JP2006115643A - Control device for load drive circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily correct a plurality of voltage detection sensors provided in a load drive circuit.
If the SMR is not ON (NO in S100), the ECU corrects the zero of the VL sensor and the VH sensor to eliminate the offset (S120), and the SMR is ON and the power supply of the electric load circuit Is not ON (YES in S100 and NO in S110), the step of correcting the output point of the VL sensor using the output value of the VB sensor (S130), and the VL using the corrected zero point and output point A program including the step of creating a sensor characteristic map (S180) is executed.
[Selection] Figure 2

Description

  The present invention relates to an electric circuit for driving a load mounted on a vehicle, and more particularly to a technique for improving the detection accuracy of a plurality of sensors provided in the load driving circuit.

  In recent years, hybrid vehicles and electric vehicles have attracted much attention as environmentally friendly vehicles. Some hybrid vehicles have already been put to practical use.

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

  In such a hybrid vehicle or electric vehicle, there is a case where the voltage is boosted by a DC / DC converter from a low-voltage battery and electric power is supplied to the motor inverter. In this case, the rated voltage of the driving motor is high in order to reduce the current supplied to the motor for driving the vehicle to reduce the weight of the harness and to obtain a high driving force for driving the vehicle. There are many cases. On the other hand, in order to increase the voltage of the battery mounted on the vehicle, many battery cells of about 1.2V must be connected in series. If the rated voltage of the motor does not reach even when many are connected in series, the voltage of the battery is boosted by the DC / DC converter and supplied to the motor via the inverter. As described above, in the electric circuit mounted on the vehicle, it is necessary to step up / down the voltage of the battery. In such a case, a DC / DC converter is used. In such an electric circuit, the voltage at a plurality of locations is detected to control the step-up / step-down voltage of the DC / DC converter or to detect the voltage of the battery (power source).

  Japanese Unexamined Patent Publication No. 2000-308384 (Patent Document 1) discloses a motor control device that controls the operation of a motor by controlling a voltage applied from a power source to a coil of the motor. In this motor control device, the sensor that detects the power supply voltage may include an error in the detection value due to the influence of the environment in which the motor is used. Since this occurs as an offset error, it is made in view of the fact that the motor cannot output the required torque. The motor control device includes a voltage estimation unit that estimates a voltage value of a power source, a detection voltage application unit that applies a predetermined detection voltage to the coil based on the estimated voltage value, and a coil that corresponds to the detection voltage. Current detecting means for detecting the current value flowing in the motor, error specifying means for specifying the detected voltage value and an error of the voltage value estimated based on the current value, and reflecting the specified error, the motor Voltage application control means for applying a predetermined voltage to the coil according to the operating state.

According to this motor control device, the torque voltage to be applied to the motor is set according to the required torque, and the duty of the inverter is controlled so that the torque voltage is applied according to the voltage of the battery. In the motor control device configured as described above, before starting normal operation of the motor, the inverter is switched at a constant duty to apply a voltage to the motor. In addition, the current flowing according to this voltage is detected. If the relationship between the power supply voltage and current when the inverter is switched at a constant duty is stored in advance as a table, the true value of the power supply voltage can be obtained and the offset error occurring in the battery voltage sensor can be specified. Can do. Therefore, it is possible to appropriately control the torque voltage by correcting the detected voltage value of the battery.
JP 2000-308384 A

  However, in the motor control device disclosed in Patent Document 1, the relationship between the power supply voltage and current detected under a predetermined condition must be stored in advance as a table. Further, the predetermined condition must be that the inverter is switched at a constant duty.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to control a load driving circuit capable of easily correcting a plurality of voltage detection sensors provided in the load driving circuit. Is to provide.

  A control device according to a first aspect of the present invention includes a converter that performs a transformation operation, a battery connected to an input side of the converter, an electric load circuit provided between the battery and the converter, and the battery and the electric load circuit. A load driving circuit including a relay that switches to a connected state or a disconnected state is controlled. The control device detects a voltage value on the output side of the converter, a second detection means for detecting a voltage value on the input side of the converter, a first detection means for detecting the voltage value of the battery. Third detecting means for controlling and a control means for correcting a detection error of the detecting means. The control means includes a zero point correction means for correcting the voltage value detected by the second detection means and the third detection means to 0 when the battery and the electric load circuit are not connected by the relay. When the battery and the electric load circuit are connected by the relay and the electric load circuit is not in operation, the first detection means and the second detection means are more reliable. And a correction means for correcting the other detection means using a high detection means.

