CN213661451U - Soft start circuit of frequency converter and frequency converter - Google Patents
Soft start circuit of frequency converter and frequency converter Download PDFInfo
- Publication number
- CN213661451U CN213661451U CN202022806211.8U CN202022806211U CN213661451U CN 213661451 U CN213661451 U CN 213661451U CN 202022806211 U CN202022806211 U CN 202022806211U CN 213661451 U CN213661451 U CN 213661451U
- Authority
- CN
- China
- Prior art keywords
- resistor
- electrolytic capacitor
- frequency converter
- relay
- start circuit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Rectifiers (AREA)
Abstract
The utility model discloses a soft start circuit and converter of converter, the converter includes the rectification unit and connects the filtering energy storage unit at the rectification unit output, the soft start circuit includes microcontroller, starting resistor and relay; one end of a starting resistor is connected to one end of a filtering energy storage unit, which is connected with a first electrolytic capacitor and a second electrolytic capacitor, and the other end of the starting resistor is connected to a zero line connected with the input of the frequency converter; the input loop of the relay is connected with the microcontroller, and the working state of the relay is controlled by the microcontroller; the output loop of the relay is connected with the starting resistor in parallel. The utility model discloses the soft start circuit of converter has with low costs, small and easy integrated advantage on the mainboard to all kinds of rectification application circuit to taking the zero line all are suitable for.
Description
Technical Field
The utility model relates to a converter, in particular to soft start circuit and converter of converter.
Background
The frequency converter is an electric control device which applies a frequency conversion technology and a microelectronic technology and controls an alternating current motor by changing the frequency mode of a working power supply of the motor.
The frequency converter mainly comprises a rectification unit (alternating current to direct current), an energy storage filtering unit, an inversion unit (direct current to alternating current), a driving unit, a detection unit and the like. The frequency converter adjusts the voltage and frequency of an output power supply by switching on and off an internal IGBT, provides the required power supply voltage according to the actual requirement of the motor, and further achieves the purposes of energy saving and speed regulation. With the continuous improvement of the industrial automation degree, the frequency converter is also widely applied.
The energy storage filtering unit is mainly composed of a large-capacity electrolytic capacitor, and because the initial state of the capacitor is equivalent to short circuit, when the input side of the frequency converter is electrified, if rectified voltage is added to the electrolytic capacitor without any treatment, instant large charging current can be caused, impact can be caused to a rectifying loop of the frequency converter, the service life of the electrolytic capacitor is shortened, and even the danger of explosion can be caused. Therefore, the frequency converter must be provided with a protection circuit, which slowly increases the voltage across the electrolytic capacitor at the moment of power-on to avoid the above-mentioned fault, which is a soft start circuit.
In the existing frequency converter circuit structure, a soft start circuit is basically arranged after three-phase rectification, and a large contactor and a thermistor or a cement charging resistor are needed to serve as a soft start switch because the rectified bus voltage is high; in addition, as the input power increases, the soft start contactor and the resistor need to be increased proportionally, and the contactor cannot be integrated on a board when the cost is high and the power is high, so that the assembly and the space size are influenced.
SUMMERY OF THE UTILITY MODEL
The utility model discloses a first aim at overcomes prior art's shortcoming and not enough, provides a soft start circuit of converter, and this soft start circuit has with low costs, small and easy integrated advantage on the mainboard to all kinds of rectification application circuits to taking the zero line all are suitable for.
A second object of the present invention is to provide a frequency converter.
The first purpose of the utility model is realized through the following technical scheme: a soft start circuit of a frequency converter comprises a rectifying unit and a filtering energy storage unit connected to the output end of the rectifying unit, wherein the soft start circuit comprises a microcontroller, a start resistor and a relay;
one end of the starting resistor is connected to one end of the filtering energy storage unit, which is connected with the first electrolytic capacitor and the second electrolytic capacitor, and the other end of the starting resistor is connected to a zero line connected with the input of the frequency converter;
the input loop of the relay is connected with the microcontroller, and the working state of the relay is controlled by the microcontroller;
the output loop of the relay is connected with the starting resistor in parallel.
