JP2003284330A - Control device, method for controlling, and computer readable recording medium recorded with program for making computer control voltage conversion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for controlling a DC voltage converter with the size of a switching element in actual use as a reference. <P>SOLUTION: A highest rated output current arithmetic circuit 3032 calculates a highest rated voltage current in response to an input voltage detected by an input voltage detecting circuit 3031. A highest rated output current varying circuit 3033 varies a set value of the highest rated output current in response to the calculated result of the circuit 3032. A rated-current excess deciding circuit 3034 decides whether an output current LCRT exceeds a set value of the highest rated output current or not. A MOSFET drive control circuit 3035 controls MOS transistors 251, 254 so as to suppress the current LCRT to the set value of the highest rated output current when the current LCRT exceeds the set value. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a DC voltage converter that changes the voltage level of a DC voltage, a control method for a DC voltage converter that changes the voltage level of a DC voltage, and a voltage level of a DC voltage. The present invention relates to a computer-readable recording medium in which a program for causing a computer to execute control of a DC voltage converter is recorded.

[0002]

2. Description of the Related Art Recently, hybrid vehicles and electric vehicles have been attracting much attention as environmentally friendly vehicles. And, the hybrid electric vehicle is partially put into practical use.

This hybrid vehicle uses a conventional engine and a motor driven by a DC power source or an inverter as a power source. That is, the power source is obtained by driving the engine, and the DC voltage from the DC power source is converted into AC by the inverter, and the motor is rotated by the converted AC to obtain the power source. An electric vehicle is a vehicle that uses a DC power source, an inverter, and a motor driven by the inverter as power sources.

In such a hybrid vehicle or electric vehicle, a system is also considered in which a DC voltage from a DC power source is boosted by a boost converter and the boosted DC voltage is supplied to an inverter for driving a motor. Has been done.

Further, in a hybrid vehicle or an electric vehicle, a direct current voltage from a direct current power source is stepped down and the stepped down direct current voltage is supplied to a load such as a light.

That is, a hybrid vehicle or an electric vehicle is equipped with an electric unit 500 shown in FIG. Referring to FIG. 9, electric unit 500 includes DC power supply B, system relays SR1 and SR2, voltage sensors 501 and 505, and capacitors 502, 504 and 510.
A converter 503, an inverter 506, a current sensor 507, a DC / DC converter 509, a load 511, and a control device 520.

The DC power source B outputs a DC voltage. The voltage sensor 501 detects the DC voltage of the DC power supply B and outputs it to the control device 520. System relay SR1, SR
2 is turned on by the control device 520, the DC voltage from the DC power supply B is transferred to the capacitor 502 and the DC / DC.
It is supplied to the converter 509. Capacitor 502 smoothes the DC voltage supplied from DC power supply B via system relays SR1 and SR2, and supplies the smoothed DC voltage to converter 503.

Converter 503 boosts the DC voltage supplied from capacitor 502 under the control of control unit 520, and boosts the DC voltage to capacitor 504.
Supply to. Capacitor 504 smoothes the DC voltage supplied from converter 503 and supplies it to inverter 506. The voltage sensor 505 detects the voltage on both sides of the capacitor 504, that is, the input voltage to the inverter 506.

When the DC voltage is supplied from the capacitor 504, the inverter 506 converts the DC voltage into an AC voltage under the control of the control device 520 to drive the motor 508. As a result, the motor 508 is driven to generate the torque designated by the torque command value.

DC / DC converter 509 lowers the DC voltage supplied from DC power source B via system relays SR1 and SR2 in accordance with a control signal from control device 520, and reduces the reduced DC voltage to capacitor 510. Supply to. The capacitor 510 is the DC / DC converter 5
09 smoothes the DC voltage supplied thereto, and supplies the smoothed DC voltage to the load 511. And the load 51
1 is driven by the supplied DC voltage.

The control device 520 controls the converter 503 and the inverter 50 based on the voltage from the voltage sensor 501, the motor current from the current sensor 507, and the like.
6 is generated, and the generated control signal is output to converter 503 and inverter 506. Further, the control device 520 generates a control signal for controlling the DC / DC converter 509 to generate the DC / D.
Output to the C converter 509.

When the motor 508 and the load 511 are driven, the controller 520 controls the system relays SR1 and SR.
Turn on 2. Then, DC power supply B outputs a DC voltage, and system relays SR1 and SR2 output the DC voltage output from DC power supply B to capacitor 502 and DC / D.
It is supplied to the C converter 509. Also, the voltage sensor 5
01 detects the DC voltage of the DC power supply B to detect the control device 52
0 to the voltage sensor 505 and the capacitor 504
Of both ends of the current, that is, the input voltage to the inverter 506 is detected and output to the control device 520.
07 detects the motor current and outputs it to the controller 520.

The controller 520 controls the DC voltage of the DC power source,
A control signal for driving converter 503 and inverter 506 is generated based on an input voltage to inverter 506, a motor current, and the like, and the generated control signal is output to converter 503 and inverter 506.

On the other hand, capacitor 502 smoothes the DC voltage supplied from system relays SR1 and SR2 and supplies it to converter 503. The converter 503 converts the DC voltage supplied from the capacitor 502 into the control device 5
The voltage is boosted in accordance with the control signal from 20, and the boosted DC voltage is supplied to the capacitor 504. Capacitor 504
Supplies the DC voltage supplied from the converter 503 to the inverter 506 after smoothing it. Then, the inverter 506 converts the DC voltage supplied from the capacitor 504 into an AC voltage according to the control signal from the control device 520, and supplies the converted AC voltage to the motor 508 to drive the motor 508. As a result, the motor 508
Generate a predetermined torque.

The controller 520 also controls the DC / DC converter 50 so as to step down the DC voltage from the DC power supply B.
9, the DC / DC converter 509 steps down the DC voltage from the DC power supply B and supplies it to the capacitor 510. The capacitor 510 is a DC / DC converter 509.
The DC voltage reduced by is smoothed and supplied to the load 511. As a result, the load 511 is driven.

As described above, the electric unit 500 mounted on the hybrid vehicle or the electric vehicle drives the motor 508 so as to boost the DC voltage from the DC power source B and generate a predetermined torque, and at the same time, the DC power source. The DC voltage from B is stepped down to drive the load 511.

