CN217883260U

CN217883260U - Control circuit for improving conversion rate of variable frequency controller

Info

Publication number: CN217883260U
Application number: CN202221204668.4U
Authority: CN
Inventors: 朱宇杉; 陈宇; 胡扶遥; 刘龙球; 刘猛
Original assignee: Huangshi Donper Compressor Co Ltd
Current assignee: Huangshi Donper Compressor Co Ltd
Priority date: 2022-05-18
Filing date: 2022-05-18
Publication date: 2022-11-22
Anticipated expiration: 2032-05-18

Abstract

The utility model relates to a promote control circuit of frequency conversion controller conversion rate, including EMC filtering and rectifier module, surge current control circuit module, inverter circuit module, motor, MCU power input, MCU the control unit module. Aiming at the problems that in the prior art, a plurality of components are needed to be cooperatively controlled, a control chain is complex, the cost of the components is high, the operation and conversion efficiency of a frequency converter is low, and the stability of a circuit structure is reduced, the utility model realizes the suppression of surge current through the R1 surge current suppression resistor of a surge current control circuit; after the electrolytic capacitor is fully charged, the MCU controls the conduction of the electrolytic capacitor through the grid of the control switch M1, the R1 surge current is short-circuited, components and parts are reduced while the reliability of a circuit system is ensured, the cost is saved, and the technical effect of improving the conversion efficiency of the frequency converter in the operation process is also effectively achieved.

Description

Control circuit for improving conversion rate of variable frequency controller

Technical Field

The utility model relates to a frequency conversion compressor technical field especially relates to a promote control circuit of frequency conversion controller conversion rate.

Background

In the electronic equipment in daily life, no matter small-power electronic equipment such as a bulb and the like or high-power electronic equipment such as a frequency converter and the like in household appliances, once the equipment is powered on, because the running current of the equipment needs to reach 2-3 times of rated working current in a short time, surge pulse current can be formed in an equipment loop in the process, if the pulse current is not inhibited, the pulse current can cause great impact on a relay switch and a load of a terminal user, and the service life of the electronic equipment can be shortened under certain extreme conditions. At present, two novel circuit design schemes are available to achieve the purpose of suppressing surge current, one is a circuit structure for increasing bolt lock control, see fig. 2; one is a capacitor pre-charging circuit structure, see fig. 3; both of these schemes are hardware implementations.

In the circuit structure with the added bolt-lock control, as shown in fig. 2, two mosfets need to be configured and used, which are a P-type Mosfet and an N-type Mosfet, respectively, and meanwhile, a PNP-type triode and a Z3 voltage regulator tube are also needed to realize the bolt-lock function on the mosfets together, so that the mosfets are conducted and the NTC resistor is short-circuited. In the circuit structure, a plurality of components are required to be cooperatively controlled, a control chain is complex, the cost of the components is high, and the operation and conversion efficiency of the frequency converter is low.

In the capacitor pre-charging circuit structure, as shown in fig. 3, the electrolytic capacitors E2 and E3 need to be charged first, then the capacitor E1 needs to be charged, and after the capacitor E1 is charged, the Q1 Mosfet can be turned on and the NTC resistor is short-circuited. In the circuit structure, the Mosfet is switched on or off only through the charging and discharging process of the charging capacitor, the conversion rate of the frequency converter cannot be timely improved, and the stability of the circuit structure is also reduced.

In a word, above-mentioned two kinds of circuit structure all are pure hardware scheme, and too loaded down with trivial details complicacy, owing to select for use too much components and parts to reduce converter plate dynamic efficiency and conversion rate among the circuit structure, too single simple and easy can not in time promote converter plate efficiency, and the reliability deviation. Therefore, components are reduced, and the cost is reduced; promote converter operating efficiency and conversion efficiency is the problem of serving the solution.