Preferably, the device further comprises a diode; the diode sets up on the circuit that rectifier unit output positive terminal and filtering energy storage unit first electrolytic capacitor are connected, specifically does: the anode of the diode is connected with the output positive end of the rectifying unit, and the cathode of the diode is connected with the first electrolytic capacitor in the filtering energy storage unit.
Preferably, in the relay input loop, one input end is connected to an IO port of the microcontroller through a resistor, and the other input end is grounded; or in the relay input loop, one input end is connected to an IO port of the microcontroller, and the other input end is grounded through a resistor.
Preferably, in the relay output circuit, one end of the starting resistor is connected with the movable contact of the relay, and the other end of the starting resistor is connected with a normally open stationary contact or a normally closed stationary contact of the relay.
Preferably, the starting resistance is 100 Ω to 200 Ω.
Preferably, the microcontroller is a single chip microcomputer.
The second purpose of the utility model is realized by the following technical scheme: a frequency converter comprising the soft start circuit according to the first aspect of the present invention.
Preferably, the filtering energy storage unit of the frequency converter comprises a first electrolytic capacitor, a second electrolytic capacitor, a first resistor and a second resistor; one end of the first electrolytic capacitor and one end of the first resistor are both connected with the positive output end of the rectifying unit of the frequency converter, the other end of the first electrolytic capacitor is connected with one end of the second electrolytic capacitor, the other end of the first resistor is connected with one end of the second resistor, and the other ends of the second electrolytic capacitor and the second resistor are both connected with the negative output end of the rectifying unit of the frequency converter; one end of the first electrolytic capacitor connected with the second electrolytic capacitor is connected with one end of the first resistor connected with the second resistor.
Preferably, the capacitance values of the first electrolytic capacitor and the second electrolytic capacitor are the same, and the resistance values of the first resistor and the second resistor connected in series are the same.
Preferably, the first electrolytic capacitor and the second electrolytic capacitor are 1000uF to 1500uF, and the resistance values of the first resistor and the second resistor are 51k to 110k omega.
The utility model discloses for prior art have following advantage and effect:
(1) the utility model discloses a soft start circuit of a frequency converter, which comprises a microcontroller, a starting resistor and a relay; one end of a starting resistor is connected to one end of a filtering energy storage unit, which is connected with a first electrolytic capacitor and a second electrolytic capacitor, and the other end of the starting resistor is connected to a zero line connected with the input of the frequency converter; the input loop of the relay is connected with the microcontroller, and the working state of the relay is controlled by the microcontroller; the output loop of the relay is connected with the starting resistor in parallel. The utility model discloses in, soft start circuit's starting resistance and relay setting are between arbitrary one looks live wire and zero line for soft start circuit adopts arbitrary one looks live wire-zero line two-way to the mode of charging, realize the mode of soft start through this kind of charging, can greatly reduced the power and the resistance of starting resistance and the power of relay that use, consequently can use less starting resistance and relay of volume, device use cost and device occupation space have effectively been reduced, be fit for using in all kinds of rectification application circuits that take the zero line. The starting resistor is directly arranged between the output end and the input end of the frequency converter rectifying unit in the prior art, and the resistor and the relay which are high in power and large in size are avoided.
(2) In the soft start circuit of the frequency converter, one end of the filter energy storage unit, which is connected with the first electrolytic capacitor and the second electrolytic capacitor, is connected to the zero line through the starting resistor, when the frequency converter is just powered on, after the positive half period of the input power supply input alternating current, the positive half period current of the input power supply passes through the rectifying unit, the current output by the output positive end of the rectifying unit is input to the zero line through the first electrolytic capacitor and the starting resistor, thereby forming a loop, the first electrolytic capacitor is charged, at the moment, the voltage of the first electrolytic capacitor is gradually increased, the charging to the positive half period of the sine voltage is completed, after the negative half period current of the input power supply input alternating current is connected to the starting resistor through the zero line, the negative half period current of the input power supply returns to the input power supply after passing through the second electrolytic capacitor, thereby forming a loop, and the second electrolytic capacitor is used, second electrolytic capacitor voltage risees gradually this moment, accomplishes and charges well sinusoidal voltage negative half cycle, and along with the positive and negative half cycle of follow-up several cycles charges, can improve busbar voltage to normal rectification back voltage fast, consequently based on the utility model discloses a soft start circuit can both charge to energy storage filter unit at input alternating current positive and negative half cycle, has that the charge rate is fast, charge efficiency is high advantage, and based on this, the realization soft start that the converter can be quick.
