuation possible voltage can be calculated accurately.

Further, the coefficient is set so as to change according to the elapsed time from the start of discharge, and the main control circuit multiplies the first charging voltage by the coefficient when the elapsed time is the set time, so that the discharge continuable voltage Can be calculated. Thereby, it is possible to calculate the discharge continuable voltage more accurately.

The main control circuit can monitor the integrated value of the first charging voltage and the coefficient for each cycle at a cycle shorter than the set time from the start of discharge by the discharge resistor, and control the discharge control circuit based on the monitoring result. it can. Thereby, the discharge by discharge resistance can be controlled more appropriately.

Further, the main control circuit multiplies the first charging voltage by a second coefficient set so as to correlate with the maximum value of the smoothing capacitor discharge amount predicted when the set time elapses. The lower limit charging voltage of the smoothing capacitor predicted at the time is calculated, and when the second charging voltage is equal to or higher than the lower limit charging voltage, the discharge control circuit can be controlled to continue discharging by the discharge resistance. Thereby, the discharge by discharge resistance can be controlled more appropriately.

The main control circuit can further control the operation of the drive circuit. Thereby, the discharge by the discharge resistor and the operation of the drive circuit can be controlled by a common control circuit, so that the number of parts can be suppressed.

Further, when the main control circuit controls the discharge control circuit so as to stop the discharge of the smoothing capacitor by the discharge resistor, the main control circuit can control the discharge of the smoothing capacitor by the motor by controlling the drive circuit. Thereby, when the discharge by the discharge resistor is stopped, the smoothing capacitor FC can be reliably discharged by switching to the discharge by the motor.

The drive circuit includes first to sixth transistors, and the main control circuit can control the discharge of the smoothing capacitor by the motor by controlling the first to sixth transistors. As a result, the discharge by the motor can be performed easily and reliably through the first to sixth transistors.

The main control circuit also detects the first charge voltage, calculates the discharge continuable voltage, detects the second charge voltage, and detects the second charge voltage and the discharge continuable voltage when the smoothing capacitor is connected to the battery. The discharge control circuit can be controlled in accordance with the comparison result. As a result, even when a large voltage is applied to the discharge resistor due to the smoothing capacitor connected to the battery, the discharge by the discharge resistor can be controlled so that the amount of heat generated by the discharge resistor does not become excessive.

(Second Embodiment)
Next, an electric vehicle control apparatus 100 according to a second embodiment will be described with reference to FIG.

In the first embodiment, the main control circuit CON directly detects the charging voltage of the smoothing capacitor FC.

On the other hand, in the second embodiment, the discharge control circuit FX detects the charging voltage VFC of the smoothing capacitor FC between the power supply terminal TB and the ground terminal TG.

Then, information on the charging voltage VFC is output to the main control circuit CON.

The main control circuit CON indirectly detects the charging voltage of the smoothing capacitor FC by inputting information from the discharge control circuit FX.

According to the second embodiment, the circuit configuration can be simplified as compared with the first embodiment.

Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

100 Electric Vehicle Control Device M Motor TB Power Terminal TG Ground Terminal FC Smoothing Capacitor FR Discharge Resistor FX Discharge Control Circuit Z Drive Circuit CON Main Control Circuit Q1 First Transistor Q2 Second Transistor Q3 Third Transistor Q4 Fourth Transistor Q5 First 5 transistor Q6 6th transistor