  According to the first invention, when the battery and the electrical load circuit are not connected by the relay, the battery power is not supplied to the load side (the electrical load circuit and the converter). The true voltage value detected by the detection means is zero. For this reason, the zero point correction means corrects the voltage value detected by the second detection means and the third detection means to 0 and eliminates the offset. When the battery and the electric load circuit are connected by the relay and the electric load circuit is not in operation, the voltage value detected by the first detection means and the second detection means are detected. The voltage value is the same. At this time, for example, when the first detection means is more reliable than the second detection means, the second detection means is corrected using the voltage value detected by the first detection means. In this way, offset can be eliminated, and reliability can be improved by adapting to highly reliable detection means. As a result, it is possible to provide a control device for a load driving circuit capable of easily correcting the detection means for detecting a plurality of voltages provided in the load driving circuit.

  In the control device according to the second invention, in addition to the configuration of the first invention, the control means is connected to the battery and the electric load circuit by the relay, and the electric load circuit is operating. When the converter is in a state and is not performing a transformation operation, the most reliable detection means among the first detection means, the second detection means, and the third detection means is used. Further included is a correcting means for correcting the detecting means.

  According to the second invention, when the battery and the electric load circuit are connected by the relay, the electric load circuit is in operation, and the converter is not performing the transformation operation, The voltage value detected by the first detection means, the voltage value detected by the second detection means, and the voltage value detected by the third detection means are the same. At this time, for example, when the first detection means is more reliable than the second detection means and the third detection means, the second detection is performed using the voltage value detected by the first detection means. The means and the third detecting means are corrected. In this way, offset can be eliminated, and reliability can be improved by adapting to highly reliable detection means. As a result, it is possible to provide a control device for a load driving circuit capable of easily correcting the detection means for detecting a plurality of voltages provided in the load driving circuit.

  In the control device according to the third invention, in addition to the configuration of the first or second invention, the control means performs the correction process of the second detection means when the electric load circuit is in operation. It further includes means for prohibiting.

  According to the third invention, when the electric load circuit is operating, the voltage value detected by the first detection means and the voltage value detected by the second detection means are not the same. Incorrect correction can be avoided by prohibiting the correction processing of the second detection means.

  In the control device according to the fourth invention, in addition to the configuration of the first or second invention, the control means prohibits the correction processing of the third detection means when the converter is performing a transformation operation. These means are further included.

  According to the fourth aspect of the invention, when the converter is performing a transformation operation, the voltage value detected by the first detection means is not the same as the voltage value detected by the third detection means. Incorrect correction can be avoided by prohibiting correction processing of the detection means.

  In the control device according to the fifth invention, in addition to the configuration of any one of the first to fourth inventions, the first detection means is based on the value of the resistance connected to the battery and the current value of the battery. Means for detecting the voltage value of the battery.

  According to the fifth invention, the voltage value of the battery is calculated using the value of the resistance connected to the battery and the current value of the battery, and the other detection means can be corrected using the voltage value. .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  With reference to FIG. 1, an overall circuit of a load drive circuit including an ECU (Electronic Control Unit) 1000 which is a control device according to an embodiment of the present invention will be described. Such a load drive circuit is mounted on a hybrid vehicle or an electric vehicle.

  This load drive circuit is a circuit that boosts the voltage of the main battery 100 by a boost DC / DC converter 700 and supplies electric power to the vehicle drive motor via an inverter. Between main battery 100 and step-up DC / DC converter 700, a system main relay (SMR) 500 and an electric load circuit 600 including auxiliary devices are connected.

  The main battery 100 is, for example, a secondary battery having a discharge voltage of 200 to 300 [V] in which nickel hydride batteries having a discharge voltage per cell of 1.2 [V] are connected in series. The step-up DC / DC converter 700 boosts the voltage of 200 to 300 [V] to about 500 to 600 [V], which is the rated voltage of the vehicle driving motor. The step-up DC / DC converter 700 is controlled by a control signal from the ECU 1000.

  The system main relay 500 is a relay (relay) that switches the main battery 100, the electric load circuit 600, and the step-up DC / DC converter 700 to either an electrically connected state or an electrically disconnected state. This system main relay 500 is controlled by a control signal from ECU 1000. For example, ECU 1000 outputs a control signal for switching the state of system main relay 500 in accordance with the state of the ignition switch of the vehicle.

  As an example of the auxiliary machines constituting the electric load circuit 600, an air conditioner 610 (more specifically, an electric compressor for an air conditioner and an electric motor for a blower fan) and a low-voltage battery 630 (for an auxiliary machine) A DC / DC converter 620 that steps down the voltage of the main battery 100 in order to charge a lead storage battery having a discharge voltage of about 12 [V] is shown. The DC / DC converter 620 steps down the discharge voltage of the main battery 100 from 200 to 300 [V] to about 14 [V] as the charging voltage of the low voltage battery 630. Similar to the system main relay 500 described above, the operation of these auxiliary machines is controlled by a control signal from the ECU 1000.

