KR100659308B1 - Revival-Circuit Protection Apparatus In A Motor Drive System - Google Patents

Abstract

The present invention provides a motor, a regenerative circuit for consuming excess regenerative energy generated by operation of the motor as heat using a regenerative resistor, and a power capacity consumed by the regenerative resistor for dissipating regenerative energy as heat in the regenerative resistor. And a regenerative circuit protection unit for stopping the heat dissipation operation by the regenerative resistor if the set reference power capacity is exceeded. The present invention filters the instantaneous power capacity of the regenerative resistor, calculates the effective power consumption consumed by the regenerative resistor, and faithfully protects the regenerative resistor by controlling the motor drive in comparison with the set rated power capacity, and protects the electrical parts (temperature sensor). Programming algorithms to protect regenerative resistors without using them can be implemented by programming, thereby reducing the economic burden.

Description

Regeneration Circuit Protection Device of Motor Drive System {Revival-Circuit Protection Apparatus In A Motor Drive System}

1 is a configuration diagram of a regenerative circuit protection device of a motor drive system according to the present invention.

2 is a diagram illustrating an on / off signal and an on time counting for driving a switch of a regenerative circuit according to the present invention.

3A and 3B are diagrams illustrating a current measuring device of a regenerative resistor and a current time constant of the regenerative resistor according to the present invention.

4A and 4B are views illustrating a temperature measuring device of a regenerative resistor and a temperature time constant of the regenerative resistor according to the present invention.

5A to 5C are diagrams showing instantaneous power capacities corresponding to regenerative energy according to the present invention.

* Description of the symbols for the main functions of the drawings *

10: AC power

20: DC power supply

30: voltage level detection unit

40: regenerative circuit

50: inverter

60: motor

70: regenerative circuit protection unit

80: inverter control unit

Motors are widely used in industrial fields. Generally, when decelerating a motor, regenerative energy is generated that exceeds the energy required to decelerate the motor. The regenerative energy is returned to the DC stage on the input side, causing a voltage rise of the DC stage.

The drive system for driving the motor has a regenerative system that dissipates heat by using a regenerative resistor to consume the regenerative energy of the motor. At this time, in order to prevent the regenerative resistor from overheating due to excessive regenerative energy, the temperature sensor is mounted on the regenerative resistor. When the temperature of the regenerative resistor sensed by the temperature sensor rises above the maximum operating temperature, the driving of the motor is stopped.

However, the existing motor drive system requires economic sensors because the temperature sensor must be installed in the regenerative resistor, and if the regenerative energy is generated continuously, the regenerative resistor is destroyed even if the regenerative resistor temperature is raised to the maximum operating temperature. do.

 SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to control the operation of consuming regenerative energy based on the effective power capacity of the regenerative resistor, thereby regulating the regenerative resistance of the motor drive system. In providing a circuit protection device.

The present invention for achieving the above object, a motor; A regenerative circuit for consuming excess regenerative energy generated by the operation of the motor as heat using a regenerative resistor; And a regenerative circuit protection unit that stops the heat dissipation operation by the regenerative resistor when the power capacity consumed by the regenerative resistor exceeds a set reference power capacity to dissipate regenerative energy as heat in the regenerative resistor.

The regenerative circuit protection unit calculates the instantaneous power capacity by counting time consumed by the regenerative resistor, filters the calculated instantaneous power capacity by using at least one time constant that specifies the regenerative resistance, and filters the instantaneous filtered power. The effective power capacity is calculated from the power capacity, and the calculated effective power capacity is compared with the reference power capacity.

When the regenerative circuit protection unit includes a plurality of time constants to filter the instantaneous power capacity, the plurality of time constants includes a temperature time constant and a current time constant of the regenerative resistor.

The present invention for achieving the above object, a motor; DC power supply for supplying a DC power for driving the motor; A regenerative circuit for consuming excess regenerative energy generated by the operation of the motor as heat using a regenerative resistor; A voltage level detector for outputting a regenerative control signal for determining an operation of consuming heat in the regenerative resistor according to the voltage level of the DC voltage output from the DC power supply unit; And comparing the effective power capacity of the regenerative resistor calculated from the regenerative control signal of the voltage level detector with a predetermined reference power capacity while controlling heat of the regenerative resistor and controlling the operation of the regenerative resistor according to the comparison result. And a regenerative circuit protection unit.

