KR20160069845A - Apparatus and Method for protecting over temperature in converter - Google Patents

Abstract

The present invention relates to an apparatus for protecting the over temperature of a converter. The apparatus for protecting the over temperature of a converter according to an embodiment of the present invention comprises: a battery; the converter receiving an input voltage from the battery and converting the input voltage into an output voltage; a sensor sensing the input voltage and the temperature of each element of the converter; a control unit generating a maximum current limiting value by each voltage in accordance with the input voltage, generating a current limiting rate by each element temperature for the element of the converter, and generating a final current command value representing the final limiting current using the maximum current limiting value by each voltage and the current limiting rate by each element temperature; and an inverter generating the corresponding output current in accordance with the final current command value.

Description

[0001] The present invention relates to an overtemperature protection device for a converter,

The present invention relates to a converter, and more particularly, to an over-temperature protection device and method of a converter that prevents the converter element from being burned due to over-temperature by causing the converter itself to be in a state where it can not occur above a certain temperature.

In general, there are various systems that make up the environmental difference, one of which is a bidirectional converter between the motor that drives the vehicle, the inverter, and the battery that supplies the voltage to the inverter. Therefore, the DC link voltage of the inverter is controlled.

A high-capacity converter (in particular, a bidirectional DC-DC converter) can actively generate an output DC link voltage, thereby improving the efficiency of the entire environmental system.

 High-capacity converters are largely composed of inductors and power semiconductors (for example, IGBTs (Insulated Gate Bipolar Mode Transistors)), which cause copper loss and / or switching losses due to current flow. Such copper loss and / or loss may lead to heat generation of the device, which may result in failure of the device if proper cooling is not achieved

Therefore, logic is applied to limit the output current when an over-current occurs due to an instantaneous load operation in which power consumption is high at a time of over temperature due to abnormality such as a cooling system or at a condition of heavy load condition of the vehicle or more.

According to such a current limiting method, there is a disadvantage that a deviation in current limit occurs when the system is applied to a vehicle and a system which is always exposed to a temperature environment such as low temperature and / or excessive temperature. In addition, since it is constituted only by hardware, there is a disadvantage that it is not easy to lower the degree of freedom of design and to tune the control characteristic factor according to the use of the standard component value.

Alternatively, a software-based current limiting scheme is also possible. This is a method of calculating the difference between the output voltage command and the output voltage, and limiting the difference value within a certain range to generate an output signal.

In the case of the software current limiting method, since the state of the battery and / or the elements is not taken into consideration, there is a disadvantage that a precise current limitation is not performed and the overcurrent is likely to occur.

1. Korean Patent Publication No. 10-2006-0119018 2. Korean Patent Publication No. 10-2014-0078481

It is an object of the present invention to provide an overheat protection device and method for preventing overheating due to overheating by reflecting the state of a battery and / or devices.

An aspect of the present invention provides an overheat protection device for a converter that prevents overheating due to overheating by reflecting the state of a battery and / or devices in order to achieve the above-described object.

The over-

1. An overtemperature protection device for a converter applied to an environmental vehicle, comprising:

A sensor that senses an input voltage from the battery and senses a temperature for each element of the converter; And

A maximum current limit value for each voltage according to the input voltage is generated and a current limit rate for each device temperature is generated for each element of the converter and a final limit current And a control unit for generating a final current command value indicating the final current command value,

The converter generates an input current by determining the ON / OFF state of the switching element among the elements according to the final current command value.

The controller may include: a voltage controller receiving the first sum value between the output voltage command and the output voltage to generate a current command value; An intermediate current command value generator for generating an intermediate current command value using the current command value; And a current controller receiving the second sum value between the intermediate current command value and the device current to generate a final current command value.

The intermediate current command value generator may further include: a maximum current limit value calculator for calculating a maximum current limit value for each battery voltage; A current limiting rate calculation unit for each device temperature to calculate the limiting rates for each device temperature; A limiting numerical value determining unit for determining a limiting numerical value having the highest restriction rate among the current limiting rates for each of the device temperatures; A multiplier for multiplying a maximum current limit value for each battery voltage by a limit value to generate a current limit command range; And a limiter for limiting the current command value to the current limit command range to generate the intermediate current command value.

The calculation of the maximum current limit value or the limiting rates for each device temperature according to the battery voltage may be performed through a predetermined look-up table or a mathematical model.

Each of the above elements may be any one of an inductor and a power semiconductor.

In addition, the power semiconductor may be an IGBT (Insulated Gate Bipolar Mode Transistor).

The converter may be a bidirectional HDC (High-Voltage DC to DC Converter) or a unidirectional step-up or step-down converter (Boost or Buck converter).

In this case, the maximum current limit value per battery voltage may be a lower value as the input voltage from the battery is higher.

On the other hand, another aspect of the present invention provides an output voltage converting method comprising: an output voltage converting step in which a converter receives an input voltage from a battery and converts the input voltage into an output voltage; Sensing the input voltage using a temperature sensor and sensing the temperature of each element of the converter; The control unit generates a maximum current limit value for each voltage according to the input voltage and generates a current limit rate for each element of the converter according to the input voltage and calculates a current limit rate for each element of the converter, A final current command value generating step of generating a final current command value indicating a current; And an input current generation step in which the converter determines an ON / OFF state of a switching element in each element according to the final current command value to generate an input current.

The final current command value generating step may include: a current command value generating step of receiving a first sum value between an output voltage command and the output voltage and generating a current command value; An intermediate current command value generating step of generating an intermediate current command value using the current command value; And a final current command value generation step of receiving a second sum value between the intermediate current command value and the device current and generating a final current command value.

Further, the intermediate current command value step may include: calculating a maximum current limit value for each battery voltage; Calculating limiting rates by device temperature; Determining a limiting value with the highest limiting rate among the current limiting rates by device temperature; Generating a current limit command range by multiplying a maximum current limit value for each battery voltage by a limit value; And generating the intermediate current command value by limiting the current command value to the current limit command range.

According to the effect of the present invention, when the current command itself is limited to a specific value or less, the current is controlled in a controllable manner, so that the heat generation of the device itself can not occur beyond a specific temperature, Loss can be prevented.

Further, another effect of the present invention is that the current can be effectively limited by reflecting the state of the battery and / or the elements.

1 is a block diagram of an over-temperature protection device 110 of a converter according to an embodiment of the present invention.
2 is a detailed block diagram of the converter 120 shown in FIG.
3 is a detailed block diagram of the controller 140 shown in FIG.
4 is a flowchart illustrating a process of performing current limiting to prevent overheating of the converter according to another embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Like reference numerals are used for similar elements in describing each drawing.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. The term "and / or" includes any combination of a plurality of related listed items or any of a plurality of related listed items.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the meaning in the context of the relevant art and are to be construed in an ideal or overly formal sense unless expressly defined in the present application Should not.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout.

1 is a block diagram of an over-temperature protection device 110 of a converter according to an embodiment of the present invention. Referring to FIG. 1, the over-temperature protection device 110 includes a battery 110, a converter 120 that receives an input voltage from the battery 110 and converts the input voltage into an output voltage, A controller 140 for limiting a final current command value indicating a limit current to be provided to the converter 120 to a predetermined range using the input voltage and / or the sensed temperatures, a sensor 140 for sensing temperature of each element, And an inverter 150 for generating a corresponding output current according to the final current command value.

The battery 110 performs charging and / or discharging, and supplies power to the inverter 150. The battery 110 is a 12V rechargeable auxiliary battery, but the present invention is not limited thereto, and may be a high voltage battery through design changes and / or modifications.

Further, the battery 110 is configured such that the battery cells are arranged in series and / or in parallel. The battery cell may be a high voltage battery for an electric vehicle such as a nickel metal battery, a lithium ion battery, a lithium polymer battery, or a full solid battery. Generally, a high-voltage battery is a battery used as a power source for moving an electric vehicle and refers to a high voltage of 100 V or more. However, it is not limited to this, and a low-voltage battery is also possible.

The converter 120 functions to convert an input voltage from the battery 110 into an output voltage. The converter 120 may be a high-voltage DC to DC converter (DCC) or a unidirectional HDC. Of course, in the case of unidirectional HDC, both the voltage controller and the current controller are included in the configuration of the controller 140. [ It may also be a unidirectional step-up or step-down converter (Boost or Buck converter).

The sensor 130 senses an input voltage output from the battery 110, a temperature for each element of the converter 120, an output voltage of the converter 120 and / or the inverter 150, Information. Of course, for such sensing, the sensor 130 includes a current sensor, a voltage sensor, and a temperature sensor. Of course, these sensors may be configured alone, or may be configured inside each converter, inverter, and the like. As the current sensor, a Hall sensor, an optical fiber current sensor, a CT (Current Transformer) type current sensor, and the like can be used.

The controller 140 generates a maximum current limit value for each voltage according to the input voltage output from the battery 110 and generates a current limit rate for each element of the converter 120 according to the device temperature. Also, a final current command value indicating a limiting current to be provided to the inverter 150 is generated by using the maximum current limit value for each voltage and the current limit rate for each element temperature.

The inverter 150 converts the DC voltage from the converter 120 into an AC voltage and provides it to a motor (not shown).

2 is a detailed block diagram of the converter 120 shown in FIG. 2, the converter 120 includes an input stage capacitor 221, an inductor 222, a first power semiconductor 223-1, a second power semiconductor 223-2, an output stage capacitor 224, and the like .

The main heating part of the components of the converter 120 becomes the inductor 222, the first power semiconductor 223-1, and the second power semiconductor 223-2. In particular, an IGBT (Insulated Gate Bipolar Mode Transistor) is used as a switching element in the first and second power semiconductors 223- and 223-2. However, the present invention is not limited thereto, and a field effect transistor (FET) A gate turn-off thyristor (GTO), a TRIAC, a silicon controlled rectifier (SCR), and an integrated circuit (IC) circuit can be used as the semiconductor switching element, the power relay, and the power rectifier diode. In particular, in the case of a semiconductor device, a bipolar or power MOSFET (Metal Oxide Silicon Field Effect Transistor) device can be used. Power MOSFET devices have a double-diffused metal oxide semiconductor (DMOS) structure, unlike conventional MOSFETs, with high-voltage, high-current operation.

In order to prevent the overtemperature state of the inductor 222 and the first and second power semiconductors 223-1 and 223-2, it is necessary to prevent a current of a higher specification from being generated than the initial design value.

Therefore, in one embodiment of the present invention, a limiter at the voltage controller output terminal configured in the controller 140 is used. In addition, the difference between the voltage controller output and the actually measured inductor current is input to the current controller. That is, the output of the voltage controller becomes the current command of the inductor, which is limited to the limiter. This means that the current command is limited within a certain range. If the maximum current of the inductor 222 is limited little by little, the amount of heat generated will be reduced accordingly, so that burn-out of the converter 120 can be prevented. Of course, it is also possible to limit the maximum current of the first power semiconductor 223-1 or the second power semiconductor 223-2 in addition to the inductor 222 to reduce the heat generation amount.

3 is a detailed block diagram of the controller 140 shown in FIG. 3, the control unit 140 includes a voltage controller 320 receiving a first sum value between the output voltage command Vo_cmd and the output voltage Vo to generate a current command value, An intermediate current command value generating unit 330 for generating an intermediate current command value by using the intermediate current command value i_cmd and a device current i, (350), and the like.

The voltage controller 320 and / or the current controller 350 use a proportional-integral (PI) controller.

The voltage controller 320 receives the first sum value generated by adding the output voltage command Vo_cmd and the output voltage Vo from the first adder 310 and generates a current command value.

The intermediate current command value generation unit 330 includes a maximum current limit value calculation unit 331 for calculating a maximum current limit value for each battery voltage, a current limit rate calculation unit 332 for each device temperature to calculate limit rates for each device temperature, A limiting numerical value determining unit 333 for determining a limiting numerical value having the highest limiting rate among the current limiting rates for respective device temperatures, a multiplier (multiplier) 333 for multiplying the maximum current limiting value for each battery voltage by a limiting numerical value, And a limiter 335 for limiting the current command value to the current limit command value and generating the current command value as the intermediate current command value.

The first factor limiting the current is the 'maximum current limit per battery voltage' by the maximum current limit value calculator 331. The maximum current limit value calculation unit 331 is a block for outputting a maximum current limit value corresponding to the input voltage Vin from the battery 110 (FIG. 1).

Due to the characteristics of the bidirectional DC-DC converter, the current flowing through the input terminal (inductor) decreases as the input voltage (battery voltage) increases with the same output power. This is a direct factor affecting the heat generation, so the higher the battery voltage, the more limited the device is by limiting to a lower maximum current command.

The maximum current limit value per battery voltage according to the maximum current limit value calculation unit 331 may be a lookup table having a maximum current per voltage or may be a mathematical model.

The second factor limiting the current is the current limiting rate of each device by temperature by the current limiting rate calculation unit 332 for each device temperature. When the temperature is greatly increased, the current limiting rate (0 to 1) for each temperature is outputted in order to limit the current flowing to the device that may be burned out. When the limiting numerical value determining unit 333 determines the current limiting ratio The limit value (MIN value) that should be restricted is calculated.

The multiplier 334 multiplies the maximum current limit value output from the maximum current limit value calculator 331 by the limited numerical value to generate a range of the current limit command value and inputs it to a limiter 335 which is a current limiting block. The 'current limiting rate of each element temperature by the current limiting factor calculation unit 332 for each device temperature can be implemented in various forms such as a table or a mathematical model set in advance.

 When the current command itself is limited to a specific value or less, the current is limited in a controlled manner, so that the heat generation of the device itself can not occur beyond a specific temperature, thereby preventing the converter from being burned out due to the overtemperature.

The limiter 335 limits the current command value within the current limit command range (-i_ref_max to + i_ref_max) to generate the intermediate current command value (i_cmd). Further, the value (i_ref_max) generated by the multiplier 334 is multiplied by a negative number and a positive number to generate an upper limit value (+ i_ref_max) and a lower limit value (-i_ref_max). Therefore, the range within the upper limit value and the lower limit value is the current limit command range.

The second summer 340 sums the intermediate current command value i_cmd with the element current i and inputs the sum value to the current controller 350. Of course, in one embodiment of the present invention, the device current (i) means the inductor current, but not limited thereto, and it may be the current of the power semiconductor.

The current controller 350 receives the second sum value between the intermediate current command value i_cmd and the element current i to generate a final current command value. This final current command value becomes PWM (Pluse Width Modulation) duty.

4 is a flowchart illustrating a process of performing current limiting to prevent overheating of the converter according to another embodiment of the present invention. Referring to FIG. 4, the converter 120 (FIG. 1) receives an input voltage from the battery 110 (FIG. 1) and calculates a maximum current limit value per battery voltage according to the input voltage (steps S401 and S402).

In addition, the controller 140 (FIG. 1) senses the temperature of each device using the sensor 130 (FIG. 1), and calculates the limiting rates for each device temperature based on the sensed temperature (steps S410 and S420).

In operation S430 and S440, a limiting value having the highest limiting rate among the current limiting rates according to the device temperature is determined, and a current limiting command value is generated by multiplying the maximum current limiting value and the limiting value by the battery voltage.

3) of the control unit 140 receives the first sum value between the output voltage command Vo_cmd and the output voltage Vo to generate a current command value, The current command value is limited to the current limit command range to generate the intermediate current command value i_cmd (step S450).

Thereafter, the current controller 350 of the controller 140 receives the second sum value between the intermediate current command value i_cmd and the actual device current i to generate a final current command value (steps S460 and S470).

100: Over-temperature protection device
110: Battery 120: Converter
130: sensor 140:
150: Inverter
221: input stage capacitor 222: inductor
223-1: First power semiconductor
223-2: Second power semiconductor
224: Output stage capacitor
310: First adder 320: Voltage controller
330: intermediate current command value generating unit
240: second adder 350: current controller

Claims (16)

1. An overtemperature protection device for a converter applied to an environmental vehicle, comprising:
battery;
A sensor that senses an input voltage from the battery and senses a temperature for each element of the converter; And
A maximum current limit value for each voltage according to the input voltage is generated and a current limit rate for each device temperature is generated for each element of the converter and a final limit current And a control unit for generating a final current command value indicating the final current command value,
Wherein the converter generates an input current by determining the ON / OFF state of the switching element among the elements according to the final current command value.
The method according to claim 1,
Wherein,
A voltage controller receiving the first sum value between the output voltage command and the output voltage and generating a current command value;
An intermediate current command value generator for generating an intermediate current command value using the current command value; And
And a current controller receiving the second sum value between the intermediate current command value and the device current to generate a final current command value.
3. The method of claim 2,
Wherein the intermediate current command value generator comprises:
A maximum current limit value calculation unit for calculating a maximum current limit value for each battery voltage;
A current limiting rate calculation unit for each device temperature to calculate the limiting rates for each device temperature;
A limiting numerical value determining unit for determining a limiting numerical value having the highest restriction rate among the current limiting rates for each of the device temperatures;
A multiplier for multiplying a maximum current limit value for each battery voltage by a limit value to generate a current limit command range; And
A limiter for limiting the current command value to the current limit command value to generate the intermediate current command value;
And the over-temperature protection device of the converter.
The method of claim 3,
Wherein the calculation of the maximum current limit value or the limiting rates for each device temperature according to the battery voltage is performed through a preset look-up table or a mathematical model.
The method according to claim 1,
Wherein each of the elements is at least one of an inductor and a power semiconductor.
6. The method of claim 5,
Wherein the power semiconductor is an IGBT (Insulated Gate Bipolar Mode Transistor).
The method according to claim 1,
Wherein the converter is a bi-directional high voltage DC to DC converter or a unidirectional step-up or step-down converter.
The method according to claim 1,
Wherein the maximum current limit value per battery voltage is a lower value as the input voltage from the battery is higher.
An output voltage conversion step of converting the input voltage from the battery to a converter output voltage;
Sensing the input voltage using a temperature sensor and sensing the temperature of each element of the converter;
The control unit generates a maximum current limit value for each voltage according to the input voltage and generates a current limit rate for each element of the converter according to the input voltage and calculates a current limit rate for each element of the converter, A final current command value generating step of generating a final current command value indicating a current; And
An input current generating step of the converter determining an ON / OFF state of a switching element in each element according to the final current command value to generate an input current;
Wherein the over-temperature protection method comprises the steps of:
10. The method of claim 9,
Wherein the final current command value generation step comprises:
A current command value generation step of receiving a first sum value between an output voltage command and the output voltage and generating a current command value;
An intermediate current command value generating step of generating an intermediate current command value using the current command value; And
And a final current command value generation step of receiving a second sum value between the intermediate current command value and the device current and generating a final current command value.
11. The method of claim 10,
Wherein the intermediate current command value step comprises:
Calculating a maximum current limit value per battery voltage;
Calculating limiting rates by device temperature;
Determining a limiting value with the highest limiting rate among the current limiting rates by device temperature;
Generating a current limit command range by multiplying a maximum current limit value for each battery voltage by a limit value; And
Generating the intermediate current command value by limiting the current command value within the current limit command range;
Wherein the over-temperature protection method comprises the steps of:
12. The method of claim 11,
Wherein the calculation of the maximum current limit value or the limiting rates for each device temperature according to the battery voltage is performed through a predetermined look-up table or a mathematical model.
10. The method of claim 9,
Wherein each of the elements is one of an inductor and a power semiconductor.
14. The method of claim 13,
Wherein the power semiconductor is an IGBT (Insulated Gate Bipolar Mode Transistor).
10. The method of claim 9,
Wherein the converter is a bi-directional high voltage DC to DC converter or a unidirectional step-up or step-down converter. 10. The method of claim 9,
Wherein the maximum current limit value per battery voltage is a lower value as the input voltage from the battery is higher.

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