  In such a drive load circuit, a VB sensor 410 (first voltage detecting means) for detecting the voltage of the main battery 100 and a VL sensor 420 for detecting the voltage on the input side of the step-up DC / DC converter 700 are included. (Second voltage detection means) and a VH sensor 430 (third voltage detection means) for detecting the voltage on the output side of the step-up DC / DC converter 700. The voltage value VB detected by the VB sensor 410, the voltage value VL detected by the VL sensor 420, and the voltage value VH detected by the VH sensor 430 are respectively input to the ECU 1000.

  The drive load circuit is further provided with a current sensor 200 that detects the current value of the main battery 100 and a resistor 300 that is connected to the main battery 100. The resistance value of the resistor 300 is accurately stored in the ECU 1000. The current value IB detected by the current sensor 200 is input to the ECU 1000 and used for calculation together with the stored resistance value to calculate the voltage value of the main battery 100.

  With reference to FIG. 2, a control structure of a program executed by ECU 1000 which is the control apparatus according to the present embodiment will be described. In the following description, it is assumed that the VB sensor 410 has the highest reliability, but the present invention is not limited to such an assumption.

  In step (hereinafter step is abbreviated as S) 100, ECU 1000 determines whether or not system main relay 500 is in an ON state. Since the ECU 1000 itself outputs a control signal to the system main relay 500, the state of the system main relay 500 can be determined inside the ECU 1000. If system main relay 500 is in the ON state (YES in S100), the process proceeds to S110. If not (NO in S100), the process proceeds to S120.

  In S110, ECU 1000 determines whether or not the power supply of electric load circuit 600 composed of auxiliary machinery is ON. Since the ECU 1000 itself outputs a control signal to the electric load circuit 600 constituted by the auxiliary machines, it is possible to determine the state of the power source of the electric load circuit 600 constituted by the auxiliary machines inside the ECU 1000. If the power supply of electric load circuit 600 composed of auxiliary equipment is ON (YES in S110), the process proceeds to S160. If not (NO in S110), the process proceeds to S130.

  In S120, ECU 1000 corrects the zero point (point of 0 [V]) of VL sensor 420 and VH sensor 430.

  In S130, ECU 1000 corrects the output point of VL sensor 420 using the output value of VB sensor 410.

  In S140, ECU 1000 determines whether step-up DC / DC converter 700 is in the ON state (during step-up operation). Since the ECU 1000 itself outputs a control signal to the step-up DC / DC converter 700, the operation state of the step-up DC / DC converter 700 can be determined inside the ECU 1000. If step-up DC / DC converter 700 is in the ON state (during step-up operation) (YES in S140), the process proceeds to S170. If not (NO in S140), the process proceeds to S150.

  In S150, ECU 1000 corrects the output point of VH sensor 430 using the output value of VB sensor 410. Thereafter, the process ends.

  In S160, ECU 1000 prohibits the correction process for the output point of VL sensor 420. Thereafter, the process ends. In S170, ECU 1000 prohibits the correction process for the output point of VH sensor 430. Thereafter, the process ends.

  In S180, ECU 1000 sets the zero point (point of 0 [V]) corrected in S120 for VL sensor 420 and the correction of VL sensor 420 using VB sensor 410 having higher reliability in S130. Using the output points, a characteristic correction formula or map of the VL sensor 420 is created.

  In step S190, the ECU 1000 sets the zero point (0 [V] point) corrected in step S120 for the VH sensor 430 and the VH sensor 430 corrected in step S150 using the more reliable VB sensor 410. Using the output points, a characteristic correction formula or map of the VH sensor 430 is created. Thereafter, the process ends.

  The operation of the control device according to the present embodiment based on the structure and flowchart as described above will be described.

  If system main relay 500 is not in the ON state (NO in S100), power is not supplied from main battery 100, so the true voltage value to be detected by VL sensor 420 and VH sensor 430 must be zero. Therefore, in such a case, the zero point (0 [V] point) correction of the VL sensor 420 and the VH sensor 430 is performed, and the offset is eliminated.

  If system main relay 500 is in the ON state (YES in S100) and the power source of the load electric circuit composed of the auxiliary devices is not in the ON state (NO in S110), more reliable VB sensor 410 The output point of the VL sensor 420 is corrected using the output value (S130). At this time, the voltage value detected by the VL sensor 420 is matched with the voltage value detected by the VB sensor 410. That is, since the system main relay 500 is in the ON state and the power supply of the load electric circuit is not in the ON state, the true voltage values to be detected by the VB sensor 410 and the VL sensor 420 must be the same. Therefore, in such a case, the VL sensor 420 is corrected using the VB sensor 410.

