RU2808867C1 - Voltage converter for hydrogen power supply system for vehicle - Google Patents

Abstract

FIELD: power supply system.

SUBSTANCE: voltage converter for a hydrogen power supply system for a vehicle. The converter consists of: housing, controller, load switch, precharge resistor, reactor, current sensor, IGBT module, buffer capacity, fuse and diodes. A current sensor and a diode are connected to the reactor output. A buffer capacity at the output and a diode are connected to the IGBT module. The current sensor is used to monitor the output voltage. A fuse link is installed before the output of the voltage converter as a safety device. The voltage converter controller is connected to a control system formed by control boards. Information from the fuel cells is collected on the main control board. An IGBT driver is connected to the voltage converter controller, with the help of which the IGBT module of the boost DC/DC voltage converter is controlled.

EFFECT: powering the vehicle systems while simultaneously charging the battery is achieved.

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Description

Field of technology to which the invention relates

The invention relates to the field of electrical engineering, namely to DC voltage converters that convert the output voltage of a power supply system based on hydrogen-air fuel cells to the level of a high-voltage circuit of an electric vehicle and control the process of operation of the power supply system of a highly automated vehicle.

State of the art

A large number of types of energy converters for different applications are known from the prior art.

A voltage inverter is known (RU 2675726 C1, B60L 1/00, published December 24, 2018), which contains a choke and a control system, two converter cells connected in series with the choke. The converter cells are made according to a two-stage circuit: the first stage is made according to the circuit of a three-level step-up voltage regulator containing two power switches, two diodes, two capacitors forming a capacitive voltage divider, and the second stage is a half-bridge resonant converter, where a pair of series-connected switches is used as power switches semiconductor switches, the load of half-bridge resonant converters is the primary windings of one common transformer, the output windings of the transformer are loaded onto rectifiers, the outputs of which are connected in parallel.

The disadvantages of the described technical solution are that the power section contains a large number of semiconductor diodes and transistors, as well as winding products, which in turn worsens the final efficiency factor (COP) and the weight and size parameters of the device. Another disadvantage is the lack of input current meters, which are necessary for monitoring and controlling electrochemical processes in hydrogen-air fuel cells, which, in turn, narrows the scope of application of this device.

The invention “Voltage converter with key protection” (RU 2549526 C2, G05F 1/00, published on April 27, 2015) is known, designed to provide electricity to various loads and operating from a constant voltage source, containing a control device to increase the security of the device in various accidents. The converter contains a boost regulator based on two switches and two diodes, an input voltage sensor, an input current sensor, a contactor, an input switch, to the power terminals of which a resistor, a capacitor and a transformer winding in the diagonal of the DC/DC converter are connected, a voltage sensor at the output of the boost regulator.

The disadvantages of the described technical solution are: the presence of two conversion stages to ensure galvanic isolation of input and output circuits, as well as a large number of semiconductor devices and passive components to ensure the required switching sequence of the circuit to ensure the intended level of protection of power transistors. These features cause the complication of the control system and the deterioration of the weight and size characteristics and efficiency of the device.

A static voltage converter is known (RU 2762338 C1, H02M 3/337, published 12/20/2021), containing a capacitor at the input with a choke connected to it, forming a DC region; Two three-level boost converters connected in series, each loaded onto its own half-bridge voltage inverter, are connected to the inductor output. Each of these boost converters and the voltage inverter connected to it are made of IGBT modules and power capacitors. Between the midpoint of the power capacitors of the step-up converter and the midpoint of the power switches of the voltage inverter connected to it, a resonant capacitor, a resonant inductor and the primary winding of a common high-voltage power transformer are located in series, forming a series resonant circuit. The control system provides control signals either to the IGBT modules of the boost converter or to the power switches of the half-bridge voltage inverter, depending on the operating mode.

The disadvantages of the described technical solution are: the presence of several conversion stages to ensure galvanic isolation of input and output circuits and to ensure reversibility of the conversion, as well as a large number of semiconductor devices and winding elements, which worsens the weight and size indicators and efficiency. Another disadvantage is the lack of a control system for monitoring and regulating the voltage obtained from hydrogen-air fuel cells, which, in turn, narrows the scope of application of this device.

Disclosure of the invention

The problem that the proposed technical solution solves is the creation of a DC/DC voltage converter with a control system and a power of 5 kW to increase the output voltage of a hydrogen power supply system (HES) as part of a highly automated vehicle (HAV).

The technical result of the claimed invention is the conversion of the output voltage of the hydrogen power supply system into a high constant voltage of the on-board network, which allows you to consume energy for the needs of the VATS and at the same time increase the charge level of the battery.

The specified technical result is achieved using the claimed voltage converter for the hydrogen power supply system of a vehicle, consisting of a housing that contains a load switch with a precharge resistor and a choke connected to it, forming a DC link, while a current sensor and a diode are connected to the output of the choke, which are integral part of the IGBT module, and a buffer capacitance at the output and a diode, which make up the output stage of the converter, and a current sensor for monitoring the output voltage are connected to the IGBT module, in addition, a fuse-link is installed before the output of the voltage converter as a safety device for breaking the circuit if necessary, the voltage converter controller has a connection to a control system formed by control boards of at least two fuel cells, information from which is collected on the main control board of the hydrogen-air fuel cell, as well as communication with an external control system for data exchange In addition, an IGBT driver is connected to the voltage converter controller, with the help of which the IGBT module of the boost DC/DC voltage converter is controlled.

Preferably, a battery (the energy of which is used for the needs of the VATS) is connected to the voltage converter for use in a highly automated vehicle.

The technical solution used in this device is implemented due to the presence of an automated control system that allows you to perform the following functions: measuring current and voltage at the input and output of the voltage converter, regulating the inductor current, maintaining a given voltage value at the output of the converter, protective shutdown of the transistor when voltages are exceeded or currents of permissible values, regulation of the current consumed from the hydrogen power supply system according to an established command, data exchange, receiving and issuing discrete signals for interaction with the external control system and control boards of fuel cells as part of the SES.

Brief description of drawings

Figure 1 shows an electrical diagram of the structure of the source of its own needs, where:

1. SES control system

2. TE battery

3. Input load switch

4. Precharge resistor

5. Buffer capacity at the inlet

6. Voltage sensor

7. Current sensor

8. Throttle

9. Boost converter

10. Reverse current limiting diode

11. Output buffer capacity

12. Fuse link

13. Voltage converter controller

Figure 2 shows a functional diagram of the structure of a source of own needs, where:

1. SES control system

2. TE battery

3. Input load switch

4. Precharge resistor

5. Buffer capacity at the inlet

6. Voltage sensor

7. Current sensor

8. Throttle

9. Boost converter

10. Reverse current limiting diode

11. Output buffer capacity

12. Fuse link

13. Voltage converter controller

14. IGBT module

15. IGBT driver

16. Reverse parallel diode of IGBT transistor

17. Converter output diode

The DC/DC voltage converter has a housing in which an input load switch (3) with a precharge resistor (4) and a choke (8) connected to it are located, forming a DC link. To accumulate energy, a buffer capacitance is installed at the input (5), and the voltage value is monitored using a voltage sensor (6). A current sensor (7) and an IGBT transistor of a boost converter (9) and a diode are connected to the output of the inductor (8) to provide an alternative path for current flow during the power delivery cycle to the load (10), forming an IGBT module (14). A buffer capacitance at the output (11) and a sensor (6) for monitoring the output voltage are connected to the IGBT module (14). The reverse-parallel diode of the IGBT transistor and the transistor itself do not participate in energy conversion (16), and the output diode (17) performs the separating function of the load and the output of the boost stage. A fuse link (12) is installed before the output of the voltage converter as a safety device to open the circuit if necessary.

The voltage converter controller (13) has a connection to the SES control system (1), formed by control boards for each fuel cell, information from which is collected on the main control board of the fuel cell, and communication with an external control system for data exchange via the CAN/RS-485 interface ( state of hydrogen-air fuel cells, voltage converter, transmission of commands to turn fuel cells on and off). The IGBT module (14) of the boost converter is controlled using the IGBT driver (15) also connected to the voltage converter controller (13). To compensate for the lack of electricity, there is a connection of the FC battery (2) to a voltage converter, while the batteries are controlled by the SES control system (1).

