Step-up control device and step-up device

Abstract

To provide a voltage boosting control device and a voltage boosting device capable of assuring higher stability than conventional device in control mode change in occurrence of abnormality.SOLUTION: A control device of a voltage boosting circuit, providing at least one switching leg consists of an upper arm switch and a lower arm switch, for generating an output voltage from an input voltage by setting a duty ratio of the upper arm switch by an upper arm driving signal and setting a duty ratio of the lower arm switch by a lower arm driving signal, includes a duty ratio setting part for setting a lower arm duty ratio command value so that the lower arm switch is fixed to an OFF state and setting an upper arm duty ratio command value using the input voltage and / or the output voltage before occurrence of abnormality, if an occurrence of abnormality is detected.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a boost control device and a boost device.

Background Art

[0002] Patent Document 1 below discloses a power supply device for a vehicle. As shown in FIGS. 1, 2, 4, etc. of Patent Document 1, this power supply device includes a hybrid control unit 31 and an overvoltage protection circuit 33 that restricts the operation of the boost converter 12 when the output of the voltage sensor exceeds the overvoltage threshold value. The hybrid control unit 31 determines whether an abnormality has occurred in the overvoltage protection circuit 33, and when it is determined that an abnormality has occurred in the overvoltage protection circuit 33, the boost converter 12 is operated in an evacuation mode different from the normal mode. The evacuation mode includes, at least, an upper arm ON mode that controls the boost converter 12 so as to be fixed in a state where the power line is electrically connected.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the background art, during the evacuation travel of the vehicle in the evacuation mode, the upper arm ON control of the boost converter is performed. However, since the control mode of the boost converter is switched from the normal mode to the evacuation mode in a state where the function has failed due to a failure or the like, there is a risk that the switching stability of the control mode during the occurrence of an abnormality cannot be sufficiently ensured.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a boost control device and a boost device capable of ensuring higher switching stability of the control mode during the occurrence of an abnormality than in the prior art.

Means for Solving the Problem

[0006] In order to achieve the above object, in the present invention, as a first solution means for a boost control device, at least one switching leg composed of an upper arm switch and a lower arm switch is provided, and the ON / OFF duty ratio of the upper arm switch is set by an upper arm drive signal, and the ON / OFF duty ratio of the lower arm switch is set by a lower arm drive signal, thereby generating an output voltage from an input voltage. A boost control device for controlling a boost circuit, when detecting an occurrence of an abnormality, sets a lower arm duty ratio command value so that the lower arm switch is fixed in an OFF state, and sets an upper arm duty ratio command value using the input voltage and / or the output voltage before the occurrence of the abnormality. A duty ratio setting unit is provided, and the means described above is adopted.

[0007] In the present invention, as a second solution means for a boost control device, in the above first solution means, the duty ratio setting unit averages the command value of the output voltage before the occurrence of the abnormality and the input voltage after the occurrence of the abnormality, and uses the result of the averaging process. The means of setting the upper arm duty ratio command value is adopted.

[0008] In the present invention, as a third solution means for a boost control device, in the above first solution means, the duty ratio setting unit averages the input voltage and / or the output voltage before the occurrence of the abnormality and the input voltage and / or the output voltage after the occurrence of the abnormality, and uses the result of the averaging process. The means of setting the upper arm duty ratio command value is adopted.

[0009] In the present invention, as a fourth solution means for a boost control device, in the above third solution means, when the duty ratio setting unit detects an abnormality of an input voltage sensor for detecting the input voltage, the result of averaging the input voltage before the occurrence of the abnormality and the input voltage after the occurrence of the abnormality is divided by the output voltage, thereby setting the upper arm duty ratio command value. The means described above is adopted.

[0010] In the present invention, as a fifth solution means related to the boost control device, in the above-described third solution means, when the duty ratio setting unit detects an abnormality in the output voltage sensor that detects the output voltage, the duty ratio setting unit divides the result of the averaging process between the output voltage before the abnormality and the output voltage after the abnormality by the input voltage, thereby setting the duty ratio command value for the upper arm. The means described above is adopted.

[0011] In the present invention, as a sixth solution means related to the boost control device, in the above-described third solution means, when the duty ratio setting unit detects an abnormality in the input voltage sensor that detects the input voltage and the output voltage sensor that detects the output voltage, the duty ratio setting unit divides the result of the averaging process between the input voltage before the abnormality and the input voltage after the abnormality by the result of the averaging process between the output voltage before the abnormality and the output voltage after the abnormality, thereby setting the duty ratio command value for the upper arm. The means described above is adopted.

[0012] In the present invention, as a seventh solution means related to the boost control device, in any of the first to sixth solution means described above, the duty ratio command value for driving the upper arm is set so that the ON / OFF duty ratio of the upper arm switch gradually increases with the passage of time. The means described above is adopted.

[0013] In the present invention, as a solution means related to the boost device, the means adopted is to include a boost control device according to any of the first to seventh solution means and a boost circuit controlled by the boost control device.

Advantages of the Invention

[0014] According to the present invention, it is possible to provide a boost control device and a boost device capable of ensuring higher switching stability of the control mode at the time of abnormality occurrence than in the prior art.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a PCU1 (Power Control Unit) in the present embodiment. As shown in the figure, this PCU1 is provided between a battery P, a motor M, and a generator G, and has, as external connection terminals, a pair of battery terminals E1 and E2 to which the battery P is connected, three motor terminals Fu, Fv, and Fw to which the traveling motor M is connected, and three generator terminals Hu, Hv, and Hw to which the generator G is connected.

[0017] As shown in the figure, the battery P has its positive electrode connected to the positive electrode battery terminal E1 and its negative electrode connected to the negative electrode battery terminal E2. This battery P is a secondary battery such as a lithium-ion battery and performs charging and discharging of DC power via the PCU1.