Claims

A smoothing connected between a power supply terminal connected to the positive electrode of the battery and a ground terminal connected to the negative electrode of the battery, and charged with a voltage supplied from the battery between the power supply terminal and the grounding terminal. A capacitor,
Between the power supply terminal and the ground terminal, connected in parallel with the smoothing capacitor, a discharge resistor for discharging the smoothing capacitor,
A discharge control circuit that is connected in series with the discharge resistor between the power supply terminal and the ground terminal, and controls discharge of the smoothing capacitor by the discharge resistor;
A main control circuit for controlling the operation of the discharge control circuit;
A drive circuit for driving the motor by supplying an AC voltage obtained by converting the DC voltage between the power supply terminal and the ground terminal to the motor; and
The main control circuit includes:
Detecting the first charging voltage of the smoothing capacitor between the power supply terminal and the ground terminal before starting discharge by the discharge resistor;
The discharge due to the discharge resistance predicted when the set time elapses by multiplying the first charging voltage and the preset coefficient before the preset set time elapses from the start of the discharge due to the discharge resistance. A discharge continuation possible voltage which is a charging voltage of the smoothing capacitor capable of continuation of
Detecting a second charging voltage of the smoothing capacitor between the power supply terminal and the ground terminal when the set time elapses;
Comparing the second charge voltage and the sustainable voltage;
When the second charge voltage is equal to or lower than the discharge continuable voltage, the discharge control circuit is controlled to continue the discharge by the discharge resistance, while the second charge voltage is higher than the discharge continuable voltage. And the discharge control circuit is controlled so as to stop the discharge by the discharge resistor.
The main control circuit includes:
When the second charging voltage is equal to or lower than the discharge continuation possible voltage, the smoothing capacitor is discharged by the discharge resistor until the charging voltage of the smoothing capacitor becomes equal to or lower than a third charging voltage smaller than the second charging voltage. The drive device according to claim 1, wherein the discharge control circuit is controlled to continue the operation.
The main control circuit includes:
When the second charging voltage is equal to or lower than the discharge continuation possible voltage, the discharge control circuit is controlled to maintain the connection of the discharge resistor to the smoothing capacitor, while the second charging voltage is 2. The driving device according to claim 1, wherein the discharge control circuit is controlled to cut off the discharge resistance from the smoothing capacitor when the voltage is higher than a discharge continuable voltage.
The main control circuit includes:
The drive device according to claim 1, wherein the discharge continuable voltage is calculated before the discharge by the discharge resistor is started.
2. The driving apparatus according to claim 1, wherein the coefficient is set so as to correlate with a minimum value of the discharge amount of the smoothing capacitor predicted when the set time elapses.
The coefficient is set to change according to the elapsed time from the start of the discharge,
The main control circuit includes:
5. The driving device according to claim 4, wherein the discharge continuable voltage is calculated by multiplying the first charging voltage by a coefficient when the elapsed time is the set time. 6.
The main control circuit monitors an integrated value of the first charging voltage and the coefficient for each cycle at a cycle shorter than the set time from the start of discharge by the discharge resistor, and the discharge control circuit based on a monitoring result The driving device according to claim 6, wherein the driving device is controlled.
The main control circuit includes:
By multiplying the first charging voltage by the second coefficient set so as to correlate with the maximum value of the discharge amount of the smoothing capacitor predicted when the set time elapses, the prediction is made when the set time elapses. Calculating a lower limit charging voltage of the smoothing capacitor,
5. The drive device according to claim 4, wherein when the second charging voltage is equal to or higher than the lower limit charging voltage, the discharge control circuit is controlled to continue discharging by the discharge resistor.
The driving apparatus according to claim 1, wherein the main control circuit further controls the operation of the driving circuit.
The main control circuit includes:
When the discharge control circuit is controlled to stop the discharge of the smoothing capacitor by the discharge resistor, the discharge of the smoothing capacitor by the motor is controlled by controlling the drive circuit. Item 9. The driving device according to Item 8.
The drive circuit is
A first transistor having one end connected to the power supply terminal and the other end connected to a first output terminal of a first phase;
A second transistor having one end connected to the power supply terminal and the other end connected to a second output terminal of the second phase;