Carrying out the invention

When 24 V power is supplied to the voltage converter, the control system is initialized and the device is in the “POWERUP” mode. In this mode, the voltage converter waits for communication with the hydrogen-air fuel cells that are part of the power supply system, the data comes from the main control board (MCP) located on the first fuel cell, the data contains combined information about the five fuel cells. If there is a connection with the SES, the voltage converter goes into the “STANDBY” mode, in which it waits for a start command from the control board (BMS) of the traction battery (TAB).

When a “READY TO CHARGE” command is received from the BMS to start, if there are no errors, the voltage converter sends a command to turn on each fuel cell and goes into STARTUP mode. In this mode, a signal from the fuel cell about a successful start is expected for a maximum of 45 seconds, each of the fuel cells is activated and emergency conditions are monitored; in the absence of accidents, the control boards transmit the “active” signal to the converter. After receiving it and finishing charging the input capacitor of the voltage converter, the relay that shunts the input charging resistor is closed and switches to the “READY” mode.

If there are no errors and there is a charge enable signal from the BMS, the voltage converter sends a signal to the power section and begins to work as a current regulator. At the initial stage, the device switches to the “CHARGING_START” mode, in which, over 60 seconds, it smoothly linearly increases the value of the current consumed from the fuel cells, starting from 5 A. After this, the “CHARGING” mode is set in the device.

The constant current algorithm strives to achieve a value of 30 A if there are no limiting factors. A slow proportional-integral controller (PI controller) is used to maintain the current consumption. When operating the PI controller, voltage limits are used. An additional algorithm has been implemented that compares the minimum among the five voltages of fuel cells and the normal voltage of fuel cells equal to 32.5 V. If the minimum voltage among the elements is more than 32.5 V, the converter smoothly increases the value of the current consumed, if less, it decreases. In this case, the upper limit of the consumed current corresponds to the external setting (from the point of view of the control system) of the consumed current and is in the range of 5...30 A.

If, during operation of the current regulator, at least one of the fuel cell voltages decreases to the limit level of 30 V and does not exceed it within 5 seconds, the voltage converter carries out an emergency stop. In addition, an emergency stop is carried out in the event of any fuel cell error that has not been reset within 5 seconds.

The initiator of stopping the device can be the BMS or the SES control system (a similar CAN protocol is transmitted via the RS-485 interface). Stopping algorithm:

1) The signal to operate the power unit is turned off

2) A signal is sent to turn off the fuel cells

3) The relay that shunts the charging resistor opens

If an emergency stop was carried out due to one of the errors, after five seconds the voltage converter tries to restart: it resets the error, goes into the “WAIT” standby mode for 10 seconds, during which it checks for the absence of new errors, after which, if permission is available from BMS, launches. If errors occur again, the stop and restart algorithm is repeated again until three unsuccessful attempts are made.

Thus, the described device is used as a DC/DC converter of the output voltage of a power supply system based on hydrogen-air fuel cells (in the range from 120 to 320 V) into a high constant voltage of the on-board VATS network, equal to the voltage of the traction battery (from 330 to 380 V ).

The claimed technical solution meets the requirement of industrial applicability and can be implemented on any ground-based unmanned highly automated vehicles.

Claims (1)

A voltage converter for a hydrogen vehicle power supply system, consisting of a housing containing a load switch with a precharge resistor and a choke connected to it, forming a DC link, while a current sensor and a diode are connected to the output of the choke, which are an integral part of the IGBT module, and with An IGBT module connects a buffer capacitor at the output and a diode, which make up the output stage of the converter, and a current sensor to monitor the output voltage, in addition, a fuse-link is installed before the output of the voltage converter as a safety device to open the circuit if necessary, while the voltage converter controller has a connection to the control system formed by the control boards of at least two fuel cells, information from which is collected on the main control board of the hydrogen-air fuel cell, as well as communication with an external control system for data exchange; in addition, a driver is connected to the voltage converter controller IGBT, with which the IGBT module of the boost DC/DC voltage converter is controlled.