Disclosure of Invention

To the above-mentioned technical problem among the correlation technique, the utility model provides a refrigerator frequency conversion controller of low stand-by power consumption can overcome above-mentioned prior art not enough. The technical scheme is as follows:

a control circuit for improving the conversion rate of a variable frequency controller comprises an EMC filtering and rectifying module, a surge current control circuit module, an inverter circuit module, a motor, an MCU power input and an MCU control unit module; the EMC filtering and rectifying module comprises a filtering capacitor CX1, a common-mode inductor LC1, a filtering capacitor CX2, a filtering capacitor CY1, a filtering capacitor CY2, a passive PFC inductor L1, a rectifier bridge DB1 and a filtering capacitor C1; the surge current control circuit module comprises a bus electrolytic capacitor Cbus, a Mosfet M1, a control switch M1 and a surge current suppression resistor R1; the inverter circuit module comprises 6 IGBT type or Mosfet type power switch components; one end of a filter capacitor CX1 of the EMC filtering and rectifying module is connected with one end of a primary side of a common-mode inductor LC1, the other end of the primary side of the common-mode inductor LC1 is respectively connected with one end of a filter capacitor CX2, one end of a filter capacitor CY1 and one end of a passive PFC inductor L1; the other end of the passive PFC inductor L1 is connected with a No. 2 pin of the rectifier bridge DB 1; the 3 rd pin of the rectifier bridge DB1 is respectively connected with the other end of the filter capacitor CY2, the other end of the filter capacitor CX2 and the 4 th end of the common-mode inductor LC 1; the other end of the filter capacitor CY1 and one end of the filter capacitor CY2 are grounded. The 2 nd end of the common mode inductor LC1 is connected with the other end of the filter capacitor CX 1; the 1 st pin output by the rectifier bridge DB1 is respectively connected with one end of a filter capacitor C1, the positive end of a bus electrolytic capacitor Cbus of the surge current control circuit module and the drain (D) ends of power switches SW1, SW2 and SW3 in the inverter circuit module; SW1, SW2, SW3, SW4, SW5 and SW6 of the power switch are connected with the surge current suppression resistor R1 in parallel; the other end of the bus electrolytic capacitor Cbus is connected with a drain electrode of the Mosfet M1; the other end of the current detection resistor R1 of the surge current control circuit module is respectively connected with one end of SW4, SW5 and SW6 of the power switch in the inverter circuit module, the source electrode of the Mosfet M1, the other end of the filter capacitor C1 and the 4 th pin of the rectifier bridge DB 1.

Furthermore, the sources of the SW1 and SW4 of the power switch are connected with the 1 st pin of the motor, the sources of the SW2 and SW5 of the power switch are connected with the 2 nd pin of the motor, and the sources of the SW3 and SW6 of the power switch are connected with the 3 rd pin of the motor.

Further, the MCU power input module is connected with the MCU control unit module.

Further, the MCU is respectively connected with the grid of the control switch M1 and the grids of 6 power switches SW1 to SW6 in the inverter circuit.

The utility model discloses beneficial effect: the patent relates to a control circuit for improving the conversion rate of a variable frequency controller, wherein in the process of the initial electrification of a frequency converter, the suppression of surge current is realized through an R1 surge current suppression resistor of a surge current control circuit; after the electrolytic capacitor at the bus end is fully charged, the MCU controls the conduction of the electrolytic capacitor through the grid of the control switch M1, so that the R1 surge current suppression resistor is short-circuited, the technical effect of effectively improving the conversion efficiency of the frequency converter in the operation process while ensuring the reliability of a circuit system is achieved, components are reduced, and the cost is saved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a structural diagram of a control circuit for increasing conversion rate of a variable frequency controller.

Fig. 2 is a circuit diagram of a prior art with added latch control.

Fig. 3 is a block diagram of a prior art capacitor precharge circuit.

FIG. 4 is a graph showing the effect of the experimental result data curve.

Detailed Description

The technical solution of the present invention will be clearly and completely described below with reference to fig. 1 and 4 of the drawings attached to the specification of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, not all embodiments; all other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention belong to the scope of the present invention.