A DC / DC converter for stepping down the DC power supply from the high voltage power supply side of the vehicle to the low voltage power supply side is disclosed in Japanese Patent Application Laid-Open No. 11-299003.

[0018]

Conventional electric unit 5
The DC / DC converter 509 included in 00 is configured to form the DC / DC converter 509 because the DC voltage from the DC voltage B is stepped down and driven by the control device 520 so that the stepped down DC voltage becomes constant. When the input voltage to the DC / DC converter 509 decreases, the switching element tries to flow a large amount of current in order to keep the output voltage constant. That is, as shown in FIG. 10, when the input voltage is high, the switching element is turned on for a short time, but when the input voltage is lowered, the switching element is turned on for a long time. Then, the loss in the switching element becomes large. The loss in the switching element becomes maximum when the energizing current of the switching element is maximum (that is, the load current is maximum) and the energizing time is maximum (that is, the input voltage is minimum).

The size of the switching element is determined in consideration of the current flowing and the loss in the switching element. Therefore, it is necessary to determine the size of the switching element so that a current sufficient to keep the output voltage constant can flow through the switching element even if the input voltage is the lowest. That is, even if the input voltage becomes the lowest, DC / DC
It is necessary to determine the size of the switching element so that a large current for keeping the output voltage of the converter constant can flow through the switching element.

However, in actual operation, DC / D
The frequency at which the input voltage to the C converter becomes the lowest is low,
The size of the switching element becomes excessively large in the actual use state. As a result, there arises a problem that the cost of the switching element does not decrease.

Therefore, the present invention has been made in order to solve such a problem, and its object is to make the size of the switching element in the actual use state as a reference.
An object of the present invention is to provide a control device that controls a DC voltage conversion device.

Another object of the present invention is to set the size of the switching element in the actual use state as a reference,
It is to provide a control method for controlling a DC voltage converter.

Still another object of the present invention is a computer-readable recording medium in which a program for causing a computer to control a DC voltage converter based on the size of a switching element in an actual use state is recorded. Is to provide.

[0024]

According to the present invention, the control device is a control device for a DC voltage converter that changes the voltage level of the DC voltage, and controls the input voltage to the DC voltage converter. Detecting means for detecting, and a deciding means for deciding the maximum rated output current indicating the maximum value of the operating current of the DC voltage converter so as to suppress the input voltage when the detected input voltage is low, and When the output current of the DC voltage converter exceeds the maximum rated output current, there is provided a suppressing means for suppressing the output current.

Preferably, the determining means calculates the maximum rated current that can be output by the DC voltage converter according to the voltage level of the input voltage, the current value of the calculated maximum rated current, and the maximum rating. Changing means for changing the current value of the maximum rated output current according to the relationship between the output current and the current value.

Preferably, the changing means compares the difference between the calculated current value of the maximum rated current and the current value with a predetermined value, and changes the current value of the maximum rated output current according to the comparison result. .

Preferably, the calculating means holds a map showing the relationship between the input voltage and the maximum rated current, and calculates the maximum rated current corresponding to the input voltage based on the map.

Preferably, the DC voltage converter is a transformer type DC-DC converter.

Preferably, the DC voltage converter is a chopper type DC-DC converter.

Further, according to the present invention, the control method is a method for controlling a DC voltage converter which changes the voltage level of the DC voltage, and which detects the input voltage to the DC voltage converter.
Depending on the step and the voltage level of the detected input voltage,
And, a second step of determining a maximum rated output current showing the maximum value of the operating current of the DC voltage converter so as to suppress when the input voltage drops, and a third step of detecting the output current of the DC voltage converter. And a fourth step of suppressing the output current when the detected output current exceeds the maximum rated output current.

Preferably, in the second step, the first sub-step of calculating the maximum rated current that can be output by the DC voltage converter according to the voltage level of the input voltage, and the current of the calculated maximum rated current And a second sub-step of changing the current value of the maximum rated output current according to the relationship between the value and the current value of the maximum rated output current.

Preferably, the second sub-step comprises a step of comparing the difference between the calculated current value of the maximum rated current and the current value with a predetermined value, and a maximum rated output current according to the comparison result. Changing the current value of

Preferably, in the first substep, the maximum rated current is calculated based on the map showing the relationship between the input voltage and the maximum rated current.

Further, according to the present invention, a computer-readable recording medium in which a program for causing a computer to control a DC voltage converter for changing the voltage level of a DC voltage is recorded is input to the DC voltage converter. The first step of detecting the voltage and the maximum rated output current indicating the maximum value of the operating current of the DC voltage converter is determined according to the detected voltage level of the input voltage and so as to suppress when the input voltage drops. Cause the computer to execute the second step, the third step of detecting the output current of the DC voltage converter, and the fourth step of suppressing the output current when the detected output current exceeds the maximum rated output current. It is a computer-readable recording medium in which a program for recording is recorded.

Preferably, in the second step, the first sub-step of calculating the maximum rated current that can be output by the DC voltage converter according to the voltage level of the input voltage, and the current of the calculated maximum rated current And a second sub-step of changing the current value of the maximum rated output current according to the relationship between the value and the current value of the maximum rated output current.

Preferably, the second sub-step comprises a step of comparing the difference between the calculated current value of the maximum rated current and the current value with a predetermined value, and a maximum rated output current according to the comparison result. Changing the current value of

Preferably, in the first substep, the maximum rated current is calculated based on the map showing the relationship between the input voltage and the maximum rated current.

Therefore, according to the present invention, the size of the switching element which constitutes the DC voltage converter may be determined based on the actual use condition, and the size of the switching element can be made smaller than the conventional one. As a result, the cost of the switching element can be reduced.

[0039]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts will be denoted by the same reference characters and description thereof will not be repeated.

Referring to FIG. 1, an electric unit 100 including a control device according to an embodiment of the present invention includes a DC power source B, voltage sensors 10, 13, 27 and 28, system relays SR1 and SR2, and Capacitors C1 to C3,
A boost converter 12, an inverter 14, current sensors 24 and 29, and a controller 30 are provided.

The motor M1 is a drive motor for generating torque for driving the drive wheels of a hybrid vehicle or an electric vehicle. Alternatively, this motor has the function of a generator driven by an engine, and operates as an electric motor for the engine, for example,
It may be incorporated in a hybrid vehicle so that the engine can be started.