The regenerative circuit further includes a transistor connected to the regenerative resistor to turn on to apply a current to the regenerative resistor and to turn off a current to cut off the current to the regenerative resistor, wherein the voltage level detector is configured as the regenerative control signal. Output an on / off signal for switching the transistor.

The regenerative circuit protection unit receives an on / off signal of the voltage level detector and counts a sampling clock to calculate an instantaneous power capacity and at least one corrected instantaneous power capacity calculated by the instantaneous power calculator. And a filter unit for filtering using a number, and an effective power calculator for calculating an effective power capacity by applying weights to the components filtered by the filter.

The instantaneous power calculation unit calculates the instantaneous power capacity (Pini) by the following equation.

Pini = Vdc * (Vdc / Rr) * (Ta / Ts)

Here, Vdc is the output voltage of the DC power supply, Rr is the resistance value of the regenerative resistor, Ta is the sum of time spent consuming regenerative energy in the regenerative resistor, and Ts is the sampling time.

The filter unit includes first and second filters for filtering the instantaneous power capacity into a current time constant and a temperature time constant, respectively.

The effective power calculator calculates an effective power capacity Peff by the following equation.

Peff = (Ptc1 * Wf) + {Ptc2 * (1-Wf)}

Here, Ptc1 is a component filtered using the temperature time constant (tc1), Ptc2 is a component filtered using the current time constant (tc2), Wf and (1-Wf) is a weight, 0 <Wf <1 to be.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, the present invention is configured by connecting a DC power supply unit 20 and an inverter 50 between an AC power supply 10 and a motor 60.

The DC power supply 20 includes a converter 21 for rectifying three-phase power and a capacitor 22 for smoothing the rectified DC power, and provides the rectified and smoothed DC power to the inverter 50.

The inverter 50 converts DC power into three-phase power under the control of the inverter controller 80, and applies three-phase power to the motor 60 to drive the motor. At this time, the inverter controller 80 controls the inverter 50 to adjust the motor speed.

The voltage level detector 30 and the regenerative circuit 40 are connected between the DC power supply 20 and the inverter 50. The voltage level detector 30 detects an output voltage level of the DC power supply 20 and outputs an on / off pulse signal according to the detected voltage level. The regenerative circuit 40 includes a regenerative resistor 41, a protection diode 42, and a transistor 43. The base end of the transistor 43 is connected to the output end of the voltage level detector 30. The transistor 43 is turned on when the on signal is input so that heat dissipation for the consumption of regenerative energy is made in the regenerative resistor 41, and when the off signal is input, the transistor 43 is turned off so that heat dissipation occurs in the regenerative resistor 41. Do not

When the motor 60 is decelerated, regenerative energy exceeding the energy required for the motor deceleration is generated. The voltage level of the output side of the DC power supply 20 is converted according to the amount of regenerative energy, and the voltage level detector 30 applies the on / off pulse signal to the transistor 43 of the regenerative circuit 40 according to the voltage level. Thus, heat dissipation is made in the regenerative resistor 451.

When excessive regenerative energy is generated, a phenomenon that cannot be handled by heat dissipation only in the regenerative resistor 41 occurs, and if left unchecked, the regenerative resistor 41 is destroyed as the operation of dissipating heat from the regenerative resistor 41 is excessively continued. Can be.

The present invention includes a regenerative circuit protection unit 70 for preventing destruction of the regenerative resistor 41 due to excessive regenerative energy. The regenerative circuit protection unit 70 includes an instantaneous power calculation unit 71, a first filter 72, a second filter 73, an effective power calculation unit 74, and a comparison unit 75.

The instantaneous power calculator 71 calculates the instantaneous power capacity of the regenerative resistor by using the on / off signal of the voltage level detector 30 and counting the sampling clock. As shown in FIG. 2, during the sampling period Ts, the ON / OFF signals are accumulated at the ON times T1, T2, T3, and T4, and the instantaneous power capacity Pini is calculated by the following equation.