(3) The utility model discloses among the soft start circuit of converter, be provided with the diode on the circuit that the positive end of rectifier unit output is connected with the first electrolytic capacitor of filtering energy storage unit, can prevent effectively through this diode that first electrolytic capacitor and second electrolytic capacitor from being reverse charged, improved the reliability and the life of converter greatly.
Drawings
Fig. 1 is a schematic circuit diagram of the soft start circuit of the present invention.
Fig. 2 is a simulation waveform diagram in embodiment 2 of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the following examples and drawings, but the present invention is not limited thereto.
Example 1
The embodiment discloses a soft start circuit of a frequency converter, which is arranged in the frequency converter, and the specific structure is as shown in fig. 1, wherein the frequency converter comprises a rectifying unit DB1 and a filtering energy storage unit connected to an output end of the rectifying unit, the rectifying unit DB1 may be a three-phase full-wave rectifying bridge as shown in fig. 1, and an output positive terminal P1 end and an output negative terminal N1 end of the full-wave rectifying bridge are respectively connected to an input end of the filtering energy storage unit.
The filtering energy storage unit of the frequency converter comprises a first electrolytic capacitor C1, a second electrolytic capacitor C2, a first resistor R1 and a second resistor R2; one ends of a first electrolytic capacitor C1 and a first resistor R1 are connected with the positive output end of the rectifying unit of the frequency converter, the other end of the first electrolytic capacitor C1 is connected with one end of a second electrolytic capacitor C2, the other end of the first resistor R1 is connected with one end of a second resistor R2, and the other ends of the second electrolytic capacitor C1 and the second resistor R2 are connected with the negative output end of the rectifying unit of the frequency converter; one end of the first electrolytic capacitor C1 connected with the second electrolytic capacitor C2 is connected with one end of the first resistor R1 connected with the second resistor R2. The first electrolytic capacitor C1 and the second electrolytic capacitor C2 are energy storage capacitors, the bus voltage is kept constant, the first resistor R1 and the second resistor R2 are voltage-sharing resistors, the voltages of the electrolytic capacitors C1 and C2 are kept equal, and the service life of the electrolytic capacitors is prolonged.
In this embodiment, the soft start circuit includes a microcontroller, a start resistor R3, and a relay K1. As shown in fig. 1, one end of the starting resistor R3 is connected to one end of the filtering energy storage unit, to which the first electrolytic capacitor C1 and the second electrolytic capacitor C2 are connected, and the other end of the starting resistor R3 is connected to the zero line N to which the input of the frequency converter is connected.
The input loop of the relay is connected with the microcontroller, and the working state of the relay is controlled by the microcontroller; the output loop of the relay is connected with the starting resistor in parallel. Specifically, in the relay input loop, one input end is connected to an IO port of the microcontroller through a resistor, and the other input end is grounded; or in the relay input loop, one input end is connected to an IO port of the microcontroller, and the other input end is grounded through a resistor. In the relay output circuit, one end of the starting resistor is connected with a movable contact of the relay, and the other end of the starting resistor is connected with a normally open static contact or a normally closed static contact of the relay.
