Motor drive and method of controlling a temperature of a motor drive
There is provided a motor drive comprising: a temperature sensor arranged to sense a temperature of the drive; a braking resistor; switching means arranged when activated to cause current to flow to the braking resistor; and controlling means arranged to activate the switching means when the sensed temperature falls below a predetermined threshold. There is also provided a method of controlling a temperature of a motor drive comprising a braking resistor. The method comprising comprises: monitoring a temperature of the drive; and activating switching means to cause current to flow to the braking resistor when the monitored temperature falls below a predetermined threshold.
1. A motor drive comprising:
a temperature sensor;
a braking resistor;
a plurality of components each having a critical temperature at which the component fails or malfunctions; the temperature sensor arranged to sense a temperature of a component of the plurality of components that is most sensitive to low temperatures
switching means arranged when activated to cause current to flow to the braking resistor; and
controlling means arranged to activate the switching means when the sensed temperature of the component that is most sensitive to low temperatures falls below a first predetermined threshold, to activate cooling means to cool the motor drive when the sensed temperature of the component that is most sensitive to low temperatures rises above a second predetermined threshold, and to deactivate said cooling means when the sensed temperature falls below the first predetermined threshold.
2. The motor drive of claim 1 , wherein the component is one of: a braking transistor, a DC bus, an inverter, a power stage, a rectifier, a control stage, and a heat sink.
3. The motor drive of claim 1 , wherein the braking resistor includes a strip heater.
4. The motor drive of claim 1 , wherein the braking resistor includes embedded in a heat sink.
5. The motor drive of claim 1 , wherein the switching means includes a braking transistor.
6. The motor drive of claim 1 , wherein the cooling means includes a fan.
7. A method of controlling a temperature of a motor drive comprising a braking resistor and a plurality of components each having a critical temperature at which the component fails or malfunctions, the method comprising:
monitoring a temperature of a component of the plurality of components being most sensitive to low temperatures;
activating switching means to cause current to flow to the braking resistor when the monitored temperature of the component that is most sensitive to low temperatures falls below a first predetermined threshold;
activating cooling means to cool the motor drive when the monitored temperature of the component that is most sensitive to low temperatures rises above a second predetermined threshold; and
deactivating said cooling means when the monitored temperature falls below the first predetermined threshold.
8. The method of claim 7 , wherein the component is one of: a braking transistor, a DC bus, an inverter, a power stage, a rectifier, a control stage, and a heat sink.
9. The method of claim 7 , wherein the braking resistor includes a strip heater.
10. The method of claim 7 , wherein the braking resistor includes embedded in a heat sink.
11. The method of claim 7 , wherein the switching means includes a braking transistor.
12. A machine-readable medium having instructions stored thereon, wherein when read by a machine the instructions are configured to execute the steps of claim 7 .
13. The method of claim 7 , wherein the cooling means includes a fan.