CN103246298A - Control circuit for constant temperature and constant temperature device - Google Patents

Abstract

The utility model provides a control circuit for constant temperature, constant temperature equipment, includes control circuit board, control circuit board is equipped with one-level refrigeration motor output control interface, second grade refrigeration motor output control interface, heating device output control interface, humidification device output control interface, still includes the one-level refrigeration motor, second grade refrigeration motor, heating device, the humidification device that are connected with three phase current through solid state relay respectively, one-level refrigeration motor, second grade refrigeration motor, heating device, humidification device's solid state relay respectively with last corresponding output interface of control circuit is connected. The solid-state relay has no mechanical parts, the solid device completes the contact function, the solid-state relay can work in the environment of high impact and vibration because of no moving parts, and the inherent characteristics of the components forming the solid-state relay determine that the solid-state relay has long service life and high reliability.

Description

A control circuit for constant temperature and constant temperature device

technical field

The invention relates to a control circuit, in particular to a constant temperature, a control circuit of a constant temperature device .

Background technique

In the prior art, there are some constant temperature and mechanisms in constant temperature devices that will be turned on or off according to the needs of the working environment. Usually, an AC contactor is used for breaking control, which has the following disadvantages: the control coil consumes a lot of energy, The balance effect cannot be achieved, it is easy to be broken down, and the noise is loud when working.

Contents of the invention

The object of the present invention is to provide a control circuit for a constant temperature and constant temperature device, which can work in a high impact and vibration environment.

A control circuit for constant temperature and constant temperature devices is provided, including a control circuit board, and the control circuit board is provided with a primary refrigeration motor output control interface, a secondary refrigeration motor output control interface, a heating device output control interface, and a heating device output control interface. Interface, humidification device output control interface, also includes a primary refrigeration motor, secondary refrigeration motor, heating device, humidification device connected to the three-phase power supply through solid state relays, the primary refrigeration motor, secondary refrigeration motor, heating The solid state relays of the device and the humidifying device are respectively connected to corresponding output interfaces on the control circuit.

The above-mentioned control circuit for constant temperature and constant temperature devices also includes a phase-deficit and reverse-phase control module connected to the three-phase power supply.

Advantages of the present invention: high life and high reliability: solid state relays have no mechanical parts, and the contact function is completed by solid devices. Since there are no moving parts, they can work in high impact and vibration environments. The inherent characteristics of the device determine the long life and high reliability of the solid state relay. High sensitivity, low control power, and good electromagnetic compatibility: the solid state relay has a wide input voltage range and low drive power, and is compatible with most logic integrated circuits without buffers or drivers. Fast switching: Solid state relays can switch from a few milliseconds to a few microseconds due to the use of solid-state devices. Low electromagnetic interference: Solid state relays have no input "coils", no trigger arcing and bounce, thus reducing electromagnetic interference. Most of the AC output solid state relays are a zero-voltage switch, which is turned on at zero voltage and turned off at zero current, which reduces the sudden interruption of the current waveform, thereby reducing the switching transient effect; energy-saving balance; heating can be output in proportion.

Description of drawings

Fig. 1 is the schematic diagram of the circuit of the present invention.

Detailed ways

With reference to shown in Fig. 1, design a kind of control circuit that is used for constant temperature, constant temperature device, be provided with control circuit board, control circuit board is provided with primary refrigeration motor output control interface 41, secondary refrigeration motor output control interface 31, heating device output The control interface 21, the output control interface 11 of the humidifying device, also includes the first-stage refrigeration motor 9, the second-stage refrigeration motor 8, the heating device 7, and the humidification unit respectively connected to the three-phase power supply through four solid state relays 1, 2, 3, and 4. The four solid-state relays 1, 2, 3, and 4 of the device 6, the primary refrigeration motor 9, the secondary refrigeration motor 8, the heating device 7, and the humidifying device 6 are respectively connected to the corresponding output interfaces 11, 21, and 31 on the control circuit. , 41 are connected.

In the above-mentioned control circuit for constant temperature and constant temperature devices, there is also a phase loss and reverse phase control module 5 connected to the three-phase power supply, which can disconnect the circuit when there is a phase loss or phase error, so that the protection device will not be damaged.

Since the present invention uses a semiconductor device as a non-contact switch device with relay characteristics as a switching device, the single-phase SSR is a four-terminal active device, wherein two input control terminals, two output terminals, and optical isolation between the input and output. After adding a DC or pulse signal to a certain current value, the output terminal can change from off state to on state. AC solid state relays are divided into voltage zero-crossing conduction type (referred to as zero-crossing type) and random conduction type (referred to as random type) according to the switching mode. According to the output switching element, there are bidirectional thyristor output type (common type) and one-way adjustable The SCR anti-parallel type (enhanced type) is divided into pin-plug type for printed circuit board (natural cooling, without radiator) and device type fixed on the metal base plate (cooled by radiator) according to the installation method. There are also wide range input (DC3~32V) constant current source type and series resistance current limiting type, etc. SSR solid state relays can be divided into zero voltage type (Z) and phase modulation type (P) in the form of triggering. When a suitable control signal IN is applied to the input, the P-type SSR turns on immediately. When IN is removed and the load current is lower than the bidirectional thyristor maintenance current (AC commutation), the SSR is turned off. The Z-type SSR includes a zero-crossing detection circuit inside. When the input signal IN is applied, the SSR can only be turned on when the load power supply voltage reaches the zero-crossing area, and it may cause a maximum delay of half a cycle of the power supply. Z-type SSR has the same shutdown conditions as P-type, but because the load operating current is similar to a sine wave and the high-order harmonic interference is small, it is widely used. When an inductive load is added, before the input signal cuts off t1, the bidirectional thyristor is turned on, and the current lags the power supply voltage by 90O (when purely inductive). At t1, the input control signal is withdrawn, and the bidirectional thyristor is turned off when it is less than the holding current (t2), and the thyristor will withstand the reverse voltage with a high voltage rise rate dv/dt. This voltage will be positively fed back to the gate through the junction capacitance inside the triac. If it exceeds the bidirectional thyristor commutation dv/dt index (typical value 10V/ s, it will cause long commutation recovery time or even failure. Since the one-way thyristor (enhanced SSR) is in the unipolar working state, at this time Only limited by the static voltage rise rate (typical value 200V/ s), the enhanced solid state relay HS series has a commutation dv/dt index that is 5 to 20 times higher than that of ordinary SSRs. Due to the use of two high-power unidirectional Silicon-controlled anti-parallel connection changes the current distribution and heat conduction conditions, and improves the SSR output power. In high-power applications, whether it is an inductive load or a resistive load, the withstand voltage, current shock resistance and product reliability are all excellent. More than ordinary solid state relays.

Claims (2)

1. A control circuit for constant temperature and constant temperature devices, including a control circuit board, the control circuit board is provided with a primary refrigeration motor output control interface, a secondary refrigeration motor output control interface, a heating device output control interface, and a humidification device output The control interface is characterized in that: it also includes a primary refrigeration motor, a secondary refrigeration motor, a heating device, and a humidifying device connected to the three-phase power supply through a solid state relay, and the primary refrigeration motor, secondary refrigeration motor, and heating device 1. The solid state relays of the humidifying device are respectively connected to the corresponding output interfaces on the control circuit. 2 . The control circuit for constant temperature and constant temperature devices according to claim 1 , further comprising a phase-deficiency and reverse-phase control module connected to the three-phase power supply. 3 .

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