The load 26 is various auxiliary equipment or electric components mounted in a vehicle such as a light and an inverter for an air conditioner mounted in a hybrid vehicle or an electric vehicle.

The boost converter 12 includes a reactor L1.
, NPN transistors Q1 and Q2, and diode D
1 and D2 are included. One end of reactor L1 is connected to the power supply line of DC power supply B, and the other end is connected to the midpoint between NPN transistor Q1 and NPN transistor Q2, that is, between the emitter of NPN transistor Q1 and the collector of NPN transistor Q2. It The NPN transistors Q1 and Q2 are connected in series between the power supply line and the ground line. And the NPN transistor Q
The collector of 1 is connected to the power supply line, and the emitter of the NPN transistor Q2 is connected to the ground line. In addition, diodes D1 and D2 for flowing a current from the emitter side to the collector side are arranged between the collector and the emitter of each NPN transistor Q1 and Q2.

The inverter 14 includes a U-phase arm 15 and a V-phase arm 15.
It comprises a phase arm 16 and a W phase arm 17. The U-phase arm 15, the V-phase arm 16, and the W-phase arm 17 are provided in parallel between the power supply line and the ground.

The U-phase arm 15 is an NPN connected in series.
It is composed of transistors Q3 and Q4, and the V-phase arm 16 is
It consists of NPN transistors Q5 and Q6 connected in series, and the W-phase arm 17 consists of NPN transistors Q7 and Q8 connected in series. Further, diodes D3 to D8 for flowing a current from the emitter side to the collector side are respectively connected between the collector and the emitter of each NPN transistor Q3 to Q8.

The midpoint of each phase arm is connected to each phase end of each phase coil of the motor M1. That is, the motor M
1 is a three-phase permanent magnet motor, which has three phases of U, V, and W
One end of each coil is commonly connected to the middle point, and U
The other end of the phase coil is at the midpoint between the NPN transistors Q3 and Q4, and the other end of the V phase coil is the NPN transistors Q5 and Q4.
The other end of the W-phase coil is connected to the intermediate point of 6 and the intermediate points of the NPN transistors Q7 and Q8, respectively.

The DC power source B is composed of a secondary battery such as nickel hydrogen or lithium ion. And DC power supply B
Outputs a DC voltage of about 280V, for example. The voltage sensor 10 has a voltage V1 output from the DC power supply B.
Is detected and the detected voltage V1 is output to the control device 30. The system relays SR1 and SR2 include the control device 30.
It is turned on by the signal SE from. The capacitor C1 is
The DC voltage supplied from DC power supply B is smoothed, and the smoothed DC voltage is supplied to boost converter 12.

Boost converter 12 boosts the DC voltage supplied from capacitor C1 and supplies it to capacitor C2. More specifically, when boost converter 12 receives signal PWU from control device 30, boost converter 12 boosts the DC voltage in accordance with the period during which NPN transistor Q2 is turned on by signal PWU and supplies the boosted voltage to capacitor C2. in this case,
The NPN transistor Q1 is turned off by the signal PWU. Further, the boost converter 12 includes a control device 30.
When receiving the signal PWD from, the DC voltage supplied from the inverter 14 via the capacitor C2 is stepped down to charge the DC power supply B. The boost converter 12 boosts the DC voltage of about 280V supplied from the capacitor C1 to about 500V and supplies it to the capacitor C2.

Capacitor C2 smoothes the DC voltage from boost converter 12 and supplies the smoothed DC voltage to inverter 14. The voltage sensor 13 detects the voltage across the capacitor C2, that is, the input voltage IVV to the inverter 14, and detects the detected input voltage IVV.
Is output to the control device 30.

The inverter 14 receives the signal PWMI from the controller 30 when the DC voltage is supplied from the capacitor C2.
The DC voltage is converted into an AC voltage based on the above, and the motor M1 is driven. As a result, the motor M1 has the torque command value T
It is driven to generate the torque specified by R. Further, the inverter 14 converts the AC voltage generated by the motor M1 into a DC voltage based on the signal PWMC from the control device 30 during the regenerative braking of the hybrid vehicle or the electric vehicle in which the electric unit 100 is mounted, and converts the AC voltage. The DC voltage is supplied to the boost converter 12 via the capacitor C2. The regenerative braking referred to here is braking accompanied by regenerative power generation when there is a foot brake operation by a driver who drives a hybrid vehicle or an electric vehicle, or the accelerator pedal is turned off while driving, although the foot brake is not operated. This includes decelerating (or stopping acceleration) the vehicle while causing regenerative power generation.

The current sensor 24 detects the motor current MCRT flowing through the motor M1 and outputs the detected motor current MCRT to the control device 30.

The voltage sensor 27 detects the input voltage V2 to the DC / DC converter 25 and outputs it to the control device 30. The DC / DC converter 25 reduces the DC voltage supplied from the DC power supply B by the signal MDRS from the control device 30 and supplies the DC voltage to the capacitor C3. in this case,
The DC / DC converter 25 steps down an input voltage of about 280V to about 14V and supplies it to the capacitor C3.

The capacitor C3 smoothes the DC voltage from the DC / DC converter 25 and supplies it to the load 26.
As a result, the load 26 is driven. Voltage sensor 28
Detects the output voltage V3 of the DC / DC converter 25 and outputs it to the control device 30. The current sensor 29 is DC
The output current LCRT of the / DC converter 25 is detected and output to the control device 30.

The control device 30 is an ECU provided outside.
(Electrical Control Unit)
Command value TR and motor speed M input from
Based on RN, the voltage V1 from the voltage sensor 10, the input voltage IVV from the voltage sensor 13, and the motor current MCRT from the current sensor 24, a signal PWU and an inverter 14 for driving the boost converter 12 are generated by a method described later. A signal PWMI for driving is generated, and the generated signal PWU and signal PWMI are output to boost converter 12 and inverter 14, respectively. The signal PWU indicates that the boost converter 12 has a capacitor C.
This is a signal for driving the boost converter 12 when converting the DC voltage from 1 into the input voltage IVV.