Embodiment 1 discloses a control circuit for improving conversion rate of a variable frequency controller, which comprises an EMC filtering and rectifying module, a surge current control circuit module, an inverter circuit module, a motor, an MCU power input and an MCU control unit module; EMC filtering and rectifier module include filter capacitance CX1, common mode inductance LC1, filter capacitance CX2, filter capacitance CY1, filter capacitance CY2, passive PFC inductance L1, rectifier bridge DB1 and filter capacitance C1. The circuit structure of EMC filtering and rectifier module can avoid the high frequency electromagnetic noise in the circuit to return the electric wire netting, passive PFC inductance is used for improving the harmonic current that frequency conversion board power factor and limit value frequency conversion board produced, the rectifier bridge is used for passing through full-bridge full wave rectification conversion generating line direct current output with the alternating current of electric wire netting input. The surge current control circuit module comprises a bus electrolytic capacitor Cbus, a Mosfet M1, a control switch M1 and a surge current suppression resistor R1; the Cbus electrolytic capacitor is used for filtering bus direct current output by the rectifier bridge, and the surge current suppression resistor R1 is used for suppressing surge current in a circuit structure when the circuit is powered on for the first time. In the time interval when the alternating current enters the frequency conversion board for the first time, the control switch M1 keeps the disconnection state, and the current flows through the surge current suppression resistor. And in the time interval before the compressor is started, the control switch M1 is kept in the off state continuously, and the surge current is restrained continuously. After the bus electrolytic capacitor is fully charged/discharged, the control switch M1 is switched to be in a conducting state in a time interval after surge current in the circuit is remarkably reduced, and the conversion efficiency of the frequency converter in the operation process is effectively improved by short-circuiting R1 surge current suppression resistance through the self characteristics of components; one end of a filter capacitor CX1 of the EMC filtering and rectifying module is connected with one end of a primary side of a common-mode inductor LC1, the other end of the primary side of the common-mode inductor LC1 is respectively connected with one end of a filter capacitor CX2, one end of a filter capacitor CY1 and one end of a passive PFC inductor L1; the other end of the passive PFC inductor L1 is connected with a No. 2 pin of the rectifier bridge DB 1; the 3 rd pin of the rectifier bridge DB1 is respectively connected with the other end of the filter capacitor CY2, the other end of the filter capacitor CX2 and the 4 th end of the common-mode inductor LC 1; the other end of the filter capacitor CY1 and one end of the filter capacitor CY2 are grounded. The 2 nd end of the common mode inductor LC1 is connected with the other end of the filter capacitor CX 1; and the 1 st pin output by the rectifier bridge DB1 is respectively connected with one end of a filter capacitor C1, the positive end of a bus electrolytic capacitor Cbus of the surge current control circuit module and the drain ends of power switches SW1, SW2 and SW3 in the inverter circuit module. The inverter circuit module comprises 6 IGBT type or Mosfet type power switch components, and current is filtered by the bus electrolytic capacitor and then flows to the inverter circuit module. SW1, SW2, SW3, SW4, SW5 and SW6 of the power switch are connected with the surge current suppression resistor R1 in parallel; the other end of the bus electrolytic capacitor Cbus is connected with a drain electrode of the Mosfet M1; the other end of a current detection resistor R1 of the surge current control circuit module is respectively connected with one ends of SW4, SW5 and SW6 of a power switch in the inverter circuit module, a source electrode of the Mosfet M1, the other end of the filter capacitor C1 and a pin 4 of the rectifier bridge DB 1; the source electrodes of the SW1 and the SW4 of the power switch are connected with the 1 st pin of the motor, the source electrodes of the SW2 and the SW5 of the power switch are connected with the 2 nd pin of the motor, and the source electrodes of the SW3 and the SW6 of the power switch are connected with the 3 rd pin of the motor; the MCU is respectively connected with the grid of the control switch M1 and the grids of 6 power switches SW1 to SW6 in the inverter circuit; and the MCU power input module is connected with the MCU control unit module. The current detection resistor is used for measuring and acquiring motor feedback phase current information by the MCU, the divider resistor from bus voltage to the MCU is used for measuring and acquiring bus voltage information by the MCU, voltage waveforms among three phases of the motor are estimated by combining a motor back electromotive force model, the MCU control unit estimates continuous rotor positions, and FOC magnetic field directional control defined by mathematical logic is realized.

Example 2, based on the test results of the present application, the technical effect is illustrated step by step, see fig. 4.

STEP1, when the alternating current does not flow into the frequency converter, a control switch M1 connected with an R1 surge current suppression resistor in parallel is in an off state; in the time interval when the alternating current enters the frequency conversion board for the first time, the control switch M1 keeps the disconnection state, and the current flows through the surge current suppression resistor.

STEP2, when the alternating current flows into the frequency converter, the control switch M1 connected with the R1 surge current suppression resistor in parallel is in an off state, the input current only flows through the R1 surge current suppression resistor, and the circuit structure can effectively suppress the surge current.

