DE-112017007626-B4 - DC/DC converter control device

DE112017007626B4DE 112017007626 B4DE112017007626 B4DE 112017007626B4DE-112017007626-B4

Abstract

DC/DC converter control device, wherein a DC/DC converter (100) comprises an inductor (102) of which one end is connected to a DC power source (1) and which has a circuit (107) configured to include a plurality of semiconductor switching devices (103, 104) and which is connected to another end of the inductor (102), and which converts an input voltage supplied by the DC power source (1) and outputs a voltage after conversion of the input voltage supplied by the DC power source (1) as an output voltage, wherein the DC/DC converter control device comprises: a low-voltage-side voltage sensor (203) for detecting a low-voltage-side voltage which is the input voltage; a low-voltage side voltage detector (403) for outputting a voltage detected by the low-voltage side voltage sensor (203); a first high-voltage-side voltage sensor (201a) for detecting a high-voltage-side voltage which is the output voltage; a first high-voltage-side voltage detector (401) for outputting a voltage detected by the first high-voltage-side voltage sensor (201a); a second high-voltage-side voltage sensor (201b) for detecting the high-voltage-side voltage, which is the output voltage; a second high-voltage-side voltage detector (402) for outputting a voltage detected by the second high-voltage-side voltage sensor (201b); and a fault detection means (301) for detecting a fault of the first high-voltage-side voltage sensor (201a) and a fault of the second high-voltage-side voltage sensor (201b), wherein a switching control is carried out when the plurality of semiconductor switching devices (103, 104) are switched on or off, using: a low-voltage detection voltage (V1) using the low-voltage voltage detector (403), a first high-voltage detection voltage (V2S) using the first high-voltage voltage detector (401), a second high-voltage detection voltage (V2M) by means of the second high-voltage-side voltage detector (402), and wherein, if a fault of the first high-voltage-side voltage sensor (201a) or a fault of the second high-voltage-side voltage sensor (201b) is detected, by a comparison between the first high-voltage-side detection voltage (V2S) or the second high-voltage-side detection voltage (V2M) and a high-voltage-side estimation voltage (V2est), a high-voltage side semiconductor switching device (104), which is connected between one end of the choke (102) and that of the DC/DC converter (100) on its high-voltage side, is switched on, and a fault of a non-faulty one of the first high-voltage side voltage sensor (201a) and the second high-voltage side voltage sensor (201b) is detected, using a non-faulty one of the high-voltage side detection voltage (V2S) and the second high-voltage side detection voltage (V2M).

Inventors

Kazushi Maeda
Masaki Sawamura
Hiroaki TANIHARA
Nobuhiro Kihara
Yuta Komatsu
Takashi Kaneyama

Assignees

MITSUBISHI ELECTRIC CORPORATION

Dates

Publication Date: 20260513
Application Date: 20170609

Claims (5)

DC/DC converter control device, wherein a DC/DC converter (100) comprises an inductor (102) whose end is connected to a DC power source (1) and which has a circuit (107) configured to include a plurality of semiconductor switching devices (103, 104) and which is connected to another end of the inductor (102), and which converts an input voltage supplied by the DC power source (1) and outputs a voltage after conversion of the input voltage as an output voltage, wherein the DC/DC converter control device comprises: a low-voltage-side voltage sensor (203) for detecting a low-voltage-side voltage which is the input voltage; a low-voltage-side voltage detector (403) for outputting a voltage detected by the low-voltage-side voltage sensor (203); a first high-voltage-side voltage sensor (201a) for detecting a high-voltage-side voltage that is the output voltage; a first high-voltage-side voltage detector (401) for outputting a voltage detected by the first high-voltage-side voltage sensor (201a); a second high-voltage-side voltage sensor (201b) for detecting the high-voltage-side voltage that is the output voltage; a second high-voltage-side voltage detector (402) for outputting a voltage detected by the second high-voltage-side voltage sensor (201b); and a fault detection means (301) for detecting a fault in the first high-voltage-side voltage sensor (201a) and a fault in the second high-voltage-side voltage sensor (201b), in which switching control is performed when the plurality of semiconductor switching devices (103, 104) are switched on or off, using: a low-voltage-side detection voltage (V1) by means of the low-voltage-side voltage detector (403), a first high-voltage-side detection voltage (V2S) by means of the first high-voltage-side voltage detector (401), a second high-voltage-side detection voltage (V2M) by means of the second high-voltage-side voltage detector (402), and in which, when a fault in the first high-voltage-side voltage sensor (201a) or a fault in the second high-voltage-side voltage sensor (201b) is detected, a comparison between the first high-voltage detection voltage (V2S) or the second high-voltage detection voltage (V2M) and a high-voltage estimating voltage (V2est), a high-voltage semiconductor switching device (104) connected between one end of the inductor (102) and that of the DC/DC converter (100) on its high-voltage side is switched on, and a fault of a non-faulty one of the first high-voltage-side voltage sensor (201a) and the second high-voltage-side voltage sensor (201b) is detected, using a non-faulty one of the high-voltage-side detection voltage (V2S) and the second high-voltage-side detection voltage (V2M).
DC/DC converter control device according to Claim 1 , wherein the fault of the non-faulty one of the first high-voltage side voltage sensor (201a) and the second high-voltage side voltage sensor (201b) is detected, using the non-faulty one of the first high-voltage side detection voltage (V2S) and the second high-voltage side detection voltage (V2M) and using the low-voltage side detection voltage (V1) output by the low-voltage side voltage detector (403) corresponding to the low-voltage side voltage sensor (203).
DC/DC converter control device according to Claim 1 , wherein, if an induced voltage information of an electric motor (2) is used to indicate an induced voltage (Vtrc, Vgen) consisting of a number of The revolutions (N) of the electric motor (2) connected to the DC/DC converter are calculated, and a drive information to indicate a switching state of the high-voltage side semiconductor switching device (104) has a state in which the high-voltage side semiconductor switching device (104) is fixed in the state of switching off, the high-voltage side estimated voltage (V2est) is estimated according to the information of the induced voltage (Vtrc, Vgen) applied to an electrical discharge resistor (106) of the DC/DC converter, and with a maximum value (Cmax) of the electrical discharge resistor (106) and a maximum value (Rmax) of a high-voltage side capacitor (105) of the DC/DC converter (100).
DC/DC converter control device according to Claim 1 , further comprising an operating information acquisition means (302) for acquiring induced voltage information of an electric motor (2) for displaying an induced voltage (Vtrc, Vgen) of the electric motor (2) connected to the DC/DC converter, wherein, when a difference between a voltage (Vbatt) of the DC power source (1) and an induced voltage (Vtrc, Vgen) of the electric motor (2) is a predetermined value defined in advance, or more, the high-voltage side semiconductor switching device (104) is switched on, a fault of the first high-voltage side voltage sensor (201a) is detected by a comparison between the low-voltage side detection voltage (V1) and the first high-voltage side detection voltage (V2S), and a fault of the second high-voltage side voltage sensor (201b) is detected by a comparison between the low-voltage side detection voltage (V1) and the second high-voltage side Detection voltage (V2M) is detected.
DC/DC converter control device according to Claim 4 , further comprising a high-voltage-side voltage estimator (303) for estimating the high-voltage-side estimated voltage (V2est) from an induced voltage information of the electric motor (2) and from a drive information to indicate a switching state of the high-voltage-side semiconductor switching device (104), wherein the high-voltage-side semiconductor switching device (104) is switched on when the high-voltage-side estimated voltage (V2est) of the DC/DC converter (100) obtained by the high-voltage-side voltage estimator (303) is a predetermined value that is predefined, or less.