Pini = Vdc * (Vdc / Rr) * (T1 + T2 + T3 + T4) / Ts

Here, Vdc is the output voltage of the DC power supply, Rr is the resistance value of the regenerative resistor, (T1 + T2 + T3 + T4) is the sum of the time to consume the regenerative energy in the regenerative resistor, Ts is the sampling time, for example Set within the range of 0.1-2 seconds.

The first and second filters 72 and 73 filter and output the instantaneous power capacity calculated by the instantaneous power calculator 71 using the respective time constants.

The first filter 72 filters the instantaneous power capacity by using the current time constant, and checks the change of the instantaneous power capacity for a relatively short time. As shown in FIG. 3A, the current meter 94 is connected in series between the variable DC power supply 91 and the regenerative resistor 92, and the DC power supply corresponding to the power capacity significantly higher than the rated power capacity of the regenerative resistor is variable. The current is measured by the current meter 94 while the DC power supply 91 is applied to the regenerative resistor 92. The current measured by the current meter 94 maintains the maximum current Ia as shown in FIG. 3B and reaches a current time constant Tc2, whereby the measured current becomes zero.

The second filter 73 filters the instantaneous power capacity by using the temperature time constant, and checks the change of the instantaneous power capacity for a relatively long time. As shown in Fig. 4A, the variable DC power supply 91 and the regenerative resistor 92 are connected in series, and a temperature measuring instrument 93 for measuring the temperature is provided at the regenerative resistor. The temperature is measured by the temperature measuring device 93 while the DC power supply corresponding to the rated power capacity of the regenerative resistor is applied to the regenerative resistor 92 from the variable DC power supply 91. The temperature measured by the temperature measuring device 93 increases as shown in FIG. 4B and reaches a maximum temperature Ta when the temperature time constant Tc1 is reached.

The effective power calculator 74 calculates the effective power capacity Peff by applying weights to the components filtered by the first and second filters 72 and 73, respectively.

Peff = (Ptc1 * Wf) + {Ptc2 * (1-Wf)}

Here, Ptc1 is a component filtered using the temperature time constant (tc1), Ptc2 is a component filtered using the current time constant (tc2), Wf and (1-Wf) is a weight, 0 <Wf <1 to be.

The comparison unit 75 compares the effective power capacity calculated by the effective power capacity calculation unit 74 with the set reference power capacity P1, and when the effective power capacity exceeds the reference power capacity P1 as a result of the comparison, the regeneration is performed. In order to protect the resistor 41, a protection control signal is output to the inverter controller 80.

The inverter controller 80 controls the inverter 50 to stop driving of the motor when the protection control unit 80 is provided from the comparator 75 to cut off the power applied to the motor 60.

Referring to FIG. 5A, when the regenerative energy is small and can adequately handle heat dissipation in the regenerative resistor 41, the current is small when the frequency of the regenerative resistor's power capacity (bar pulse) exceeds the rated power capacity P1 is small. The instantaneous power capacity (thick solid line) filtered by the time constant tc2 is smaller than the rated power capacity.

Referring to FIG. 5B, when the regenerative energy is intensively generated, the instantaneous power capacity filtered by the current time constant tc2 when the frequency at which the power capacity (bar pulse) of the regenerative resistance exceeds the rated power capacity P1 increases. (Thick solid line) also exceeds the rated power capacity P1.

Referring to FIG. 5C, when the regenerative energy is not large within a short time but occurs over a long time, the instantaneous power capacity filtered using the current time constant in a short section is filtered using the temperature time constant even if it falls within the rated power capacity. The power capacity exceeds the rated power capacity.

In this embodiment, the effective power capacity is calculated in consideration of both the instantaneous power capacity filtered using the current time constant and the instantaneous power capacity filtered using the temperature time constant.

Meanwhile, as another embodiment, a method of controlling the inverter according to the comparison result by comparing the instantaneous power capacity filtered using only one of the current time constant and the temperature time constant with the rated power capacity may be applied.

The operation according to the present invention having the above configuration will be described.

First, the inverter controller 80 controls the inverter 50 to drive the motor 60.

Regenerative energy is generated by the deceleration operation of the motor, and the output voltage level of the DC power supply 20 is changed. At this time, the voltage level detector 30 applies the on / off signal to the base terminal of the transistor 43 according to the detected voltage level so that heat is dissipated in the regenerative resistor 41.