[0018] The traveling motor M is a three-phase motor and is a load of the driving inverter D2. This traveling motor M has its U-phase input terminal connected to the U-phase motor terminal Fu, its V-phase input terminal connected to the V-phase motor terminal Fv, and its W-phase input terminal connected to the W-phase motor terminal Fw. Such a traveling motor M has its rotating shaft (driving shaft) connected to the wheels of an electric vehicle, and rotates the wheels by applying traveling power to the wheels.

[0019] The generator G is a three-phase generator, with its U-phase output terminal connected to the U-phase generator terminal Hu, its V-phase output terminal connected to the V-phase generator terminal Hv, and its W-phase output terminal connected to the W-phase generator terminal Hw. This generator G is connected to the output shaft of a power source such as an engine mounted on an electric vehicle, and outputs three-phase AC power to the PCU1.

[0020] In this way, the PCU1 that performs power conversion among the battery P, the motor M, and the generator G is mounted on an electric vehicle such as a hybrid vehicle or an electric vehicle, drives the driving motor M which is the power source of the driving force, and charges the battery P with the generated power of the generator G. That is, the PCU1 has a power running function of converting the DC power of the battery P into three-phase AC power and outputting it to the motor M, and a charging function of converting the regenerative power of the motor M which is AC power or / and the generated power of the generator G into DC power and outputting it to the battery P.

[0021] Such a PCU1 includes, as internal components, a buck-boost converter D1, a driving inverter D2, a generating inverter D3, a gate drive circuit D4, and a control circuit D5. Although details will be described later, the buck-boost device E according to this embodiment is composed of, among the components of such a PCU1, a part of the gate drive circuit D4 and the control circuit D5 (buck-boost control function) and the buck-boost converter D1.

[0022] The buck-boost device E has a boosting function of boosting the battery power (primary power) of a predetermined voltage input from the battery P by the buck-boost converter D1 and outputting it as secondary power to the driving inverter D2, and a bucking function of bucking the DC power (secondary power) input from the driving inverter D2 or / and the generating inverter D3 by the buck-boost converter D1 and outputting it to the battery P as charging power (primary power).

[0023] The boosting function of such a buck-boost device E corresponds to the boosting device according to the present invention. Also, the buck-boost converter D1 corresponds to the boosting circuit of the present invention. Further, the above control circuit D5 corresponds to the buck-boost control device according to this embodiment and also corresponds to the boosting control device according to the present invention.

[0024] To describe each component of the PCU1 in more detail, the buck-boost converter D1 is a power circuit called a so-called magnetically coupled interleaved chopper circuit, and as shown in FIG. 1, it includes a first capacitor 2, a transformer 3, four IGBTs (Insulated Gate Bipolar Transistors) 4a to 4d for transformation, a second capacitor 5, a primary voltage sensor 6, a secondary voltage sensor 7, and a current sensor 8.

[0025] This buck-boost converter D1 alternately performs a boosting operation of boosting the DC power input from the battery P via a pair of battery terminals E1 and E2 and outputting it to the driving inverter D2, and a bucking operation of bucking the DC power input from the driving inverter D2 or / and the power generation inverter D3 and outputting it to the battery P via the pair of battery terminals E1 and E2. That is, this buck-boost converter D1 is a power conversion circuit that boosts or bucks DC power between the battery P and the driving inverter D2 or / and the power generation inverter D3 and inputs and outputs it.

[0026] The driving inverter D2 includes three (a plurality of) switching legs (a U-phase driving switching leg, a V-phase driving switching leg, and a W-phase driving switching leg) provided corresponding to the number of phases of the traveling motor M (electric motor). This driving inverter D2 is a power conversion circuit that alternately performs a power running operation and a regeneration operation, and is driven by first to sixth driving gate signals input from the gate driving circuit D4.

[0027] That is, the driving inverter D2 alternately performs a power running operation of converting the DC power input from the buck-boost converter D1 into three-phase AC power and outputting it to the traveling motor M via three motor terminals Fu, Fv, and Fw, and a regeneration operation of converting the three-phase AC power input from the traveling motor M via the three motor terminals Fu, Fv, and Fw into DC power and outputting it to the buck-boost converter D1. Such a driving inverter D2 is a power conversion circuit that mutually converts DC power and three-phase AC power between the buck-boost converter D1 and the traveling motor M.

[0028] The power generation inverter D3 is a power conversion circuit that converts three-phase AC power input from the generator G via three generator terminals Hu, Hv, and Hw into DC power and outputs it to the buck-boost converter D1. That is, this power generation inverter D3 is a power conversion circuit that mutually converts DC power and three-phase AC power between the buck-boost converter D1 and the generator G, and is driven by first to sixth power generation gate signals input from the gate drive circuit D4.

[0029] Here, the buck-boost converter D1 described above will be further described in detail. In the buck-boost converter D1, one end of the first capacitor 2 is connected to the first DC input / output terminal E1 and the transformer 3, and the other end is connected to the second DC input / output terminal E2. Both ends of such a first capacitor 2 are the primary side input / output terminals in the buck-boost converter D1.

[0030] That is, this first capacitor 2 is connected in parallel to the battery P, and removes high-frequency noise that may be included in the DC power (battery power) input from the battery P to the buck-boost converter D1. Also, for the DC power (charging power) input from the transformer 3, this first capacitor 2 smoothes the possible ripple.