When the control device 30 receives a signal RGE indicating that the hybrid vehicle or the electric vehicle has entered the regenerative braking mode from the external ECU, the motor M1.
A signal PWMC for converting the AC voltage generated by the above into a DC voltage is generated and output to the inverter 14. In this case, the NPN transistors Q4, Q6 of the inverter 14 are
The switching of Q8 is controlled by the signal PWMC.
That is, the NPN transistors Q6 and Q8 are turned on when the U phase of the motor M1 is generated, the NPN transistors Q4 and Q8 are turned on when the V phase is generated, and the NPN transistors Q4 and Q6 are generated when the W phase is generated. Turned on. As a result, the inverter 14 converts the AC voltage generated by the motor M1 into a DC voltage, and the boost converter 1
Supply to 2.

Further, the control device 30 includes the voltage sensor 2
7, an input voltage V2 from the voltage sensor 28, an output voltage V3 from the voltage sensor 28, and an output current LCRT from the current sensor 29.
Based on the above, a signal MDRS for controlling the DC / DC converter 25 is generated by a method described later, and the generated signal MDRS is output to the DC / DC converter 25.

Further, control device 30 generates a signal SE for turning on system relays SR1 and SR2 and outputs it to system relays SR1 and SR2.

FIG. 2 is a functional block diagram of the control device 30. Referring to FIG. 2, control device 30 includes a motor torque control unit 301, a voltage conversion control unit 302, and a converter control unit 303. Motor torque control means 3
01 is the torque command value TR, the output voltage V of the DC power supply B
1, the motor current MCRT, the motor speed MRN, and the input voltage IVV to the inverter 14,
1 is driven, the signal PWU for turning on / off the NPN transistors Q1 and Q2 of the boost converter 12 and the NPN transistor Q of the inverter 14 by the method described later.
A signal PWMI for turning on / off 3 to Q8 is generated, and the generated signal PWU and signal PWMI are output to boost converter 12 and inverter 14, respectively.

The voltage conversion control means 302, during regenerative braking,
When a signal RGE indicating that the hybrid vehicle or the electric vehicle has entered the regenerative braking mode is received from the external ECU, a signal PWD for stepping down the DC voltage supplied from the inverter 14 is generated and output to the step-up converter 12. . As described above, the boost converter 12 has the function of a bidirectional converter because it can also lower the voltage by the signal PWD for lowering the DC voltage. Further, the voltage conversion control unit 302 receives the signal RGE from the external ECU during regenerative braking, and then the motor M
1 generates a signal PWMC for converting the AC voltage generated by 1 into a DC voltage and outputs the signal to the inverter 14.

The converter control means 303 uses DC / DC
Input voltage V2 to converter 25, output voltage V3 of DC / DC converter 25, and DC / DC converter 25
A signal MDRS is generated by a method described later based on the output current LCRT of the above and output to the DC / DC converter 25.

FIG. 3 is a functional block diagram of the motor torque control means 301. Referring to FIG. 3, motor torque control unit 301 includes motor control phase voltage calculation unit 40, inverter PWM signal conversion unit 42, inverter input voltage command calculation unit 50, and converter duty ratio calculation unit 52. , And a converter PWM signal converter 54.

The motor control phase voltage calculator 40 receives the input voltage IVV to the inverter 14 from the voltage sensor 13, the motor current MCRT flowing in each phase of the motor M1 from the current sensor 24, and the torque command value TR to the outside. EC
Receive from U. Then, the motor control phase voltage calculator 40
Calculates the voltage applied to the coil of each phase of the motor M1 based on these input signals, and outputs the calculated result to the inverter PWM signal conversion unit 42. The inverter PWM signal conversion unit 42 generates a signal PWMI that actually turns on / off the NPN transistors Q3 to Q8 of the inverter 14 based on the calculation result received from the motor control phase voltage calculation unit 40, and generates the signal PWMI. Signal P
WMI is connected to each NPN transistor Q3 of the inverter 14
Output to Q8.

As a result, each NPN transistor Q3 ...
Q8 is switching-controlled and controls the current flowing through each phase of the motor M1 so that the motor M1 outputs the commanded torque. In this way, the motor drive current is controlled,
The motor torque corresponding to the torque command value TR is output.

On the other hand, the inverter input voltage command calculator 50
Calculates the optimum value (target value) of the inverter input voltage based on the torque command value TR and the motor rotation speed MRN,
The calculated optimum value is output to converter duty-ratio calculation unit 52.

Converter duty-ratio calculator 52
Is a duty ratio for setting the input voltage IVV from the voltage sensor 13 to the optimum value output from the inverter input voltage command calculator 50 based on the output voltage V1 (battery voltage V1) from the voltage sensor 10. Calculate The converter PWM signal conversion unit 54 includes the NPN transistor Q1 of the boost converter 12 based on the duty ratio from the converter duty ratio calculation unit 52.
A signal PWU for turning on / off Q2 is generated. Then, converter PWM signal conversion unit 54 outputs the generated signal PWU to NPN transistors Q1 and Q2 of boost converter 12. Then, NPN transistors Q1 and Q2 of boost converter 12 are turned on / off based on signal PWU. As a result, the boost converter 1
2 converts the DC voltage so that the input voltage IVV becomes the optimum value.

The NPN on the lower side of the boost converter 12
By increasing the on-duty of the transistor Q2, the power storage in the reactor L1 increases, so that a higher voltage output can be obtained. On the other hand, increasing the on-duty of the upper NPN transistor Q1 lowers the voltage of the power supply line. So N
By controlling the duty ratios of the PN transistors Q1 and Q2, it is possible to control the voltage of the power supply line to any voltage higher than the output voltage of the DC power supply B.

Referring to FIG. 4, DC / DC converter 2
Reference numeral 5 includes MOS transistors 251-254, transformers 255, 256, diodes 257, 258, a coil 259, and a capacitor 260.

The MOS transistors 251, 252 are connected in series between the power supply line 31 and the ground line 32. The MOS transistors 253 and 254 are connected in series between the power supply line 31 and the ground line 32. The MOS transistors 251, 252 are connected in parallel with the MOS transistors 253, 254 between the power supply line 31 and the ground line 32.

The transformer 255 has one end connected to the node N1 between the MOS transistor 251 and the MOS transistor 252, and the other end connected to the MOS transistor 2.
It is connected to a node N2 between 53 and MOS transistor 254.

The transformer 256 is provided so as to face the transformer 255. The diode 257 is the transformer 256.
Is connected between the transformer 256 and the coil 259 so that the output current Io flows from the coil to the coil 259.

Diode 258 is connected between transformer 256 and node N3 so as to block current from node N3 between diode 257 and coil 259 to the low voltage side of transformer 256. The coil 259 is connected between the diode 257 and the load 26.

The capacitor 260 is connected between the output side of the coil 259 and the ground node 261 and is connected to the coil 259.
The output voltage from is smoothed and supplied to the load 26.

When the MOS transistors 251 and 254 are turned on and the MOS transistors 252 and 253 are turned off, the power supply line 31, the MOS transistor 251, the node N1, the transformer 255, the node N2, the MOS transistor 254 and the earth line 32 are connected. Input current I
in flows. Then, the transformers 255 and 256 step down the input voltage Vin according to the winding ratio and output the output voltage Vo.

On the secondary side of the DC / DC converter 25,
The output current Io is provided in the path of the transformer 256, the diode 257, the coil 259, the load 26, and the ground node 261.
Flows.

Depending on the ratio at which the MOS transistors 251 and 254 are turned on / off, that is, the duty ratio,
The input current Iin changes and the voltage applied to the transformer 255 changes. That is, the MOS transistor 25
As the duty ratio of 1 and 254 increases, the input current Iin increases and the voltage applied to the transformer 255 increases. Further, when the duty ratio of the MOS transistors 251, 254 decreases, the input current Iin decreases and the voltage applied to the transformer 255 decreases.

Since the transformers 255 and 256 step down the voltage applied to the transformer 255 according to the voltage level, the output voltage Vo on the secondary side of the DC / DC converter 25 is applied to the transformer 255. It changes according to the voltage.

The converter control means 303 includes a maximum rated output current calculation circuit 3032, a maximum rated output current variable circuit 3033, a rated current over determination circuit 3034, and an M
An OSFET drive control circuit 3035 is included.

The input voltage detection circuit 3031 is composed of the voltage sensor 27, detects the input voltage Vin, and detects the input voltage V
2 is output to the maximum rated output current calculation circuit 3032.

The maximum rated output current calculation circuit 3032 responds to the input voltage V2 from the input voltage detection circuit 3031 according to the input voltage V2.
MOS transistor 251 of DC / DC converter 25
Calculate a maximum rated output current of ~ 254. More specifically, the maximum rated output current calculation circuit 3032 calculates the maximum rated output current according to the input voltage V2 according to the curve k1 shown in FIG.

Referring to FIG. 5, the maximum rated output current calculation circuit 3032 has an input voltage V2 of Vinmin to Vin1.
When the input voltage V2 is in the range Vin1 to Vin2, the maximum rated output current is increased so as to increase in proportion to the input voltage V2. Calculate and input voltage V2 is Vin2
When it is in the range of to Vinmax, the maximum rated output current is calculated to have a constant value I2.

The maximum rated output current arithmetic circuit 3032
Holds the relationship between the input voltage of the curve k1 shown in FIG. 5 and the maximum rated output current as a map. When receiving the input voltage V2 from the input voltage detection circuit 3031, the input voltage V2 is changed to the input voltage V2 based on the held map. Determine the corresponding maximum rated output current.

Conventionally, MOS transistors 251 to 254
The maximum rated output current was constant even if the input voltage varied in the range from the lower limit value Vinmin to the upper limit value Vinmax as shown by the straight line k2. Therefore, when the input voltage drops, the energizing current flowing through the MOS transistors 251 to 254 is controlled to increase within the range of the maximum rated output current. As a result, if the input voltage drops,
MOS transistor 2 in order to pass more current
It was necessary to increase the size of 51-254.

On the other hand, in the present invention, when the input voltage decreases, the MOS transistors 251 to 254.
Since the maximum rated output current of 1 is suppressed, when the input voltage drops, the conduction current of the MOS transistors 251 to 254 is suppressed to the maximum rated output current I1 or less, and the size of the MOS transistors 251 to 254 can be made smaller than before.
As a result, the MOS that constitutes the DC / DC converter 25
The cost of the transistors 251 to 254 can be reduced.

As described above, in the present invention, the MOS
The maximum rated output current of the transistors 251 to 254 is set to DC
It is characterized in that the maximum rated output current is reduced when the input voltage is lowered by changing it according to the voltage level of the input voltage to the / DC converter 25.

Referring again to FIG. 4, the maximum rated output current variable circuit 3033 includes a maximum rated output current calculation circuit 303.
The maximum rated output current calculated by 2 is received, and the actual set value of the maximum rated output current is varied based on the received maximum rated output current. More specifically, the maximum rated output current varying circuit 3033 varies the actual set value of the maximum rated output current so as to be smaller than the maximum rated output current determined by the curve k1 shown in FIG. 5 by a constant value. .

The rated current over determination circuit 3034 receives the set value of the maximum rated output current varied by the maximum rated output current varying circuit 3033 and the output current LCRT detected by the current sensor 29, and the maximum output current LCRT is obtained. Determine if the set value of rated output current is exceeded. When the rated current over determination circuit 3034 determines that the output current LCRT exceeds the set value of the maximum rated output current, the signal RSTR for suppressing the output current LCRT from the set value of the maximum rated output current is MOSFET-driven. Output to the control circuit 3035. When the rated current over determination circuit 3034 determines that the output current LCRT does not exceed the set value of the maximum rated output current, the output current LC
A signal HLD for holding RT is output to the MOSFET drive control circuit 3035.

Upon receiving the signal RSTR from the rated current over determination circuit 3034, the MOSFET drive control circuit 3035 receives a signal DTDW for reducing the duty ratio of the MOS transistors 251, 254 and a signal for turning off the MOS transistors 252, 253. A signal MDRS composed of STP is generated, the signal DTDW is output to the gate terminals of the MOS transistors 251 and 254, and the signal STP is output to the gate terminals of the MOS transistors 252 and 253.

In this case, the MOSFET drive control circuit 30
35 is a voltage conversion ratio by the transformers 255 and 256,
That is, the conversion ratio when the input voltage Vin is stepped down to the output voltage Vo is held. The MOSFET drive control circuit 3035 receives the output voltage V3 detected by the voltage sensor 28, and based on the duty ratios of the MOS transistors 251 and 254 at which the current output voltage V3 is output and the conversion ratios of the transformers 255 and 256. hand,
A duty ratio for obtaining an output voltage V3 for making the output current LCRT smaller than the set value of the maximum rated output current is calculated, and a signal DTDW for driving the MOS transistors 251 and 254 is generated by the duty ratio to generate a MOS. Output to the gate terminals of the transistors 251 and 254.

Further, the MOSFET drive control circuit 3035
Receives the signal HLD from the rated current over determination circuit 3034, the signals DTHLD and M for holding the current duty ratios of the MOS transistors 251 and 254.
A signal MDRS including a signal STP for turning off the OS transistors 252 and 253 is generated, and a signal DTHL is generated.
D is output to the gate terminals of the MOS transistors 251 and 254, and the signal STP is output to the MOS transistors 252 and 25.
Output to the gate terminal of 3.

Thus, the converter control means 303
Is the MOS transistor 25 of the DC / DC converter 25 according to the input voltage V2 to the DC / DC converter 25.
Set the maximum rated output current setting value from 1 to 254 to DC
The MOS transistors 251 and 254 are driven so that the output current LCRT of the / DC converter 25 does not exceed the set value of the varied maximum rated output current.

The operation of suppressing the output current LCRT of the DC / DC converter 25 below the set value of the maximum rated output current will be described with reference to FIGS. 6 and 7. Figure 6
FIG. 7 is a flowchart for explaining the overall operation of suppressing the output current LCRT below the set value of the maximum rated output current, and FIG. 7 is step S of the flowchart shown in FIG.
2 is a flowchart for explaining detailed operations of S2 and S3.

Referring to FIG. 6, when the operation is started, input voltage detection circuit 3031 detects input voltage V2, and detects detected input voltage V2 at maximum rated output current operation circuit 30.
It outputs to 32 (step S1). Then, the maximum rated output current calculation circuit 3032 is configured so that the input voltage detection circuit 3031
The maximum rated output current is calculated according to the input voltage V2 from (step S2).

Thereafter, the maximum rated output current variable circuit 303
3 changes the set value of the maximum rated output current according to the calculation result of the maximum rated output current calculation circuit 3032 (step S3). Then, the rated current over determination circuit 3034
Determines whether the output current from the current sensor 29 exceeds the set value set by the maximum rated output current variable circuit 3033 (step S4). When it is determined that the output current exceeds the set value, the maximum output current is set. The signal RSTR for suppressing the set value of the rated output current is output to the MOSFET drive control circuit 3035.

Upon receiving the signal RSTR, the MOSFET drive control circuit 3035 receives the signal DT by the method described above.
D MD is generated by generating a signal MDRS composed of DW and signal STP.
Output to the C / DC converter 25. This allows DC
/ DC converter 25 MOS transistors 251 and 2
54 is driven with a small duty ratio of ON,
The output current is suppressed below the set value of the maximum rated output current (step S5). Then, the process returns to step S1.

On the other hand, in step S4, when the rated current over determination circuit 3034 determines that the output current does not exceed the set value, the signal HL for holding the output current is held.
D is output to the MOSFET drive control circuit 3035. Then, the MOSFET drive control circuit 3035 outputs the signal HL
When receiving D, it generates a signal MDRS composed of the signal DTHLD and the signal STP and outputs it to the DC / DC converter 25. As a result, the DC / DC converter 25 holds the output current constant (step S6). Then, a series of operations ends (step S7).

The detailed operation of steps S2 and S3 of the flowchart shown in FIG. 6 will be described with reference to FIG. After step S1, the maximum rated output current calculation circuit 30
32 determines whether or not the input voltage input from the input voltage detection circuit 3031 is a variably controllable lower limit value (step S21). Then, the maximum rated output current calculation circuit 303
1 is when the input voltage is determined to be the lower limit value that can be variably controlled, that is, when the input voltage is from the voltage Vinmin to Vi.
When it is determined that it is within the range of n1 (see FIG. 5), the maximum rated output current is set to the lower limit value I1 (step S2).
2). Then, it transfers to step S31.

On the other hand, in step S21, when the maximum rated output current arithmetic circuit 3032 determines that the input voltage is not lower than or equal to the lower limit value for which variable control is possible, it determines whether or not the input voltage is the upper limit value for variable control (step S21). Step S23).
Then, when the maximum rated output current calculation circuit 3032 determines that the input voltage exceeds the upper limit value that can be variably controlled, that is, the input voltage is between the voltages Vin2 and Vinmax (see FIG. 5).
If it is determined to be within the range of (see), the maximum rated output current is set to the upper limit value I2 (step S24). Then, it transfers to step S31.

In step S23, when the maximum rated output current calculation circuit 3032 determines that the input voltage does not exceed the variably controllable upper limit value, the maximum rated output current calculation circuit 3032 adjusts the maximum rated output current according to the input voltage so that the loss becomes constant. Is calculated (step S25). That is, the maximum rated output current calculation circuit 3
When determining that the input voltage is within the range of voltages Vin1 and Vin2 (see FIG. 5), 032 calculates the maximum rated output current so as to increase in proportion to the input voltage.

As described above, steps S21 to S25
Is the detailed operation of step S2 in FIG.

After steps S22, S24 and S25, the maximum rated output current variable circuit 3033 receives the calculation result of the maximum rated output current calculation circuit 3032 and calculates the difference between the calculation result and the current set value. Then, the maximum rated output current variable circuit 3033 determines whether or not the calculated difference is larger than 5 A (step S31), and the difference is 5
When it is larger than A, a value obtained by subtracting 5 A from the current set value is set as a new set value of the maximum rated output current (step S32). Then, the process proceeds to step S4 shown in FIG.

On the other hand, the maximum rated output current variable circuit 3033
When it is determined in step S31 that the difference is not larger than 5A, it is determined whether the calculated difference is smaller than -5A (step S33), and when it is determined that the difference is smaller than -5A, A value obtained by adding 5 A to the current set value is set as a new set value of the maximum rated output current (step S34). Then, the process proceeds to step S4 shown in FIG.

When it is determined in step S33 that the difference is not smaller than -5 A, the maximum rated output current variable circuit 3033 sets the current set value as a new set value (step S35). Then, step S4 shown in FIG.
Move to.

As described above, steps S31 to S35.
Is the detailed operation of step S3 shown in FIG.

Referring again to FIG. 1, the electric unit 10
The operation at 0 will be described. When a torque command value TR is input from an external ECU, control device 30 generates a signal SE for turning on system relays SR1 and SR2 and outputs the signal SE to system relays SR1 and SR2, and motor M1 outputs a torque command. Signal PWU and signal PWMI for controlling boost converter 12 and inverter 14 to generate value TR are generated and output to boost converter 12 and inverter 14, respectively.

Then, the DC power supply B outputs a DC voltage,
System relays SR1 and SR2 supply a DC voltage to capacitor C1 and DC / DC converter 25. Capacitor C1 smoothes the supplied DC voltage and supplies the smoothed DC voltage to boost converter 12.

Then, the NPN of the boost converter 12 is
The transistors Q1 and Q2 are connected to the signal P from the control device 30.
It is turned on / off according to WU, converts a DC voltage, and supplies the DC voltage to the capacitor C2. The voltage sensor 13 detects the input voltage IVV to the inverter 14, which is the voltage across the capacitor C2, and outputs the detected input voltage IVV to the control device 30.

Capacitor C2 smoothes the DC voltage from boost converter 12 and supplies the smoothed DC voltage to inverter 14. The inverter 14 converts the DC voltage supplied from the capacitor C2 into an AC voltage based on the signal PWMI from the control device 30 to convert the motor M1.
To drive. As a result, the motor M1 generates the torque designated by the torque command value TR.

Further, control device 30 generates signal MDRS and outputs it to DC / DC converter 25 as described above. The DC / DC converter 25 steps down the DC voltage supplied from the DC power supply B and supplies it to the capacitor C3. The capacitor C3 smoothes the output voltage V3 from the DC / DC converter 25 and supplies the smoothed DC voltage to the load 26. As a result, the load 26 is driven.

During regenerative braking of a hybrid vehicle or electric vehicle equipped with the electric unit 100, the control device 3
0 receives a signal RGE indicating that the regenerative braking mode has been entered from the external ECU, and according to the received signal RGE,
The signal PWMC and the signal PWD are generated by the method described above, and the generated signal PWMC and the signal PWD are output to the inverter 14 and the boost converter 12, respectively.

The motor M1 generates an AC voltage and supplies it to the inverter 14. The inverter 14 is a control device 30.
The AC voltage is converted into a DC voltage according to the signal PWMC from and the converted DC voltage is supplied to the boost converter 12 via the capacitor C2. Then, boost converter 12 responds to signal PWD from control device 30.
The DC voltage supplied from the inverter 14 is stepped down to charge the DC power supply B via the capacitor C1 and the system relays SR1 and SR2.

In the above description, the DC / DC converter is the transformer type DC / DC converter 25. However, in the present invention, the DC / DC converter is the chopper type DC / DC converter 25A shown in FIG.
May be

The DC / DC converter 25A includes NPN transistors Q10 and Q11 and diodes D10 and D1.
1 and a reactor L2.

One end of reactor L2 is connected to the power supply line of load 26, and the other end is connected to NPN transistor Q10.
And the NPN transistor Q11, that is, N
It is connected between the emitter of PN transistor Q10 and the collector of NPN transistor Q11. The NPN transistors Q10 and Q11 are connected in series between the power supply line 31 and the ground line 32. The collector of NPN transistor Q10 is connected to power supply line 31, and the emitter of NPN transistor Q11 is connected to ground line 32. Also, each NPN transistor Q1
Diodes D10 and D11 for passing a current from the emitter side to the collector side are arranged between the collector and the emitter of 0 and Q11.

DC / DC converter is a chopper type DC
/ DC converter 25A, the MOSFET drive control circuit 3035 of the converter control means 303 is DC
/ DC converter 25A NPN transistor Q10,
A signal TDRS for turning on / off Q11 is generated and output to NPN transistors Q10 and Q11. DC /
When the DC converter 25A steps down the DC voltage, NP
Since the N transistor Q10 is turned on and the NPN transistor Q11 is turned off, the signal TDRS includes a signal for turning on / off the NPN transistor Q10 at a predetermined duty ratio and a signal for turning off the NPN transistor Q11. . And the NPN transistor Q
The signal for turning on / off 10 at a predetermined duty ratio is determined according to the rate of reducing the DC voltage. When the rate of reducing the DC voltage is large, the NPN transistor Q
The ON period of 10 is set short, and the ON period of the NPN transistor Q10 is set short when the ratio of reducing the DC voltage is small. Then, the DC / DC converter 25A
In the case where the output current of 1 is suppressed below the set value set by the maximum rated output current varying circuit 3033, the NPN transistor Q10 is driven by the same method.

Control of voltage conversion in DC / DC converter 25A is performed according to the flow charts shown in FIGS. 6 and 7 described above.

The DC / DC converters 25, 25A
The voltage conversion control in the
Ral Processing Unit), the CPU executes a program (ROM) that includes the steps of the flowcharts shown in FIGS. 6 and 7.
(Only Memory), the read program is executed, and the MOS transistors 251 to 254 of the DC / DC converter 25 or the DC / DC converter 2 are executed according to the flowcharts shown in FIGS. 6 and 7.
The maximum rated output current of the 5A NPN transistors Q10 and Q11 is varied according to the input voltage to control the step-down of the DC voltage supplied from the DC power supply B to the output voltage. Therefore, the ROM corresponds to a computer (CPU) readable recording medium in which a program including the steps of the flowcharts shown in FIGS. 6 and 7 is recorded.

According to the embodiment of the present invention, the control device for the voltage conversion device is controlled so as to respond to the input voltage of the DC / DC converter and to suppress when the input voltage decreases.
Since the maximum rated output current of the switching element included in the C / DC converter is varied, the DC / DC converter is provided with a control means for driving the switching element so that the output current of the DC / DC converter does not exceed the maximum rated output current. The size of the switching element constituting the above may be determined on the basis of the actual usage state, and the size of the switching element can be made smaller than in the conventional case. As a result, the cost of the switching element can be reduced.

The embodiments disclosed this time are to be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of an electric unit according to an embodiment of the present invention.

FIG. 2 is a functional block diagram of the control device shown in FIG.

FIG. 3 is a functional block diagram for explaining the function of the motor torque control means shown in FIG.

4 is a circuit diagram of the DC / DC converter shown in FIG. 1 and a functional block diagram of converter control means shown in FIG.

FIG. 5 is a diagram showing the relationship between the maximum rated output current and the input voltage.

FIG. 6 is a flowchart for explaining an operation of suppressing the output current of the DC / DC converter shown in FIG. 1 above the set value of the maximum rated output current.

FIG. 7 is a step S2 of the flowchart shown in FIG.
It is a flow chart for explaining a detailed operation of S3.

FIG. 8 is a circuit diagram of a chopper type DC / DC converter.

FIG. 9 is a conventional functional block diagram of an electric unit mounted in a hybrid vehicle or an electric vehicle.

FIG. 10 is a diagram showing a change in a current flowing through a MOSFET due to a change in an input voltage.

[Explanation of symbols]

10, 13, 27, 28, 501, 504 Voltage sensor, 12 Boost converter, 14, 506 Inverter, 15 U phase arm, 16 V phase arm, 17 W phase arm, 24, 29, 507 Current sensor, 25, 25
A, 509 DC / DC converter, 26, 511 load, 30, 520 control device, 31 power supply line, 32
Earth line, 40 Motor control phase voltage calculator, 4
2 inverter PWM signal converter, 50 inverter input voltage command calculator, 52 converter duty ratio calculator, 54 converter PWM signal converter, 10
0,500 electric unit, 251-254 MOS transistor, 255,256 transformer, 259 coil, 261 ground node, 301 motor torque control means, 302 voltage conversion control means, 303 converter control means, 503 converter, 3031 input voltage detection circuit, 3032 Maximum rated output current arithmetic circuit, 3033
Maximum rated output current variable circuit, 3034 Rated current over determination circuit, 3035 MOSFET drive control circuit,
B DC power supply, SR1, SR2 system relay, C
1, C2, 260, 502, 504, 510 Capacitor, L1, 311 reactor, Q1 to Q11, 31
2,313 NPN transistors, D1 to D11,25
7,258 diode, M1,508 motor.

Continued front page    F-term (reference) 5H115 PC06 PG04 PI16 PU01 PU21                       PV05 PV09 PV23 PV24 RB22                       SE03 SE10 TO12 TO13                 5H410 BB01 BB02 BB05 CC05 DD02                       DD04 DD06 DD09 EA10 EB01                       EB13 EB15 EB16 EB25 EB37                       EB39 FF03 FF05 FF22 FF24                       FF25 GG03 GG07 HH05 LL04                       LL06                 5H730 AA20 AS01 AS04 AS05 AS13                       AS19 BB11 BB14 BB21 BB57                       DD02 FD01 FD11 FD21 FD31                       FF09 FG05 FG26 XX02 XX03                       XX13 XX15 XX22 XX23 XX33                       XX35 XX47

Claims (14)

[Claims] 1. A controller for a DC voltage converter that changes the voltage level of a DC voltage, comprising: detection means for detecting an input voltage to the DC voltage converter; And, the determining means for determining the maximum rated output current showing the maximum value of the operating current of the DC voltage converter so as to suppress when the input voltage drops, the output current of the DC voltage converter is the maximum rated output current And a control unit that suppresses the output current. 2. The determining means calculates a maximum rated current that can be output by the DC voltage converter according to the voltage level of the input voltage, and a current value of the calculated maximum rated current. The control device according to claim 1, further comprising: a changing unit that changes a current value of the maximum rated output current according to a relationship between the maximum rated output current and a current current value. 3. The changing means compares the difference between the calculated current value of the maximum rated current and the current value with a predetermined value, and according to the comparison result, the current value of the maximum rated output current. The control device according to claim 2, wherein 4. The calculating means holds a map showing the relationship between the input voltage and the maximum rated current, and calculates the maximum rated current corresponding to the input voltage based on the map. The control device according to claim 2 or claim 3. 5. The control device according to claim 1, wherein the DC voltage converter is a transformer type DC-DC converter. 6. The control device according to claim 1, wherein the DC voltage converter is a chopper type DC-DC converter. 7. A method of controlling a DC voltage converter for changing a voltage level of a DC voltage, comprising: a first step of detecting an input voltage to the DC voltage converter; And a second step of determining a maximum rated output current indicating the maximum value of the operating current of the DC voltage converter so as to suppress the input voltage when the input voltage drops, and detecting the output current of the DC voltage converter And a fourth step of suppressing the output current when the detected output current exceeds the maximum rated output current. 8. The second step comprises a first sub-step of calculating a maximum rated current that can be output by the DC voltage converter according to a voltage level of the input voltage, and the calculated maximum rating. The control according to claim 7, further comprising a second substep of changing the current value of the maximum rated output current according to the relationship between the current value of the current and the current current value of the maximum rated output current. Method. 9. The second sub-step comprises the step of comparing a difference between the calculated current value of the maximum rated current and the current value with a predetermined value, and the second sub-step according to the comparison result. 9. The control method according to claim 8, further comprising: changing a current value of the maximum rated output current. 10. The method according to claim 8, wherein in the first sub-step, the maximum rated current is calculated based on a map showing a relationship between the input voltage and the maximum rated current. Control method. 11. A computer-readable recording medium in which a program for causing a computer to control a DC voltage converter that changes the voltage level of a DC voltage is recorded, wherein the input voltage to the DC voltage converter is detected. And a maximum rated output current that indicates a maximum value of the operating current of the DC voltage converter according to the detected voltage level of the input voltage and that is suppressed when the input voltage drops. A second step; a third step of detecting the output current of the DC voltage converter; and a fourth step of suppressing the output current when the detected output current exceeds the maximum rated output current. A computer-readable recording medium recording a program to be executed by a computer. 12. The second step comprises a first sub-step of calculating a maximum rated current that can be output by the DC voltage converter according to a voltage level of the input voltage, and the calculated maximum rating. The computer according to claim 11, further comprising a second sub-step of changing the current value of the maximum rated output current according to the relationship between the current value of the current and the current current value of the maximum rated output current. A computer-readable recording medium recording a program to be executed by a computer. 13. The second sub-step includes the step of comparing a difference between the calculated current value of the maximum rated current and the current value with a predetermined value, and the step of comparing the difference according to the comparison result. The computer-readable recording medium which recorded the program for making a computer execute the computer according to claim 12, including the step of changing the current value of the maximum rated output current. 14. The maximum rated current in the first sub-step is calculated based on a map showing a relationship between the input voltage and the maximum rated current.
A computer-readable recording medium recording the program to be executed by the computer according to claim 13.