In this embodiment, whether the relay coil is energized is controlled by a level signal output from the IO port of the microcontroller, so as to control whether the movable contact and the fixed contact in the input circuit are connected. When one end of the starting resistor is connected with the movable contact of the relay, and the other end of the starting resistor is connected with a normally open fixed contact of the relay, the movable contact and the normally open fixed contact are disconnected under the condition that the relay coil is not electrified, the starting resistor R3 is not short-circuited at the moment, the movable contact and the normally open fixed contact are attracted under the condition that the relay coil is electrified, and the starting resistor R3 is short-circuited at the moment. When one end of the starting resistor is connected with the movable contact of the relay and the other end of the starting resistor is connected with one normally closed fixed contact of the relay, the movable contact and the normally closed fixed contact are attracted under the condition that the relay coil is not electrified, the starting resistor R3 is short-circuited at the moment, the movable contact and the normally closed fixed contact are disconnected under the condition that the relay coil is not electrified, and the starting resistor R3 is not short-circuited at the moment.
In this embodiment, as shown in fig. 1, the soft start circuit further includes a diode D1, and the diode D1 is disposed on a line connecting the positive output terminal of the rectifying unit and the first electrolytic capacitor of the filtering energy storage unit, specifically: the anode of the diode D1 is connected with the positive output end of the rectifying unit, and the cathode of the diode D1 is connected with the first electrolytic capacitor C1 in the filtering energy storage unit. The diode D1 is provided in this embodiment, so that the first electrolytic capacitor C1 and the second electrolytic capacitor C2 can be effectively prevented from being reversely charged.
In this embodiment, the starting resistor may be used in a size of 100 Ω to 200 Ω/15W.
In this embodiment, the microcontroller may be a single chip microcomputer.
In this embodiment, the principle of the soft start circuit to realize soft start is as follows:
when the frequency converter is just powered on, the output loop of the control relay K1 is disconnected, namely the starting resistor R3 is not short-circuited.
In the positive half cycle of the input alternating current of the input power supply, after the current of the positive half cycle of the input power supply passes through D11, D12 or D13 of the rectifying unit DB1, the current of the positive half cycle of the input power supply is output from the output positive end of the rectifying unit DB1 and then is input into the zero line N sequentially through the first electrolytic capacitor C1 and the starting resistor R3, so that a charging loop is formed to charge the first electrolytic capacitor, the voltage of the first electrolytic capacitor C1 is gradually increased at the moment, and the charging of the positive half cycle of the sine voltage is completed;
in the negative half cycle of the alternating current input by the input power supply, the current of the negative half cycle of the input power supply flows in from the zero line, reaches the second electrolytic capacitor C2 after passing through a starting resistor connected on the zero line, then returns to the corresponding live wire of the input power supply after passing through the diodes D21, D22 or D22 in the rectifying unit DB1, so that a charging loop of the second electrolytic capacitor C2 is formed to charge the second electrolytic capacitor, and the voltage of the second electrolytic capacitor gradually rises at the moment to finish charging the positive half cycle of the sine voltage;
with the positive and negative half-cycle charging of the following periods, the bus voltage can be quickly increased to the voltage after normal rectification, thereby realizing soft start. After the soft start is finished, the relay output loop is controlled to be communicated, so that the starting resistor R3 is short-circuited, namely after the soft start is finished, the relay K1 is used for cutting off the starting resistor R3, the loss caused by the starting resistor R3 in the running process of the frequency converter is reduced, and the use efficiency of the frequency converter is improved.
Example 2
The embodiment discloses a frequency converter, which comprises a rectifying circuit DB1, a filtering energy storage unit, an inverter unit and a driving unit which are sequentially connected, and a soft start circuit which is connected between the filtering energy storage unit and a zero line and is shown in the embodiment 1, wherein the specific structure is shown in fig. 1.