[0031] The transformer 3 includes a primary winding 3a and a secondary winding 3b. One end of the primary winding 3a and one end of the secondary winding 3b are connected to the first DC input / output terminal E1 and one end of the first capacitor 2. Also, the other end of the primary winding 3a is connected to the emitter terminal of the first voltage conversion IGBT 4a and the collector terminal of the second voltage conversion IGBT 4b, and the other end of the secondary winding 3b is connected to the emitter terminal of the third voltage conversion IGBT 4c and the collector terminal of the fourth voltage conversion IGBT 4d.

[0032] Such a transformer 3 has a primary winding 3a and a secondary winding 3b that are electromagnetically coupled with a predetermined coupling coefficient k. That is, the primary winding 3a has a predetermined first self-inductance La according to its number of turns and the like, and the secondary winding 3b has a predetermined second self-inductance Lb according to its number of turns and the like. Further, the primary winding 3a and the secondary winding 3b have a mutual inductance M based on the above-described first self-inductance La, second self-inductance Lb, and coupling coefficient k.

[0033] Among the four IGBTs 4a to 4d for transformer, the first IGBT 4a for transformer and the second IGBT 4b for transformer constitute the A-phase transformer switching leg in the buck-boost converter D1. Also, the third IGBT 4c for transformer and the fourth IGBT 4d for transformer constitute the B-phase switching leg in the buck-boost converter D1.

[0034] The first IGBT 4a for transformer is the upper-arm switch in the A-phase transformer switching leg, and the second IGBT 4b for transformer is the lower-arm switch in the A-phase transformer switching leg. Also, the third IGBT 4c for transformer is the upper-arm switch in the B-phase transformer switching leg, and the fourth IGBT 4d for transformer is the lower-arm switch in the B-phase transformer switching leg.

[0035] The collector terminal of the first IGBT 4a for transformer is commonly connected to the collector terminal of the third IGBT 4c for transformer and one end of the second capacitor 5, the emitter terminal is commonly connected to the other end of the primary winding 3a and the collector terminal of the second IGBT 4b for transformer, and the gate terminal is connected to the first output terminal for the buck-boost converter D1 in the gate drive circuit D4. Such a first IGBT 4a for transformer is a semiconductor switching element whose ON / OFF duty ratio is controlled based on the first gate signal for transformer input from the gate drive circuit D4.

[0036] The second IGBT 4b for voltage transformation has its collector terminal commonly connected to the other end of the primary winding 3a and the emitter terminal of the first IGBT 4a for voltage transformation. Its emitter terminal is commonly connected to the emitter terminal of the fourth IGBT 4d for voltage transformation, the other end of the first capacitor 2, and the other end of the second capacitor 5. Its gate terminal is connected to the second output terminal for the buck-boost converter D1 in the gate drive circuit D4. Such a second IGBT 4b for voltage transformation is a semiconductor switching element whose ON / OFF duty ratio is controlled based on the second gate signal for voltage transformation input from the gate drive circuit D4.

[0037] The third IGBT 4c for voltage transformation has its collector terminal commonly connected to the collector terminal of the first IGBT 4a for voltage transformation and one end of the second capacitor 5. Its emitter terminal is commonly connected to the other end of the secondary winding 3b and the collector terminal of the fourth IGBT 4d for voltage transformation. Its gate terminal is connected to the third output terminal for the buck-boost converter D1 in the gate drive circuit D4. Such a third IGBT 4c for voltage transformation is a semiconductor switching element whose ON / OFF duty ratio is controlled based on the third gate signal for voltage transformation input from the gate drive circuit D4.

[0038] The fourth IGBT 4d for voltage transformation has its collector terminal commonly connected to the other end of the secondary winding 3b and the emitter terminal of the third IGBT 4c for voltage transformation. Its emitter terminal is commonly connected to the emitter terminal of the first IGBT 4a for voltage transformation, the other end of the first capacitor 2, and the other end of the second capacitor 5. Its gate terminal is connected to the fourth output terminal for the buck-boost converter D1 in the gate drive circuit D4. Such a fourth IGBT 4d for voltage transformation is a semiconductor switching element whose ON / OFF duty ratio is controlled based on the fourth gate signal for voltage transformation input from the gate drive circuit D4.

[0039] Such first to fourth IGBTs 4a to 4d for transformation each include a freewheeling diode as shown in the figure. That is, for each of these IGBTs, the cathode terminal is connected to the collector terminal, and the anode terminal is connected to the emitter terminal. Such a freewheeling diode can pass a freewheeling current from the anode terminal to the cathode terminal when the IGBT is in the OFF state.

[0040] One end of the second capacitor 5 is connected to the collector terminals of the first IGBT 4a for transformation and the third IGBT 4c for transformation, and the other end is commonly connected to the emitter terminal of the second IGBT 4b for transformation, the emitter terminal of the fourth IGBT 4d for transformation, the other end of the first capacitor 2, and the second DC input / output terminal E2. Both ends of such a second capacitor 5 are the secondary-side input / output terminals in the buck-boost converter D1.

[0041] Such a second capacitor 5 smoothes the ripple that may be included in the DC power (boost power) input from the first and second switching legs. Also, this second capacitor 5 smoothes the ripple that may be included in the DC power (regenerative power) input from the driving inverter D2 and the DC power (charging power) input from the power generation inverter D3.

[0042] The primary voltage sensor 6 is a voltage sensor that detects the primary voltage V1 on the primary side of the buck-boost converter D1, that is, on the battery P side, and outputs the primary voltage V1, which is a state quantity of the buck-boost converter D1, to the control circuit D5. This primary voltage V1 is the input voltage in the boost operation of the buck-boost converter D1. That is, the primary voltage sensor 6 corresponds to the input voltage sensor of the present invention.