Description

TECHNICAL AREA The present invention relates to a control device for a DC/DC converter. STATE OF THE ART A conventional DC/DC converter (electrical power conversion device) consists of a device with terminal groups, a choke and a switching device circuit connected in series, and the device performs a buck-boost conversion of a voltage from a battery to an electric motor. The terminal groups include a first terminal and a second terminal, and the series-connected switching device circuit is a circuit whose first switching device and second switching device are connected in series. As for the pair of switching devices connected in series, one connection point of the first switching device and the second switching device is connected to the first terminal via the choke, and a side opposite the connection point of the first switching device and the second switching device is connected to the second terminal. The first terminal is defined as the low-voltage side and the second terminal as the high-voltage side, so that the conversion of DC voltages between the low-voltage side and the high-voltage side takes place. The DC/DC converter has a calculation tool and an on/off control tool. The calculation tool calculates a value based on the voltage difference between a high-voltage-side voltage instruction value, which is a voltage instruction value on the high-voltage side, and a high-voltage-side voltage detection value, which is a detection value of a high-voltage-side voltage, or on the voltage difference between a low-voltage-side voltage instruction value, which is a voltage instruction value on the low-voltage side, and a low-voltage-side voltage detection value, which is a detection value of a low-voltage-side voltage. The on/off control device detects a switching ratio based on the calculated value and controls the on/off operations of the first switching device and the second switching device based on the switching ratio (e.g. see JP 5 457 559 B2 ). The US 6 978 213 B2 This concerns a voltage conversion system. A battery voltage is amplified in a converter and serves as the input to another converter, which supplies a motor with drive current. A control unit detects the input and output voltages of the converter from the outputs of voltage sensors and controls the switching in the converter according to these detected voltages. If one of the sensors fails, the control unit estimates the voltage that would otherwise have been detected by the failed sensor, based on the switching state in the converter and the voltage detected by the remaining sensor. The DE 11 2016 005 127 T5 This relates to an overboost suppression circuit for a boost converter, which is controlled by a control circuit to boost an input voltage to a prescribed target voltage, wherein the overboost suppression circuit includes: a detection unit that detects an overboost in which a voltage is raised above the prescribed target voltage of the boost converter; and a voltage boost stop unit which, when the overboost is detected by the detection unit, causes the control circuit to stop a voltage boost operation of the boost converter in order to maintain an output voltage of the boost converter at a voltage that is higher than the prescribed target voltage and lower than or equal to a withstand voltage value of a peripheral circuit element, which is a load. The KR 10 2009 062 339 A This relates to a method for diagnosing a defect in a DC-DC converter of an electric vehicle in order to extend the service life of the DC-DC converter and an auxiliary battery in a hybrid/fuel cell vehicle by quickly diagnosing the defect of the DC-DC converter. US 7 425 782 B2 This relates to a voltage conversion device comprising a forward-direction conversion circuit for converting an input voltage from a DC power source into a desired output voltage by adjusting the relative duty cycle (duty ratio) of semiconductor switching elements. The device further comprises a control section that adjusts the relative duty cycle according to at least one target output voltage and one output voltage. The system controls the output voltage so that it approaches the target output voltage. Based on an operating value of the control section, it is assessed whether a fault has occurred. Therefore, it becomes possible to determine whether a fault has occurred without creating a binary system. The JP 2009 213 246 A This concerns a method for accurately detecting a fault in a DC/DC converter, which can perform continuous monitoring and can also deal with an amplifier fluctuation fault or an offset fluctuation fault. SUMMARY OF THE INVENTION [Problems to be solved by the invention] In a conventional DC/DC converter, the state of a high-voltage-side voltage sensor is always detected by the voltage sensor to detect a high-voltage-side voltage, so that a fault or error determination is carried out, regardless of whether a detected value is normal or abnormal. In a case where a voltage se