STEP3, the MCU controls a control switch M1 connected with the R1 surge current suppression resistor in parallel to be conducted, so that the electric power consumption on the R1 surge current suppression resistor is effectively reduced; after the bus electrolytic capacitor is fully charged/discharged, the control switch M1 is switched to be in a conducting state in a time interval after surge current in the circuit is remarkably reduced, and the conversion efficiency of the frequency converter in the operation process is effectively improved by short-circuiting R1 surge current suppression resistance through the self characteristics of components.

STEP 4. During the running period of the frequency converter, the control switch M1 connected with the R1 surge current suppression resistor in parallel keeps a conducting state continuously.

STEP5, the control switch M1 connected with the R1 surge current suppression resistor in parallel is in an off state during the period that the alternating current stops flowing into the frequency converter.

The suppression of the surge current is realized through the R1 surge current suppression resistor of the surge current control circuit; after the electrolytic capacitor is fully charged, the MCU controls the conduction of the electrolytic capacitor through the grid of the control switch M1, so that the R1 surge current is short-circuited to ensure the reliability of a circuit system.

The present invention is not limited to the above-mentioned preferred embodiments, and any person can obtain other products in various forms according to the teaching of the present invention, but any change in the method thereof, whether having the same or similar technical solution as the present application, falls within the protection scope of the present invention.

Claims

1. The utility model provides a promote control circuit of variable frequency controller conversion, includes EMC filtering and rectifier module, surge current control circuit module, inverter circuit module, motor, MCU power input, MCU the control unit module, its characterized in that: the EMC filtering and rectifying module comprises a filtering capacitor CX1, a common-mode inductor LC1, a filtering capacitor CX2, a filtering capacitor CY1, a filtering capacitor CY2, a passive PFC inductor L1, a rectifier bridge DB1 and a filtering capacitor C1; the surge current control circuit module comprises a bus electrolytic capacitor Cbus, a Mosfet M1, a control switch M1 and a surge current suppression resistor R1; the inverter circuit module comprises 6 IGBT type or Mosfet type power switch components; one end of a filter capacitor CX1 of the EMC filtering and rectifying module is connected with one end of a primary side of a common mode inductor LC1, and the other end of the primary side of the common mode inductor LC1 is respectively connected with one end of a filter capacitor CX2, one end of the filter capacitor CY1 and one end of a passive PFC inductor L1; the other end of the passive PFC inductor L1 is connected with a No. 2 pin of the rectifier bridge DB 1; a 3 rd pin of the rectifier bridge DB1 is respectively connected with the other end of the filter capacitor CY2, the other end of the filter capacitor CX2 and a 4 th end of the common mode inductor LC 1; the other end of the filter capacitor CY1 and one end of the filter capacitor CY2 are grounded; the 2 nd end of the common mode inductor LC1 is connected with the other end of the filter capacitor CX 1; the 1 st pin output by the rectifier bridge DB1 is respectively connected with one end of a filter capacitor C1, the positive end of a bus electrolytic capacitor Cbus of the surge current control circuit module and the drain (D) ends of power switches SW1, SW2 and SW3 in the inverter circuit module; SW1, SW2, SW3, SW4, SW5 and SW6 of the power switch are connected with the surge current suppression resistor R1 in parallel; the other end of the bus electrolytic capacitor Cbus is connected with a drain electrode of the Mosfet M1; the other end of the current detection resistor R1 of the surge current control circuit module is respectively connected with one end of each of SW4, SW5 and SW6 of the power switch in the inverter circuit module, the source electrode of the Mosfet M1, the other end of the filter capacitor C1 and the 4 th pin of the rectifier bridge DB 1.

2. The control circuit for increasing the conversion rate of the variable frequency controller according to claim 1, wherein: the source electrodes of the SW1 and the SW4 of the power switch are connected with the 1 st pin of the motor, the source electrodes of the SW2 and the SW5 of the power switch are connected with the 2 nd pin of the motor, and the source electrodes of the SW3 and the SW6 of the power switch are connected with the 3 rd pin of the motor.

3. The control circuit for increasing the conversion rate of the variable frequency controller according to claim 1, wherein: and the MCU power input module is connected with the MCU control unit module.

4. The control circuit for increasing the conversion rate of the variable frequency controller according to claim 1, wherein: the MCU is respectively connected with the grid of the control switch M1 and the grids of 6 power switches SW 1-SW 6 in the inverter circuit.