[0043] The secondary voltage sensor 7 is a voltage sensor that detects the secondary voltage V2 on the secondary side of the buck-boost converter D1, that is, on the driving inverter D2 side (power generation inverter D3 side), and outputs the secondary voltage V2, which is a state quantity of the buck-boost converter D1, to the control circuit D5. This secondary voltage V2 is the output voltage in the boost operation of the buck-boost converter D1. That is, the secondary voltage sensor 7 corresponds to the output voltage sensor of the present invention.

[0044] The current sensor 8 is a current sensor that detects the total current of the primary current flowing through the primary winding 3a of the transformer 3 and the secondary current flowing through the secondary winding 3b as the reactor current I, and outputs the reactor current I, which is a state quantity of the buck-boost converter D1, to the control circuit D5. This reactor current I corresponds to the active current flowing from the primary side to the secondary side, the regenerative current or the charging current flowing from the secondary side to the primary side in the buck-boost converter D1.

[0045] Subsequently, the gate drive circuit D4 includes a transformer gate signal generation unit 9, a drive gate signal generation unit 10, and a power generation gate signal generation unit 11. This gate drive circuit D4 is a circuit that generates first to fourth transformer gate signals, first to sixth drive gate signals, and first to sixth power generation gate signals based on various Duty command values (transformer Duty command value, drive Duty command value, and power generation Duty command value) input from the control circuit D5.

[0046] The transformer gate signal generation unit 9 corresponds to the buck-boost converter D1, and generates first to fourth transformer gate signals based on the transformer Duty command value and the transformer carrier frequency input from the control circuit D5. This transformer gate signal generation unit 9 corresponds to the drive signal generation unit of the present invention. Among the first to fourth transformer gate signals, the first and third transformer gate signals correspond to the upper arm drive signals of the present invention, and the second and fourth transformer gate signals correspond to the lower arm drive signals of the present invention.

[0047] That is, the transformer gate signal generation unit 9 compares the transformer Duty command value with a carrier wave (triangle wave) having a period corresponding to the transformer carrier frequency, and generates a PWM (Pulse Width Modulation) signal having a repetition frequency (repetition period) and a duty ratio corresponding to the transformer carrier frequency and the transformer Duty command value as the first to fourth transformer gate signals.

[0048] This gate signal generation unit 9 for transformation outputs the first gate signal for transformation to the gate terminal of the first IGBT 4a for transformation, outputs the second gate signal for transformation to the gate terminal of the second IGBT 4b for transformation of the buck-boost converter D1, outputs the third gate signal for transformation to the third IGBT 4c for transformation of the buck-boost converter D1, and outputs the fourth gate signal for transformation to the fourth IGBT 4d for transformation of the buck-boost converter D1.

[0049] The drive gate signal generation unit 10 corresponds to the drive inverter D2, and generates first to sixth drive gate signals based on the drive Duty command value and the drive carrier frequency input from the control circuit D5.

[0050] That is, the drive gate signal generation unit 10 compares the drive Duty command value with a carrier wave (triangle wave) having a period corresponding to the drive carrier frequency, and generates a PWM signal having a repetition frequency (repetition period) and a duty ratio corresponding to the drive carrier frequency and the drive Duty command value as the first to sixth drive gate signals.

[0051] The power generation gate signal generation unit 11 corresponds to the power generation inverter D3, and generates first to sixth power generation gate signals based on the power generation Duty command value and the power generation carrier frequency input from the control circuit D5.

[0052] That is, the power generation gate signal generation unit 11 compares the power generation Duty command value with a carrier wave (triangle wave) having a period corresponding to the power generation carrier frequency, and generates a PWM signal having a repetition frequency (repetition period) and a duty ratio corresponding to the power generation carrier frequency and the power generation Duty command value as the first to sixth power generation gate signals.

[0053] The control circuit D5 controls the boost - buck converter D1, the drive inverter D2, and the power - generation inverter D3 via the gate - drive circuit D4, thereby performing drive control of the traveling motor M and charge control of the battery P. This control circuit D5 outputs various Duty command values (transforming Duty command value, drive Duty command value, and power - generation Duty command value) generated based on a pre - stored control program to the gate - drive circuit D4.

[0054] That is, the control circuit D5 generates a transforming Duty command value, a drive Duty command value, and a power - generation Duty command value based on the voltage detection values (primary voltage V1 and secondary voltage V2) of the primary - voltage sensor 6 and the secondary - voltage sensor 7 provided additionally in the boost - buck converter D1, the current detection value (reactor current I) of the current sensor 8, and the operation information of the electric vehicle input from a host control device (not shown). Note that such a control circuit D5 corresponds to the duty - ratio setting unit of the present invention.

[0055] This control circuit D5 controls the boost - buck converter D1 by outputting the transforming Duty command value to the transforming - gate - signal generation unit 9. Also, the control circuit D5 controls the drive inverter D2 by outputting the drive Duty command value to the drive - gate - signal generation unit 10. Further, the control circuit D5 controls the power - generation inverter D3 by outputting the power - generation Duty command value to the drive - gate - signal generation unit 10.

[0056] Also, this control circuit D5 has a function of detecting an abnormality of the boost - buck converter D1 described above. The control circuit D5 detects an abnormality of the primary - voltage sensor 6, the secondary - voltage sensor 7, and the current sensor 8 based on, for example, the primary voltage V1, the secondary voltage V2, and the reactor current I among the components of the boost - buck converter D1.

[0057] Subsequently, the functional configuration of the boost - buck control device, that is, the control circuit D5 according to the present embodiment will be described in detail with reference to FIG. 2.

[0058] This control circuit D5 is a control component responsible for controlling the buck-boost converter D1. This control circuit D5 controls the transformer gate signal generation unit 9 that drives the buck-boost converter D1, and includes a target value setting unit 12, an input unit 13, a current control unit 14, a voltage control unit 15, a Duty control unit 16, and a carrier frequency setting unit 17 as shown in FIG. 2.