In the present embodiment, the rectifying unit DB1 in the inverter uses a three-phase full-wave rectifying bridge including diodes D11, D12, D13, D21, D22, and D13 for converting the inverter input ac power into dc power. The filtering energy storage unit of the frequency converter comprises a first electrolytic capacitor C1, a second electrolytic capacitor C2, a first resistor R1 and a second resistor R2, the specific connection relation is as shown in embodiment 1, the C1 and the C2 in the filtering energy storage unit are used as energy storage capacitors, the voltage of a bus can be kept constant, the first resistor R1 and the second resistor R2 are voltage-sharing resistors, the voltages of the electrolytic capacitors C1 and C2 are kept equal, and the service life of the electrolytic capacitors is prolonged. In this embodiment, as shown in embodiment 1, the soft start circuit is disposed between the first electrolytic capacitor C1 and the zero line of the input power source, so as to prevent the inverter from being powered up to cause overcurrent breakdown damage to the rectifier unit DB1 and the subsequent IPM module (intelligent power module).
In the filtering energy storage unit of the frequency converter, the first electrolytic capacitor C1 and the second electrolytic capacitor C2 are 1000 uF-1500 uF, the first electrolytic capacitor C1 and the second electrolytic capacitor C2 can generally take 1000uF for a single-phase frequency converter, the first electrolytic capacitor C1 and the second electrolytic capacitor C2 can generally take 1500uF for a three-phase frequency converter, and the resistance values of the first resistor R1 and the second resistor R2 are 51 k-110 k omega.
In this embodiment, assuming that the power of the load connected to the frequency converter is 12kW, the load resistance is calculated to be about 25.5 Ω, when the starting resistor R3 is selected to be 100 Ω, the first electrolytic capacitor C1 and the second electrolytic capacitor C2 in the filtering energy storage unit are selected to be 1000uF, and the resistances of the first resistor R1 and the second resistor R2 are 51K Ω, during the soft start process, the power Pout, the voltage V _ out, the current I _ out on the load of the frequency converter, and the waveforms of the power Pr1, the voltage Vr1, and the current Ir1 on the starting resistor R3 are respectively as shown in fig. 2. According to the waveform in fig. 2, even if the load average power of the frequency converter reaches 11.875kW, the voltage and the current on the load and the starting resistor R3 are still switched smoothly, no overvoltage and overcurrent occur, and the average power of the starting resistor R3 in charge of soft start is approximately within 19.225W, so that the effectiveness and the reliability of the soft start circuit in the frequency converter can be effectively verified.
The soft start circuit in the frequency converter in the embodiment is not only suitable for the three-phase 380V frequency converter as shown in fig. 1, but also suitable for the frequency conversion of three phases 220V and single phase 220V.
The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be equivalent replacement modes, and all are included in the scope of the present invention.
Claims (10)
1. A soft start circuit of a frequency converter comprises a rectifying unit and a filtering energy storage unit connected to the output end of the rectifying unit, and is characterized in that the soft start circuit comprises a microcontroller, a start resistor and a relay;
one end of the starting resistor is connected to one end of the filtering energy storage unit, which is connected with the first electrolytic capacitor and the second electrolytic capacitor, and the other end of the starting resistor is connected to a zero line connected with the input of the frequency converter;
the input loop of the relay is connected with the microcontroller, and the working state of the relay is controlled by the microcontroller;
the output loop of the relay is connected with the starting resistor in parallel.
2. The soft-start circuit of a frequency converter according to claim 1, further comprising a diode; the diode sets up on the circuit that rectifier unit output positive terminal and filtering energy storage unit first electrolytic capacitor are connected, specifically does: the anode of the diode is connected with the output positive end of the rectifying unit, and the cathode of the diode is connected with the first electrolytic capacitor in the filtering energy storage unit.
3. The soft start circuit of the frequency converter according to claim 1, wherein one end of the input in the relay input loop is connected to an IO port of the microcontroller through a resistor, and the other end of the input is grounded; or in the relay input loop, one input end is connected to an IO port of the microcontroller, and the other input end is grounded through a resistor.
4. The soft start circuit of the frequency converter according to claim 1, wherein one end of the starting resistor is connected to the moving contact of the relay, and the other end of the starting resistor is connected to a normally open stationary contact or a normally closed stationary contact of the relay.
5. The soft-start circuit of a frequency converter according to claim 1, wherein the starting resistor has a size of 100 Ω -200 Ω.