  After the processing is performed in this way, that is, the VL sensor 420 is zero-corrected and corrected using the VB sensor 410, and then corrected to the corrected zero (0 [V] point). The characteristic correction formula or map of the VL sensor 420 is created using the output points of the VL sensor 420 (S180).

  System main relay 500 is in the ON state (YES in S100), the power source of the load electric circuit composed of auxiliary equipment is not in the ON state (NO in S110), and step-up DC / DC converter 700 is in the ON state Otherwise (NO in S140), the output point of VH sensor 430 is corrected using the more reliable output value of VB sensor 410 (S150). At this time, the voltage value detected by the VH sensor 430 is adapted to the voltage value detected by the VB sensor 410. That is, since the system main relay 500 is in the ON state and the power source of the load electric circuit is not in the ON state and the step-up DC / DC converter 700 is not in the ON state, it should be detected by the VB sensor 410, the VL sensor 420, and the VH sensor 430. The true voltage value must be the same. Therefore, in such a case, the VH sensor 420 is corrected using the VB sensor 410.

  After the processing is performed as described above, that is, the VH sensor 430 is corrected to the zero point and corrected using the VB sensor 410, the corrected zero point (0 [V] point) is corrected. Using the output point of the VH sensor 430, a characteristic correction formula or map of the VH sensor 430 is created (S190).

  The correction state of the VL sensor 420 will be described with reference to FIG. The same applies to the VH sensor 430.

  The characteristic indicated by the one-dot chain line in FIG. 3 has an offset before the zero point correction. By the process of S120, the offset is eliminated as in the characteristics indicated by the two-dot chain line. That is, when the true voltage value is 0 [V], it matches the sensor voltage lower limit value.

  After such offset error correction, the output value of the VL sensor 420 is corrected using the output value of the VB sensor 410 by the process of S130, and the inclination is corrected as shown by the characteristic indicated by the solid line.

  As described above, when the system main relay is not in the ON state, the zero point is corrected to eliminate the offset, and when the system main relay is in the ON state and the power of the auxiliary equipment is not in the ON state, the reliability of the VB sensor. Is assumed to be high, the VL sensor is corrected by the VB sensor. Further, when the step-up DC / DC converter is not in the ON state, the VH sensor is corrected by the VB sensor. In this way, it is possible to easily correct the voltage sensor that detects a plurality of voltages provided in the load drive circuit.

  In the above-described embodiment, another voltage sensor is configured using the voltage value of the main battery 100 detected by the VB sensor 410, but the battery detected by the current sensor 200 instead of the VB sensor 410. A value calculated from the current value IB and the resistance value of the resistor 300 may be used as the voltage value VB of the main battery 100.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is an overall circuit diagram of a load driving circuit including a control device according to an embodiment of the present invention. It is a flowchart which shows the control structure of the program performed with ECU of FIG. It is a figure which shows the correction | amendment state of a voltage sensor.

Explanation of symbols

  100 main battery, 200 current sensor, 300 resistor, 410 VB sensor, 420 VL sensor, 430 VH sensor, 500 system main relay (SMR), 600 electric load circuit, 610 air conditioner, 620 DC / DC converter, 630 low pressure Battery, 700 step-up DC / DC converter, 1000 ECU.

Claims (5)

A converter for performing a transformation operation, a battery connected to an input side of the converter, an electric load circuit provided between the battery and the converter, and connection and disconnection of the battery and the electric load circuit. A control device for a load drive circuit including a relay for switching to any state,
First detecting means for detecting the voltage value of the battery;
Second detection means for detecting a voltage value on the input side of the converter;
Third detection means for detecting a voltage value on the output side of the converter;
Control means for correcting the detection error of the detection means,
The control means includes
Zero point correcting means for correcting the voltage value detected by the second detecting means and the third detecting means to 0 when the battery and the electric load circuit are not connected by the relay; ,
When the battery and the electric load circuit are connected by the relay and the electric load circuit is not in operation, the first detecting means and the second detecting means And a correction means for correcting the other detection means using a more reliable detection means.   The control means is such that the battery and the electric load circuit are connected by the relay, the electric load circuit is operating, and the converter is not performing a transformation operation. Sometimes, a correction means for correcting other detection means by using the most reliable detection means among the first detection means, the second detection means, and the third detection means is further provided. The control apparatus of Claim 1 containing.   3. The control device according to claim 1, wherein the control unit further includes a unit for prohibiting the correction process of the second detection unit when the electric load circuit is operating. 4.   The control device according to claim 1, wherein the control unit further includes a unit for prohibiting the correction process of the third detection unit when the converter is performing a transformation operation.   The said 1st detection means contains the means for detecting the voltage value of the said battery based on the value of the resistance connected to the said battery, and the electric current value of the said battery, The any one of Claims 1-4 The control device described in 1.

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