[0059] The target value setting unit 12 is a functional component that sets a control target value for transformation based on the operation amount of the electric vehicle, etc. This control target value for transformation is the target amount of the boost ratio when the buck-boost converter D1 performs a boosting operation or the target amount of the buck ratio when the buck-boost converter D1 performs a bucking operation. The target value setting unit 12 outputs such a control target value X0 for transformation to the current control unit 14. Note that the above boost ratio or buck ratio is the ratio of the primary voltage V1 and the secondary voltage V2 described above.

[0060] The input unit 13 is a signal conversion circuit that samples the primary voltage V1 input from the primary voltage sensor 6, the secondary voltage V2 input from the secondary voltage sensor 7, and the reactor current I, that is, an analog signal input from the current sensor 8 in time series and converts it into a digital signal. This input unit 13 outputs the primary voltage V1, the secondary voltage V2, and the reactor current I, which are digital signals, to the voltage control unit 14 and the carrier frequency setting unit 17, and also outputs the reactor current I, which is a digital signal, to the voltage control unit 15.

[0061] Note that the input unit 13 has a storage function as an additional function to temporarily store the past primary voltage V1, secondary voltage V2, and reactor current I sampled over a certain period. That is, the input unit 13 has a storage capacity to store, for example, dozens of samples of the primary voltage V1, secondary voltage V2, and reactor current I.

[0062] Furthermore, the input unit 13 performs a moving average process or a low-pass filter process (averaging process) on a plurality of past and latest (current) primary voltages V1, secondary voltages V2, and reactor currents I arranged in time series as digital values, thereby calculating estimated values (primary voltage estimated value V1e and secondary voltage estimated value V2e) of the primary voltage V1 and the secondary voltage V2 at the current time point, and has an estimated value calculation function.

[0063] The current control unit 14 is a calculation unit that calculates a current command value X1 based on the transformation control target value X0 input from the target value setting unit 12, and the primary voltage V1, secondary voltage V2, and reactor current I input from the input unit 13. This current control unit 14 outputs the current command value X1 to the voltage control unit 15.

[0064] The voltage control unit 15 is a calculation unit that calculates a voltage command value X2 based on the current command value X1 and the reactor current I. This voltage control unit 15 outputs the voltage command value X2 to the Duty control unit 16. The Duty control unit 16 is a calculation unit that calculates Duty command values X3, X4 indicating the duty ratios of the first to fourth transformation gate signals (PWM signals) based on the voltage command value X2.

[0065] Here, the step-up / down converter D1 described above is a magnetic coupling interleaved chopper circuit including a magnetically coupled primary winding 3a and secondary winding 3b, and an A-phase transformation switching leg and a B-phase switching leg. The A-phase transformation switching leg and the B-phase switching leg are controlled by first and second transformation gate signals and third and fourth transformation gate signals having a phase difference of 180°.

[0066] To correspond to such a step-up / down converter D1, the Duty command values X3, X4 are composed of an A-phase Duty command value X3 and a B-phase Duty command value X4. That is, the A-phase Duty command value X3 is a command value specifying the duty ratios of the first and second transformation gate signals, and the B-phase Duty command value X4 is a command value specifying the duty ratios of the third and fourth transformation gate signals.

[0067] The carrier frequency setting unit 17 is a functional component that sets the repetition frequency (carrier frequency fc) of the first to fourth transformer gate signals based on the primary voltage V1, secondary voltage V2, and reactor current I described above. This carrier frequency fc is the power generation carrier frequency corresponding to the frequency of the carrier wave (triangular wave) used by the transformer gate signal generation unit 9 to generate the first to fourth transformer gate signals, and is a physical quantity that specifies the switching frequency of the first to fourth transformer IGBTs 6a to 6d that constitute the buck-boost converter D1.

[0068] That is, the carrier frequency setting unit 17 sets the carrier frequency fc of the buck-boost converter D1 (magnetic coupling interleaved chopper circuit) based on the primary voltage V1, secondary voltage V2, and reactor current I indicating the operating state of the buck-boost converter D1 (magnetic coupling interleaved chopper circuit).

[0069] Next, the operations of the buck-boost device E and the buck-boost control device (control circuit D5) according to the present embodiment will be described in detail with reference to FIGS. 3 and 4.

[0070] As described above, the primary voltage V1 is input from the primary voltage sensor 6 to the control circuit D5, the secondary voltage V2 is input from the secondary voltage sensor 7, and the reactor current I is constantly input from the current sensor 8. The control circuit D5 sequentially repeats the process (backup operation switching process) that starts after the abnormal diagnosis shown in FIG. 3 is completed (the abnormality is confirmed) for each value of the primary voltage V1, secondary voltage V2, and reactor current I at a predetermined time interval, thereby generating the A-phase Duty command value X3 and the B-phase Duty command value X4 at each time as follows.

[0071] First, the control circuit D5 determines whether an abnormality has occurred in the primary voltage sensor 6, the secondary voltage sensor 7, or / and the current sensor 8 by evaluating whether the values of the primary voltage V1, the secondary voltage V2, and the reactor current I are within a preset normal range (step S1). Then, when no abnormality has occurred in the primary voltage sensor 6, the primary voltage sensor 6, the secondary voltage sensor 7, and the current sensor 8, that is, when the determination in step S1 is "No", the control circuit D5 performs normal control arithmetic processing (step S2).

[0072] That is, the control circuit D5 outputs the A-phase Duty command value X3 and the B-phase Duty command value X4 finally generated by the above-described target value setting unit 12, input unit 13, current control unit 14, voltage control unit 15, Duty control unit 16, and carrier frequency setting unit 17 to the transformer gate signal generation unit 9. Then, the transformer gate signal generation unit 9 generates the first to fourth transformer gate signals based on the A-phase Duty command value X3 and the B-phase Duty command value X4 and outputs them to the buck-boost converter D1.

[0073] As shown in FIG. 4, during the boosting operation of the buck-boost converter D1, the first and second transformer gate signals are pulse signals that repeat high potential and low potential at a constant period so as to synchronously turn on and off the first and second transformer IGBTs 4a and 4b. On the other hand, the third and fourth transformer gate signals are signals in which the first and second transformer gate signals are phase-inverted, and are pulse signals that repeat high potential and low potential at a constant period so as to synchronously turn on and off the third and fourth transformer IGBTs 4c and 4d.

[0074] The buck-boost converter D1 boosts the primary voltage V1 to generate the secondary voltage V2 by turning on and off the first to fourth transformer IGBTs 4a to 4d (boosting switching operation) by such first to fourth transformer gate signals. Then, this secondary voltage V2 is input to the driving inverter D2, converted into three-phase AC power, and input to the motor M. That is, the motor M is normally driven by the cooperation of the buck-boost converter D1 and the driving inverter D2.

[0075] Here, the first and second transformer IGBTs 4a and 4b that constitute the A-phase switching leg are driven by the first and second transformer gate signals, and the phase of these signals is 180° different from the third and fourth transformer gate signals that drive the third and fourth transformer IGBTs 4c and 4d that constitute the B-phase switching leg. Therefore, the first and second transformer IGBTs 4a and 4b and the third and fourth transformer IGBTs 4c and 4d turn on and off with a 180° phase difference.

[0076] As a result, the reactor current of the primary winding 3a connected to the A-phase switching leg (A-phase reactor current Ia) and the reactor current of the secondary winding 3b connected to the B-phase switching leg (B-phase reactor current Ib) have a relationship where the phase of the ripple current is 180° different. This A-phase reactor current Ia flows through the second capacitor 5 via the freewheeling diode provided in the first transformer IGBT 6a, and the B-phase reactor current Ib flows through the second capacitor 5 via the freewheeling diode provided in the third transformer IGBT 6c.

[0077] That is, a combined current of the A-phase reactor current Ia and the B-phase reactor current Ib flows through the second capacitor 5. The amplitude of this combined current is extremely small because the A-phase reactor current Ia and the B-phase reactor current Ib have a phase difference of 180°. In such a buck-boost converter D1 (magnetic coupling interleaved chopper circuit), the output current ripple is significantly reduced compared to a general chopper circuit with a single-phase configuration.

[0078] Regarding the normal operation of the buck-boost device E based on the normal control operation processing in such a control circuit D5, when the determination in step S1 is "Yes", that is, when an abnormality in the primary voltage sensor 6, the secondary voltage sensor 7, or / and the current sensor 8 is detected, the control circuit D5 determines whether this abnormality is a first-time abnormality, that is, an abnormality that has occurred for the first time (step S3).

[0079] That is, when the control circuit D5 detects the occurrence of an abnormality in the primary voltage sensor 6 based on the primary voltage, it determines whether this abnormality in the primary voltage sensor 6 is detected for the first time after the vehicle starts running. Further, when the control circuit D5 detects the occurrence of an abnormality in the secondary voltage sensor 7 based on the secondary voltage, it determines whether this abnormality in the secondary voltage sensor 7 is detected for the first time after the vehicle starts running. Moreover, when the control circuit D5 detects the occurrence of an abnormality in the current sensor 8 based on the reactor current I, it determines whether this abnormality in the current sensor 8 is detected for the first time after the vehicle starts running.

[0080] Then, when the determination in step S3 is "Yes", that is, in the case of the first abnormality, the control circuit D5 fixes the lower arm switches, that is, the second transformer IGBT 4b of the A-phase switching leg and the fourth transformer IGBT 4d of the B-phase switching leg, to the OFF state, and among the A-phase Duty command value X3 and the B-phase Duty command value X4, the A-phase lower arm Duty command value X3 L (lower arm duty ratio command value) and the B-phase lower arm Duty command value X4 L (lower arm duty ratio command value) are set (step S4).

[0081] Subsequently, following step S4 above, for the upper arm switches, that is, the first transformer IGBT 4a of the A-phase switching leg and the third transformer IGBT 4c of the B-phase switching leg, the control circuit D5 sets the A-phase upper arm Duty command value X3 H (upper arm duty ratio command value) and the B-phase upper arm Duty command value X4 H (upper arm duty ratio command value) as follows (step S5).

[0082] That is, the control circuit D5 sets the duty ratio command value for driving the upper arm using the primary voltage estimated value V1e, the secondary voltage estimated value V2e, and the reactor current estimated value Ie calculated by the input unit 13. These primary voltage estimated value V1e, secondary voltage estimated value V2e, and reactor current estimated value Ie are highly reliable values calculated using the primary voltage V1 (input voltage), secondary voltage V2 (output voltage), and reactor current I before the occurrence of an abnormality, that is, the normal primary voltage V1 (input voltage), secondary voltage V2 (output voltage), and reactor current I.

[0083] Here, for example, when an abnormality in the primary voltage sensor 6 is detected, the control circuit D5 selects the primary voltage estimated value V1e among the primary voltage estimated value V1e, secondary voltage estimated value V2e, and reactor current estimated value Ie, and divides the primary voltage estimated value V1e by the secondary voltage V2 to obtain the Duty command value X3 for the A-phase upper arm H and the Duty command value X4 for the B-phase upper arm H and sets them.

[0084] Also, for example, when an abnormality in the secondary voltage sensor 7 is detected, the control circuit D5 selects the secondary voltage estimated value V2e among the primary voltage estimated value V1e, secondary voltage estimated value V2e, and reactor current estimated value Ie, and divides the primary voltage V1 by the secondary voltage estimated value V2e to obtain the Duty command value X3 for the A-phase upper arm H and the Duty command value X4 for the B-phase upper arm H and sets them.

[0085] Furthermore, when an abnormality in both the primary voltage sensor 6 and the secondary voltage sensor 7 is detected, the control circuit D5 selects the primary voltage estimated value V1e and the secondary voltage estimated value V2e among the primary voltage estimated value V1e, secondary voltage estimated value V2e, and reactor current estimated value Ie. Then, the control circuit D5 divides the primary voltage estimated value V1e by the secondary voltage estimated value V2e to obtain the Duty command value X3 for the A-phase upper arm H and the Duty command value X4 for the B-phase upper arm H and sets them.

[0086] On the other hand, when the determination result of step S3 described above is "No", that is, in the case of an abnormality after the second time, the control circuit D5 fixes the lower arm switches (the second transformer IGBT 4b and the fourth transformer IGBT 4d) to the OFF state, and sets the lower arm duty ratio command values (the A-phase lower arm Duty command value X3 L and the B-phase lower arm Duty command value X4 L )(step S6).

[0087] Then, when the process of step S6 is completed, the control circuit D5 evaluates whether the upper arm duty ratio command values (the A-phase upper arm Duty command value X3 H and the B-phase upper arm Duty command value X4 H ) at the time of abnormality are 100% or less (step S7).

[0088] Then, when the determination in step S7 is "Yes", that is, when the upper arm duty ratio command values (the A-phase upper arm Duty command value X3 H and the B-phase upper arm Duty command value X4 H ) are 100% or less, for the upper arm switches (the first transformer IGBT 4a and the third transformer IGBT 4c), the control circuit D5 sets the upper arm duty ratio command values (the A-phase upper arm Duty command value X3 H and the B-phase upper arm Duty command value X4 H ) as follows (step S8).

[0089] That is, the control circuit D5 adds a preset value Δd (Duty increase amount) to the current upper arm duty ratio command value Dn to gradually increase the upper arm duty ratio command values (the A-phase upper arm Duty command value X3 H and the B-phase upper arm Duty command value X4 H ) over time.

[0090] On the other hand, when the determination in step S7 is "No", that is, when the upper arm duty ratio command values (the A-phase upper arm Duty command value X3 H and the B-phase upper arm Duty command value X4H ) reaches 100%, the abnormal diagnosis process is terminated.

[0091] By repeating such an abnormal diagnosis process, the duty ratio command value for the upper arm (Duty command value X3 for the A-phase upper arm H and Duty command value X4 for the B-phase upper arm H ) gradually increases according to the passage of time since the occurrence of the abnormality and finally reaches 100%. As a result, the boosting operation of the buck-boost converter D1 completely stops.

[0092] Here, as shown in FIG. 4, a time difference (time lag) occurs between the time te of occurrence of an abnormality in the primary voltage sensor 6, the secondary voltage sensor 7, or / and the current sensor 8 and the time ts of detection of the abnormality in the control circuit D5. The period from the time te of occurrence of the abnormality to the time ts of detection of the abnormality is a control mode transition period in which the control mode of the control circuit D5 switches from the normal mode to the retreat mode, and is also an operation state transition period in which the operation state of the electric vehicle switches from the normal operation to the retreat operation.

[0093] During this switching period, since the control circuit D5 cannot acquire the normal primary voltage V1, secondary voltage V2, or / and reactor current I, the Duty command value generated by the control circuit D5 lacks normality.

[0094] Then, after the time ts of detection of the abnormality, the control circuit D5 fixes the lower arm switches (IGBT4b for the second transformer and IGBT4d for the fourth transformer) in the OFF state, and sets the duty ratio command value for the lower arm (Duty command value X3 for the A-phase lower arm L and Duty command value X4 for the B-phase lower arm L ). As a result, the buck-boost converter D1 stops the boosting operation.

[0095] Then, the control circuit D5 uses the estimated values (primary voltage estimated value V1e, secondary voltage estimated value V2e, or / and reactor current estimated value Ie) generated based on the detection values before the occurrence of an abnormality in the abnormality sensor (primary voltage sensor 6, secondary voltage sensor 7, or / and current sensor 8) and the detection values of the normal sensor to generate the upper arm duty ratio command values (A-phase upper arm Duty command value X3 H and B-phase upper arm Duty command value X4 H ).

[0096] That is, the control circuit D5 generates the upper arm duty ratio command values (A-phase upper arm Duty command value X3 H and B-phase upper arm Duty command value X4 H ) without directly using the detection values of the abnormality sensor. As a result, the upper arm duty ratio command values (A-phase upper arm Duty command value X3 H and B-phase upper arm Duty command value X4 H ) are set to increase monotonically over time and reach 100%.

[0097] As a result, the output voltage (secondary voltage V2) of the buck-boost converter D1 monotonically decreases and reaches the primary voltage V1 during the evacuation operation (evacuation mode) after the abnormality detection time ts, as shown in FIG. 4. Note that if the detection values of the abnormality sensor are directly used to generate the upper arm duty ratio command values (A-phase upper arm Duty command value X3 H and B-phase upper arm Duty command value X4 H ), when transitioning from the operation state transition period (control mode transition period) to the evacuation operation (evacuation mode), as shown by the dashed-dotted line in FIG. 4, the output voltage (secondary voltage V2) of the buck-boost converter D1 may temporarily increase.