6. The soft-start circuit of a frequency converter according to claim 1, wherein the microcontroller is a single-chip microcomputer.
7. A frequency converter, characterized in that it comprises a soft start circuit according to any one of claims 1 to 6.
8. The frequency converter according to claim 7, wherein the filtering energy storage unit of the frequency converter comprises a first electrolytic capacitor, a second electrolytic capacitor, a first resistor and a second resistor; one end of the first electrolytic capacitor and one end of the first resistor are both connected with the positive output end of the rectifying unit of the frequency converter, the other end of the first electrolytic capacitor is connected with one end of the second electrolytic capacitor, the other end of the first resistor is connected with one end of the second resistor, and the other ends of the second electrolytic capacitor and the second resistor are both connected with the negative output end of the rectifying unit of the frequency converter; one end of the first electrolytic capacitor connected with the second electrolytic capacitor is connected with one end of the first resistor connected with the second resistor.
9. The frequency converter according to claim 8, wherein the capacitance values of the first electrolytic capacitor and the second electrolytic capacitor are the same, and the resistance values of the first resistor and the second resistor connected in series are the same.
10. The frequency converter according to claim 8, wherein the first electrolytic capacitor and the second electrolytic capacitor are 1000uF to 1500uF, and the first resistor and the second resistor have a resistance of 51k to 110k Ω.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022806211.8U CN213661451U (en) | 2020-11-26 | 2020-11-26 | Soft start circuit of frequency converter and frequency converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022806211.8U CN213661451U (en) | 2020-11-26 | 2020-11-26 | Soft start circuit of frequency converter and frequency converter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN213661451U true CN213661451U (en) | 2021-07-09 |
Family
ID=76688190
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202022806211.8U Active CN213661451U (en) | 2020-11-26 | 2020-11-26 | Soft start circuit of frequency converter and frequency converter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN213661451U (en) |
-
2020
- 2020-11-26 CN CN202022806211.8U patent/CN213661451U/en active Active
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111355287B (en) | Vehicle-mounted charger | |
| KR100541724B1 (en) | power supply apparatus for motor and controlling method thereof | |
| CN102201666B (en) | Control circuit and use the electric machine of this control circuit | |
| CN101521472B (en) | Precharge control circuit for transducer | |
| CN107276388B (en) | PFC circuit and variable frequency air conditioner | |
| CN208846637U (en) | Power source charges control circuit, transducer air conditioning control circuit and transducer air conditioning | |
| KR20130119338A (en) | Rectifier circuit and motor driving device using the same | |
| CN201388162Y (en) | Pre-charge control circuit of transducer | |
| CN212579628U (en) | Energy conversion device and vehicle | |
| CN109617445B (en) | DC side charging soft start circuit and method for five-level converter | |
| CN104868708A (en) | Power-on buffering and bus discharge circuit for frequency converter | |
| CN213661451U (en) | Soft start circuit of frequency converter and frequency converter | |
| CN218243366U (en) | Single-phase standby reactive power consumption control circuit in switching power supply | |
| CN202652055U (en) | Electrolytic capacitor charging circuit | |
| CN209627227U (en) | Drive control circuit, air-conditioner controller and air conditioner | |
| CN106787967B (en) | Universal frequency converter with counter-current resistor and control method | |
| CN209608542U (en) | Drive control circuit, air-conditioner controller and air conditioner | |
| CN202586862U (en) | Alternating current motor drive device with charging function | |
| CN204669215U (en) | A kind of frequency converter powers on and cushions and bus discharge circuit | |
| CN212380983U (en) | Charging circuit of air conditioner variable frequency controller without impulse current | |
| CN218041202U (en) | Controllable filter circuit and power converter | |
| CN110422066A (en) | A kind of vehicle-mounted charging device | |
| CN218829605U (en) | Soft start circuit of UPS relay | |
| CN221669764U (en) | Motor driving circuit | |
| CN220087158U (en) | Four-quadrant frequency converter and electronic equipment |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |