Gas water heater and constant-temperature control method and device thereof

Abstract

The invention discloses a constant-temperature control method of a gas water heater. The constant-temperature control method comprises the following steps that the water inlet temperature and the water inlet flow of the gas water heater are detected; the heat load required by the gas water heater to heat inlet water from the water inlet temperature to a preset temperature according to the water inlet temperature, the water inlet flow and the preset temperature; the current of a proportional valve of the gas water heater is adjusted according to the heat load and an initial adjusting rule so asto enable the water outlet temperature of the gas water heater to reach the preset temperature; when the water outlet temperature reaches the preset temperature, the current of the proportional valveand the current heat load of the gas water heater are acquired; and the initial adjusting rule is updated according to the current of the proportional valve and the current heat load so as to adjustthe current of the proportional valve according to the updated adjusting rule. According to the constant-temperature control method, the startup overshoot of the gas water heater can be reduced, start-up constant-temperature time is shortened, and therefore the constant-temperature performance of the gas water heater can be improved. The invention further provides a constant-temperature control device of the gas water heater and the gas water heater.

Description

technical field [0001] The invention relates to the technical field of gas water heaters, in particular to a constant temperature control method for a gas water heater, a constant temperature control device for a gas water heater and a gas water heater. Background technique [0002] In related technologies, most of the constant temperature control of gas water heaters adopts the PID (Proportion Integral Derivative, proportional integral derivative) algorithm, but the PID algorithm is only accurate in the control of the linear system, and the control of the nonlinear system and the hysteresis system is prone to overshoot and overshoot. Since the gas water heater is a lagging system, the constant temperature time is relatively long (generally 40-60 seconds), the outlet water temperature fluctuates greatly (generally 2-3°C), and the temperature overshoot is high (generally 2-3°C). Contents of the invention [0003] The present invention aims to solve one of the technical prob...

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Problems solved by technology

[0002] In related technologies, most of the constant temperature control of gas water heaters adopts the PID (Proportion Integral Derivative, proportional integral derivative) algorithm, but the PID algorithm is only accurate in the control of the linear system, and it is easy to produce overshoot and overshoot in the control of the nonlinear system and the hysteresis system.

Since the gas water heater is a lagging system, the constant temperature time is relatively long (generally 40-60 seconds), the outlet water temperature fluctuates greatly (generally 2-3°C), and the temperature overshoot is high (generally 2-3°C)

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