[0098] According to the present embodiment, it is possible to ensure higher switching stability of the control mode when an abnormality occurs in the primary voltage sensor 6, the secondary voltage sensor 7, and / or the current sensor 8 than in the prior art. Therefore, according to the present embodiment, it is possible to improve the running stability of the electric vehicle when an abnormality occurs in the primary voltage sensor 6, the secondary voltage sensor 7, and / or the current sensor 8 than in the prior art.

[0099] Note that the present invention is not limited to the above-described embodiment, and for example, the following modifications can be considered. (1) In the above embodiment, the case where the present invention is applied to the PCU 1 including the buck-boost converter D1, the drive inverter D2, the power generation inverter D3, the gate drive circuit D4, and the control circuit D5 has been described, but the present invention is not limited thereto. The present invention is applicable to, for example, a boosting device including a single boosting circuit, a gate drive circuit that outputs a gate signal to the boosting circuit, and a control circuit that outputs a Duty command value to the gate drive circuit.

[0100] (2) In the above embodiment, the primary voltage estimated value V1e, the secondary voltage estimated value V2e, and the reactor current estimated value Ie are calculated using the primary voltage V1 (input voltage), the secondary voltage V2 (output voltage), and the reactor current I before the occurrence of the abnormality, but the present invention is not limited thereto. When calculating the primary voltage estimated value V1e, the secondary voltage estimated value V2e, and the reactor current estimated value Ie, the primary voltage V1 (input voltage), the secondary voltage V2 (output voltage), and the reactor current I after the occurrence of the abnormality may be added to the primary voltage V1 (input voltage), the secondary voltage V2 (output voltage), and the reactor current I before the occurrence of the abnormality.

[0101] The primary voltage estimated value V1e, the secondary voltage estimated value V2e, and the reactor current estimated value Ie may be obtained by setting the time ratio between the detected values before the occurrence of the abnormality and the detected values after the occurrence of the abnormality so that the influence of the detected values before the occurrence of the abnormality is mainly dominant, and performing a moving average process or a low-pass filter process (averaging process) on the detected values before the occurrence of the abnormality and the detected values after the occurrence of the abnormality.

[0102] (3) In the above embodiment, the occurrence of abnormalities in the primary voltage sensor 6, the secondary voltage sensor 7, and the current sensor 8 is detected, but the present invention is not limited thereto. Only the occurrence of an abnormality in a part of the primary voltage sensor 6, the secondary voltage sensor 7, and the current sensor 8, for example, the primary voltage sensor 6, is detected, and the duty command values X3 H for the upper arm of phase A and H the duty command value X4

[0103] for the upper arm of phase B H are generated using the estimated primary voltage V1e and the secondary voltage V2. H (4) In the above embodiment, the method for generating the duty command value X3 for the upper arm of phase A and

[0104] the duty command value X4 for the upper arm of phase B is changed according to whether the abnormality is the first time or not, but the present invention is not limited thereto. ​​​​​​​​​​​​​​​​​​​​​10 Drive gate signal generation unit 11 Power generation gate signal generation unit 12 Target value setting unit 13 Input unit 14 Current control unit 15 Voltage control unit 16 Duty control unit 17 Carrier frequency setting unit

Claims

1. A boost control device for controlling a boost circuit that generates an output voltage from an input voltage by including at least one switching leg composed of an upper arm switch and a lower arm switch, and setting the ON / OFF duty ratio of the upper arm switch by an upper arm drive signal and setting the ON / OFF duty ratio of the lower arm switch by a lower arm drive signal, a duty ratio setting unit that sets a lower arm duty ratio command value so that the lower arm switch is fixed in the OFF state when detecting the first occurrence of an abnormality, and sets an upper arm duty ratio command value using the input voltage and / or the output voltage before the first occurrence of the abnormality; A boost control device characterized by comprising.

2. The boost control device according to claim 1, wherein the duty ratio setting unit averages the command value of the output voltage before the occurrence of the abnormality and the input voltage after the occurrence of the abnormality, and sets the upper arm duty ratio command value using the result of the averaging process.

3. The boost control device according to claim 1, wherein the duty ratio setting unit averages the input voltage and / or the output voltage before the occurrence of the abnormality and the input voltage and / or the output voltage after the occurrence of the abnormality, and sets the upper arm duty ratio command value using the result of the averaging process.

4. The boost control device according to claim 3, wherein when the duty ratio setting unit detects an abnormality in an input voltage sensor that detects the input voltage, the upper arm duty ratio command value is set by dividing the result of the averaging process of the input voltage before the occurrence of the abnormality and the input voltage after the occurrence of the abnormality by the output voltage.

5. When the duty ratio setting unit detects an abnormality in an output voltage sensor that detects the output voltage, the upper arm duty ratio command value is set by dividing the result of the averaging process of the output voltage before the occurrence of the abnormality and the output voltage after the occurrence of the abnormality by the input voltage. The boost control device according to claim 3, characterized by the above.

6. When the duty ratio setting unit detects an abnormality in the input voltage sensor that detects the input voltage and the output voltage sensor that detects the output voltage, the duty ratio command value for the upper arm is set by dividing the result of the averaging process of the input voltage before the abnormality and the input voltage after the abnormality by the result of the averaging process of the output voltage before the abnormality and the output voltage after the abnormality. The boost control device according to claim 3, characterized in that

7. The boost control device according to any one of claims 1 to 6, characterized in that the duty ratio command value for the upper arm is set so that the ON / OFF duty ratio of the upper arm switch gradually increases with the passage of time.

8. A boost control device according to any one of claims 1 to 7, a boost circuit controlled by the boost control device A boost device, characterized by comprising

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