While the regenerative resistor 41 dissipates the regenerative energy as heat, the regenerative circuit protection unit 70 calculates the instantaneous power capacity from the on / off signal of the voltage level detector 30, and converts the calculated instantaneous Pole capacity into a current time constant. After filtering by using the temperature time constant, the effective component is calculated by applying weights to the filtered components, and the calculated effective power capacity is compared with the set reference power capacity. According to the comparison result, the inverter is controlled to control the motor drive to faithfully protect the regenerative resistor.

As described above, according to the present invention, the instantaneous power capacity of the regenerative resistor is filtered to calculate the effective power capacity consumed by the regenerative resistor in a system that consumes the regenerative energy of the motor as a heat using the regenerative resistor, and compares with the set rated power capacity. By regulating motor drive, the regenerative resistor is protected. The present invention can implement an algorithm for protecting the regenerative resistor without programming by using an electric component (temperature sensor), thereby reducing the economic burden.

Claims (9)

motor; A regenerative circuit for consuming excess regenerative energy generated by the operation of the motor as heat using a regenerative resistor; And And a regenerative circuit protection unit for stopping the heat dissipation operation by the regenerative resistor when the power capacity consumed by the regenerative resistor exceeds a set reference power capacity. 2. The instantaneous power capacity of claim 1, wherein the regenerative circuit protection unit calculates an instantaneous power capacity by counting a time consuming heat in the regenerative resistor, and calculates an instantaneous power capacity calculated using at least one time constant that specifies the regenerative resistance. A regenerative circuit protection device of a motor drive system that filters, calculates an effective power capacity from the filtered instantaneous power capacity, and compares the calculated effective power capacity with the reference power capacity. The motor drive system of claim 2, wherein when the regenerative circuit protection unit includes a plurality of time constants for filtering the instantaneous power capacity, the plurality of time constants includes a temperature time constant and a current time constant of the regenerative resistor. Regenerative circuit protection device. motor; DC power supply for supplying a DC power for driving the motor; A regenerative circuit for consuming excess regenerative energy generated by the operation of the motor as heat using a regenerative resistor; A voltage level detector for outputting a regenerative control signal for determining an operation of consuming heat in the regenerative resistor according to the voltage level of the DC voltage output from the DC power supply unit; And While the regenerative resistor consumes heat, the effective power capacity of the regenerative resistor calculated from the regenerative control signal of the voltage level detection unit and the set reference power capacity are compared, and regenerative for controlling the operation of the regenerative resistor according to the comparison result. Regenerative circuit protection device for a motor drive system including a circuit protection part. The regenerative circuit of claim 4, wherein the regenerative circuit further comprises a transistor connected to the regenerative resistor to turn on to apply a current to the regenerative resistor and to turn off the regenerative resistor to cut off a current to the regenerative resistor. And a regenerative circuit protection device for a motor drive system for outputting an on / off signal for switching the transistor with the regenerative control signal. The instantaneous power calculation unit of claim 5, wherein the regenerative circuit protection unit receives an on / off signal of the voltage level detection unit and counts a sampling clock to calculate an instantaneous power capacity and an instantaneous power calculated by the instantaneous power calculation unit. And a filter unit for filtering the capacity by using at least one time constant, and an effective power calculation unit for calculating an effective power capacity by applying weights to the components filtered by the filter. The regenerative circuit protection device of claim 6, wherein the instantaneous power calculation unit calculates an instantaneous power capacity (Pini) by the following equation. Pini = Vdc * (Vdc / Rr) * (Ta / Ts) Here, Vdc is the output voltage of the DC power supply, Rr is the resistance value of the regenerative resistor, Ta is the sum of time spent consuming regenerative energy in the regenerative resistor, and Ts is the sampling time. The regenerative circuit protection device of claim 6, wherein the filter unit comprises first and second filters for filtering the instantaneous power capacity into a current time constant and a temperature time constant, respectively. The regenerative circuit protection device of claim 8, wherein the effective power calculating unit calculates an effective power capacity Peff by the following equation. Peff = (Ptc1 * Wf) + {Ptc2 * (1-Wf)} Here, Ptc1 is a component filtered using the temperature time constant (tc1), Ptc2 is a component filtered using the current time constant (tc2), Wf and (1-Wf) is a weight, 0 <Wf <1 to be.

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