A third transistor having one end connected to the power supply terminal and the other end connected to a third phase third output terminal;
A fourth transistor having one end connected to the first output terminal and the other end connected to the ground terminal;
A fifth transistor having one end connected to the second output terminal and the other end connected to the ground terminal;
A sixth transistor having one end connected to the third output terminal and the other end connected to the ground terminal;
The main control circuit includes:
10. The driving apparatus according to claim 9, wherein discharge of the smoothing capacitor by the motor is controlled by controlling the first to sixth transistors.
When the smoothing capacitor is connected to the battery, the main control circuit detects the first charging voltage, calculates the discharge continuable voltage, detects the second charging voltage, and the second charging voltage. 2. The driving device according to claim 1, wherein the discharge control circuit is controlled in accordance with a comparison result between the voltage and the discharge continuation possible voltage.
The discharge control circuit includes:
Detecting the first charging voltage and the second charging voltage, and outputting information on the first and second charging voltages to the main control circuit;
The main control circuit includes:
The driving apparatus according to claim 1, wherein the first and second charging voltages are detected by inputting the information.
An electric vehicle including a battery, a motor, and a drive device,
The driving device includes:
Connected between a power supply terminal connected to the positive electrode of the battery and a ground terminal connected to the negative electrode of the battery, and charged with a voltage supplied from the battery between the power supply terminal and the ground terminal. A smoothing capacitor;
Between the power supply terminal and the ground terminal, connected in parallel with the smoothing capacitor, a discharge resistor for discharging the smoothing capacitor,
A discharge control circuit that is connected in series with the discharge resistor between the power supply terminal and the ground terminal, and controls discharge of the smoothing capacitor by the discharge resistor;
A main control circuit for controlling the operation of the discharge control circuit;
A drive circuit for driving the motor by supplying an AC voltage obtained by converting a DC voltage between the power supply terminal and the ground terminal to the motor; and
The main control circuit includes:
Detecting the first charging voltage of the smoothing capacitor before starting discharge by the discharge resistor;
The discharge due to the discharge resistance predicted when the set time elapses by multiplying the first charging voltage and the preset coefficient before the preset set time elapses from the start of the discharge due to the discharge resistance. A discharge continuation possible voltage which is a charging voltage of the smoothing capacitor capable of continuation of
Detecting a second charging voltage of the smoothing capacitor when the set time elapses;
Comparing the second charge voltage and the sustainable voltage;
When the second charge voltage is equal to or lower than the discharge continuable voltage, the discharge control circuit is controlled to continue the discharge by the discharge resistance, while the second charge voltage is higher than the discharge continuable voltage. If it is too large, the discharge control circuit is controlled so as to stop the discharge by the discharge resistance.
A smoothing connected between a power supply terminal connected to the positive electrode of the battery and a ground terminal connected to the negative electrode of the battery, and charged with a voltage supplied from the battery between the power supply terminal and the grounding terminal. A capacitor,
Between the power supply terminal and the ground terminal, connected in parallel with the smoothing capacitor, a discharge resistor for discharging the smoothing capacitor,
A discharge control circuit that is connected in series with the discharge resistor between the power supply terminal and the ground terminal, and controls discharge of the smoothing capacitor by the discharge resistor;
A drive circuit that supplies an AC voltage obtained by converting a DC voltage between the power supply terminal and the ground terminal to a motor and drives the motor,
Detecting the first charging voltage of the smoothing capacitor before starting discharge by the discharge resistor;
The discharge due to the discharge resistance predicted when the set time elapses by multiplying the first charging voltage and the preset coefficient before the preset set time elapses from the start of the discharge due to the discharge resistance. A discharge continuation possible voltage which is a charging voltage of the smoothing capacitor capable of continuation of
Detecting a second charging voltage of the smoothing capacitor when the set time elapses;
Comparing the second charge voltage and the sustainable voltage;
When the second charge voltage is equal to or lower than the discharge continuable voltage, the discharge control circuit is controlled to continue the discharge by the discharge resistance, while the second charge voltage is higher than the discharge continuable voltage. If it is larger, the discharge control circuit is controlled so as to stop the discharge by the discharge resistance.